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1373 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Kefeng Wang
|
cda6d93672 |
mm: memory: make numa_migrate_prep() to take a folio
In preparation for large folio numa balancing, make numa_migrate_prep() to take a folio, no functional change intended. Link: https://lkml.kernel.org/r/20230921074417.24004-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kefeng Wang
|
6695cf68b1 |
mm: memory: use a folio in do_numa_page()
Numa balancing only try to migrate non-compound page in do_numa_page(), use a folio in it to save several compound_head calls, note we use folio_estimated_sharers(), it is enough to check the folio sharers since only normal page is handled, if large folio numa balancing is supported, a precise folio sharers check would be used, no functional change intended. Link: https://lkml.kernel.org/r/20230921074417.24004-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kefeng Wang
|
6561045345 |
mm: memory: add vm_normal_folio_pmd()
Patch series "mm: convert numa balancing functions to use a folio", v2. do_numa_pages() only handles non-compound pages, and only PMD-mapped THPs are handled in do_huge_pmd_numa_page(). But a large, PTE-mapped folio will be supported so let's convert more numa balancing functions to use/take a folio in preparation for that, no functional change intended for now. This patch (of 6): The new vm_normal_folio_pmd() wrapper is similar to vm_normal_folio(), which allow them to completely replace the struct page variables with struct folio variables. Link: https://lkml.kernel.org/r/20230921074417.24004-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20230921074417.24004-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kefeng Wang
|
73eab3ca48 |
mm: migrate: convert migrate_misplaced_page() to migrate_misplaced_folio()
At present, numa balance only support base page and PMD-mapped THP, but we will expand to support to migrate large folio/pte-mapped THP in the future, it is better to make migrate_misplaced_page() to take a folio instead of a page, and rename it to migrate_misplaced_folio(), it is a preparation, also this remove several compound_head() calls. Link: https://lkml.kernel.org/r/20230913095131.2426871-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Mateusz Guzik
|
bc0c335760 |
mm: remove remnants of SPLIT_RSS_COUNTING
The feature got retired in
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Linus Torvalds
|
df57721f9a |
Add x86 shadow stack support
Convert IBT selftest to asm to fix objtool warning -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEV76QKkVc4xCGURexaDWVMHDJkrAFAmTv1QQACgkQaDWVMHDJ krAUwhAAn6TOwHJK8BSkHeiQhON1nrlP3c5cv0AyZ2NP8RYDrZrSZvhpYBJ6wgKC Cx5CGq5nn9twYsYS3KsktLKDfR3lRdsQ7K9qtyFtYiaeaVKo+7gEKl/K+klwai8/ gninQWHk0zmSCja8Vi77q52WOMkQKapT8+vaON9EVDO8dVEi+CvhAIfPwMafuiwO Rk4X86SzoZu9FP79LcCg9XyGC/XbM2OG9eNUTSCKT40qTTKm5y4gix687NvAlaHR ko5MTsdl0Wfp6Qk0ohT74LnoA2c1g/FluvZIM33ci/2rFpkf9Hw7ip3lUXqn6CPx rKiZ+pVRc0xikVWkraMfIGMJfUd2rhelp8OyoozD7DB7UZw40Q4RW4N5tgq9Fhe9 MQs3p1v9N8xHdRKl365UcOczUxNAmv4u0nV5gY/4FMC6VjldCl2V9fmqYXyzFS4/ Ogg4FSd7c2JyGFKPs+5uXyi+RY2qOX4+nzHOoKD7SY616IYqtgKoz5usxETLwZ6s VtJOmJL0h//z0A7tBliB0zd+SQ5UQQBDC2XouQH2fNX2isJMn0UDmWJGjaHgK6Hh 8jVp6LNqf+CEQS387UxckOyj7fu438hDky1Ggaw4YqowEOhQeqLVO4++x+HITrbp AupXfbJw9h9cMN63Yc0gVxXQ9IMZ+M7UxLtZ3Cd8/PVztNy/clA= =3UUm -----END PGP SIGNATURE----- Merge tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 shadow stack support from Dave Hansen: "This is the long awaited x86 shadow stack support, part of Intel's Control-flow Enforcement Technology (CET). CET consists of two related security features: shadow stacks and indirect branch tracking. This series implements just the shadow stack part of this feature, and just for userspace. The main use case for shadow stack is providing protection against return oriented programming attacks. It works by maintaining a secondary (shadow) stack using a special memory type that has protections against modification. When executing a CALL instruction, the processor pushes the return address to both the normal stack and to the special permission shadow stack. Upon RET, the processor pops the shadow stack copy and compares it to the normal stack copy. For more information, refer to the links below for the earlier versions of this patch set" Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/ Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/ * tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits) x86/shstk: Change order of __user in type x86/ibt: Convert IBT selftest to asm x86/shstk: Don't retry vm_munmap() on -EINTR x86/kbuild: Fix Documentation/ reference x86/shstk: Move arch detail comment out of core mm x86/shstk: Add ARCH_SHSTK_STATUS x86/shstk: Add ARCH_SHSTK_UNLOCK x86: Add PTRACE interface for shadow stack selftests/x86: Add shadow stack test x86/cpufeatures: Enable CET CR4 bit for shadow stack x86/shstk: Wire in shadow stack interface x86: Expose thread features in /proc/$PID/status x86/shstk: Support WRSS for userspace x86/shstk: Introduce map_shadow_stack syscall x86/shstk: Check that signal frame is shadow stack mem x86/shstk: Check that SSP is aligned on sigreturn x86/shstk: Handle signals for shadow stack x86/shstk: Introduce routines modifying shstk x86/shstk: Handle thread shadow stack x86/shstk: Add user-mode shadow stack support ... |
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Linus Torvalds
|
b96a3e9142 |
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in add_to_avail_list")
- Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which
reduces the special-case code for handling hugetlb pages in GUP. It
also speeds up GUP handling of transparent hugepages.
- Peng Zhang provides some maple tree speedups ("Optimize the fast path
of mas_store()").
- Sergey Senozhatsky has improved te performance of zsmalloc during
compaction (zsmalloc: small compaction improvements").
- Domenico Cerasuolo has developed additional selftest code for zswap
("selftests: cgroup: add zswap test program").
- xu xin has doe some work on KSM's handling of zero pages. These
changes are mainly to enable the user to better understand the
effectiveness of KSM's treatment of zero pages ("ksm: support tracking
KSM-placed zero-pages").
- Jeff Xu has fixes the behaviour of memfd's
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED").
- David Howells has fixed an fscache optimization ("mm, netfs, fscache:
Stop read optimisation when folio removed from pagecache").
- Axel Rasmussen has given userfaultfd the ability to simulate memory
poisoning ("add UFFDIO_POISON to simulate memory poisoning with UFFD").
- Miaohe Lin has contributed some routine maintenance work on the
memory-failure code ("mm: memory-failure: remove unneeded PageHuge()
check").
- Peng Zhang has contributed some maintenance work on the maple tree
code ("Improve the validation for maple tree and some cleanup").
- Hugh Dickins has optimized the collapsing of shmem or file pages into
THPs ("mm: free retracted page table by RCU").
- Jiaqi Yan has a patch series which permits us to use the healthy
subpages within a hardware poisoned huge page for general purposes
("Improve hugetlbfs read on HWPOISON hugepages").
- Kemeng Shi has done some maintenance work on the pagetable-check code
("Remove unused parameters in page_table_check").
- More folioification work from Matthew Wilcox ("More filesystem folio
conversions for 6.6"), ("Followup folio conversions for zswap"). And
from ZhangPeng ("Convert several functions in page_io.c to use a
folio").
- page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext").
- Baoquan He has converted some architectures to use the GENERIC_IOREMAP
ioremap()/iounmap() code ("mm: ioremap: Convert architectures to take
GENERIC_IOREMAP way").
- Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support
batched/deferred tlb shootdown during page reclamation/migration").
- Better maple tree lockdep checking from Liam Howlett ("More strict
maple tree lockdep"). Liam also developed some efficiency improvements
("Reduce preallocations for maple tree").
- Cleanup and optimization to the secondary IOMMU TLB invalidation, from
Alistair Popple ("Invalidate secondary IOMMU TLB on permission
upgrade").
- Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes
for arm64").
- Kemeng Shi provides some maintenance work on the compaction code ("Two
minor cleanups for compaction").
- Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle most
file-backed faults under the VMA lock").
- Aneesh Kumar contributes code to use the vmemmap optimization for DAX
on ppc64, under some circumstances ("Add support for DAX vmemmap
optimization for ppc64").
- page-ext cleanups from Kemeng Shi ("add page_ext_data to get client
data in page_ext"), ("minor cleanups to page_ext header").
- Some zswap cleanups from Johannes Weiner ("mm: zswap: three
cleanups").
- kmsan cleanups from ZhangPeng ("minor cleanups for kmsan").
- VMA handling cleanups from Kefeng Wang ("mm: convert to
vma_is_initial_heap/stack()").
- DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes:
implement DAMOS tried total bytes file"), ("Extend DAMOS filters for
address ranges and DAMON monitoring targets").
- Compaction work from Kemeng Shi ("Fixes and cleanups to compaction").
- Liam Howlett has improved the maple tree node replacement code
("maple_tree: Change replacement strategy").
- ZhangPeng has a general code cleanup - use the K() macro more widely
("cleanup with helper macro K()").
- Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for memmap
on memory feature on ppc64").
- pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list
in page_alloc"), ("Two minor cleanups for get pageblock migratetype").
- Vishal Moola introduces a memory descriptor for page table tracking,
"struct ptdesc" ("Split ptdesc from struct page").
- memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups
for vm.memfd_noexec").
- MM include file rationalization from Hugh Dickins ("arch: include
asm/cacheflush.h in asm/hugetlb.h").
- THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text
output").
- kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use
object_cache instead of kmemleak_initialized").
- More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor
and _folio_order").
- A VMA locking scalability improvement from Suren Baghdasaryan
("Per-VMA lock support for swap and userfaults").
- pagetable handling cleanups from Matthew Wilcox ("New page table range
API").
- A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop
using page->private on tail pages for THP_SWAP + cleanups").
- Cleanups and speedups to the hugetlb fault handling from Matthew
Wilcox ("Change calling convention for ->huge_fault").
- Matthew Wilcox has also done some maintenance work on the MM subsystem
documentation ("Improve mm documentation").
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Merge tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Some swap cleanups from Ma Wupeng ("fix WARN_ON in
add_to_avail_list")
- Peter Xu has a series (mm/gup: Unify hugetlb, speed up thp") which
reduces the special-case code for handling hugetlb pages in GUP. It
also speeds up GUP handling of transparent hugepages.
- Peng Zhang provides some maple tree speedups ("Optimize the fast path
of mas_store()").
- Sergey Senozhatsky has improved te performance of zsmalloc during
compaction (zsmalloc: small compaction improvements").
- Domenico Cerasuolo has developed additional selftest code for zswap
("selftests: cgroup: add zswap test program").
- xu xin has doe some work on KSM's handling of zero pages. These
changes are mainly to enable the user to better understand the
effectiveness of KSM's treatment of zero pages ("ksm: support
tracking KSM-placed zero-pages").
- Jeff Xu has fixes the behaviour of memfd's
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED sysctl ("mm/memfd: fix sysctl
MEMFD_NOEXEC_SCOPE_NOEXEC_ENFORCED").
- David Howells has fixed an fscache optimization ("mm, netfs, fscache:
Stop read optimisation when folio removed from pagecache").
- Axel Rasmussen has given userfaultfd the ability to simulate memory
poisoning ("add UFFDIO_POISON to simulate memory poisoning with
UFFD").
- Miaohe Lin has contributed some routine maintenance work on the
memory-failure code ("mm: memory-failure: remove unneeded PageHuge()
check").
- Peng Zhang has contributed some maintenance work on the maple tree
code ("Improve the validation for maple tree and some cleanup").
- Hugh Dickins has optimized the collapsing of shmem or file pages into
THPs ("mm: free retracted page table by RCU").
- Jiaqi Yan has a patch series which permits us to use the healthy
subpages within a hardware poisoned huge page for general purposes
("Improve hugetlbfs read on HWPOISON hugepages").
- Kemeng Shi has done some maintenance work on the pagetable-check code
("Remove unused parameters in page_table_check").
- More folioification work from Matthew Wilcox ("More filesystem folio
conversions for 6.6"), ("Followup folio conversions for zswap"). And
from ZhangPeng ("Convert several functions in page_io.c to use a
folio").
- page_ext cleanups from Kemeng Shi ("minor cleanups for page_ext").
- Baoquan He has converted some architectures to use the
GENERIC_IOREMAP ioremap()/iounmap() code ("mm: ioremap: Convert
architectures to take GENERIC_IOREMAP way").
- Anshuman Khandual has optimized arm64 tlb shootdown ("arm64: support
batched/deferred tlb shootdown during page reclamation/migration").
- Better maple tree lockdep checking from Liam Howlett ("More strict
maple tree lockdep"). Liam also developed some efficiency
improvements ("Reduce preallocations for maple tree").
- Cleanup and optimization to the secondary IOMMU TLB invalidation,
from Alistair Popple ("Invalidate secondary IOMMU TLB on permission
upgrade").
- Ryan Roberts fixes some arm64 MM selftest issues ("selftests/mm fixes
for arm64").
- Kemeng Shi provides some maintenance work on the compaction code
("Two minor cleanups for compaction").
- Some reduction in mmap_lock pressure from Matthew Wilcox ("Handle
most file-backed faults under the VMA lock").
- Aneesh Kumar contributes code to use the vmemmap optimization for DAX
on ppc64, under some circumstances ("Add support for DAX vmemmap
optimization for ppc64").
- page-ext cleanups from Kemeng Shi ("add page_ext_data to get client
data in page_ext"), ("minor cleanups to page_ext header").
- Some zswap cleanups from Johannes Weiner ("mm: zswap: three
cleanups").
- kmsan cleanups from ZhangPeng ("minor cleanups for kmsan").
- VMA handling cleanups from Kefeng Wang ("mm: convert to
vma_is_initial_heap/stack()").
- DAMON feature work from SeongJae Park ("mm/damon/sysfs-schemes:
implement DAMOS tried total bytes file"), ("Extend DAMOS filters for
address ranges and DAMON monitoring targets").
- Compaction work from Kemeng Shi ("Fixes and cleanups to compaction").
- Liam Howlett has improved the maple tree node replacement code
("maple_tree: Change replacement strategy").
- ZhangPeng has a general code cleanup - use the K() macro more widely
("cleanup with helper macro K()").
- Aneesh Kumar brings memmap-on-memory to ppc64 ("Add support for
memmap on memory feature on ppc64").
- pagealloc cleanups from Kemeng Shi ("Two minor cleanups for pcp list
in page_alloc"), ("Two minor cleanups for get pageblock
migratetype").
- Vishal Moola introduces a memory descriptor for page table tracking,
"struct ptdesc" ("Split ptdesc from struct page").
- memfd selftest maintenance work from Aleksa Sarai ("memfd: cleanups
for vm.memfd_noexec").
- MM include file rationalization from Hugh Dickins ("arch: include
asm/cacheflush.h in asm/hugetlb.h").
- THP debug output fixes from Hugh Dickins ("mm,thp: fix sloppy text
output").
- kmemleak improvements from Xiaolei Wang ("mm/kmemleak: use
object_cache instead of kmemleak_initialized").
- More folio-related cleanups from Matthew Wilcox ("Remove _folio_dtor
and _folio_order").
- A VMA locking scalability improvement from Suren Baghdasaryan
("Per-VMA lock support for swap and userfaults").
- pagetable handling cleanups from Matthew Wilcox ("New page table
range API").
- A batch of swap/thp cleanups from David Hildenbrand ("mm/swap: stop
using page->private on tail pages for THP_SWAP + cleanups").
- Cleanups and speedups to the hugetlb fault handling from Matthew
Wilcox ("Change calling convention for ->huge_fault").
- Matthew Wilcox has also done some maintenance work on the MM
subsystem documentation ("Improve mm documentation").
* tag 'mm-stable-2023-08-28-18-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (489 commits)
maple_tree: shrink struct maple_tree
maple_tree: clean up mas_wr_append()
secretmem: convert page_is_secretmem() to folio_is_secretmem()
nios2: fix flush_dcache_page() for usage from irq context
hugetlb: add documentation for vma_kernel_pagesize()
mm: add orphaned kernel-doc to the rst files.
mm: fix clean_record_shared_mapping_range kernel-doc
mm: fix get_mctgt_type() kernel-doc
mm: fix kernel-doc warning from tlb_flush_rmaps()
mm: remove enum page_entry_size
mm: allow ->huge_fault() to be called without the mmap_lock held
mm: move PMD_ORDER to pgtable.h
mm: remove checks for pte_index
memcg: remove duplication detection for mem_cgroup_uncharge_swap
mm/huge_memory: work on folio->swap instead of page->private when splitting folio
mm/swap: inline folio_set_swap_entry() and folio_swap_entry()
mm/swap: use dedicated entry for swap in folio
mm/swap: stop using page->private on tail pages for THP_SWAP
selftests/mm: fix WARNING comparing pointer to 0
selftests: cgroup: fix test_kmem_memcg_deletion kernel mem check
...
|
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Matthew Wilcox (Oracle)
|
1d024e7a8d |
mm: remove enum page_entry_size
Remove the unnecessary encoding of page order into an enum and pass the page order directly. That lets us get rid of pe_order(). The switch constructs have to be changed to if/else constructs to prevent GCC from warning on builds with 3-level page tables where PMD_ORDER and PUD_ORDER have the same value. If you are looking at this commit because your driver stopped compiling, look at the previous commit as well and audit your driver to be sure it doesn't depend on mmap_lock being held in its ->huge_fault method. [willy@infradead.org: use "order %u" to match the (non dev_t) style] Link: https://lkml.kernel.org/r/ZOUYekbtTv+n8hYf@casper.infradead.org Link: https://lkml.kernel.org/r/20230818202335.2739663-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
40d49a3c9e |
mm: allow ->huge_fault() to be called without the mmap_lock held
Remove the checks for the VMA lock being held, allowing the page fault path to call into the filesystem instead of retrying with the mmap_lock held. This will improve scalability for DAX page faults. Also update the documentation to match (and fix some other changes that have happened recently). Link: https://lkml.kernel.org/r/20230818202335.2739663-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
bb7dbaafff |
mm: remove checks for pte_index
Since pte_index is always defined, we don't need to check whether it's defined or not. Delete the slow version that doesn't depend on it and remove the #define since nobody needs to test for it. Link: https://lkml.kernel.org/r/20230819031837.3160096-1-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Christian Dietrich <stettberger@dokucode.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
3d2c908768 |
mm/swap: inline folio_set_swap_entry() and folio_swap_entry()
Let's simply work on the folio directly and remove the helpers. Link: https://lkml.kernel.org/r/20230821160849.531668-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Chris Li <chrisl@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
cfeed8ffe5 |
mm/swap: stop using page->private on tail pages for THP_SWAP
Patch series "mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups". This series stops using page->private on tail pages for THP_SWAP, replaces folio->private by folio->swap for swapcache folios, and starts using "new_folio" for tail pages that we are splitting to remove the usage of page->private for swapcache handling completely. This patch (of 4): Let's stop using page->private on tail pages, making it possible to just unconditionally reuse that field in the tail pages of large folios. The remaining usage of the private field for THP_SWAP is in the THP splitting code (mm/huge_memory.c), that we'll handle separately later. Update the THP_SWAP documentation and sanity checks in mm_types.h and __split_huge_page_tail(). [david@redhat.com: stop using page->private on tail pages for THP_SWAP] Link: https://lkml.kernel.org/r/6f0a82a3-6948-20d9-580b-be1dbf415701@redhat.com Link: https://lkml.kernel.org/r/20230821160849.531668-1-david@redhat.com Link: https://lkml.kernel.org/r/20230821160849.531668-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Reviewed-by: Yosry Ahmed <yosryahmed@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: Vitaly Wool <vitaly.wool@konsulko.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
5003a2bdf6 |
mm: call update_mmu_cache_range() in more page fault handling paths
Pass the vm_fault to the architecture to help it make smarter decisions about which PTEs to insert into the TLB. Link: https://lkml.kernel.org/r/20230802151406.3735276-39-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yin Fengwei
|
3bd786f76d |
mm: convert do_set_pte() to set_pte_range()
set_pte_range() allows to setup page table entries for a specific range. It takes advantage of batched rmap update for large folio. It now takes care of calling update_mmu_cache_range(). Link: https://lkml.kernel.org/r/20230802151406.3735276-37-willy@infradead.org Signed-off-by: Yin Fengwei <fengwei.yin@intel.com> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
9f1f5b60e7 |
mm: use flush_icache_pages() in do_set_pmd()
Push the iteration over each page down to the architectures (many can flush the entire THP without iteration). Link: https://lkml.kernel.org/r/20230802151406.3735276-34-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
29a22b9e08 |
mm: handle userfaults under VMA lock
Enable handle_userfault to operate under VMA lock by releasing VMA lock instead of mmap_lock and retrying. Note that FAULT_FLAG_RETRY_NOWAIT should never be used when handling faults under per-VMA lock protection because that would break the assumption that lock is dropped on retry. [surenb@google.com: fix a lockdep issue in vma_assert_write_locked] Link: https://lkml.kernel.org/r/20230712195652.969194-1-surenb@google.com Link: https://lkml.kernel.org/r/20230630211957.1341547-7-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
1235ccd05b |
mm: handle swap page faults under per-VMA lock
When page fault is handled under per-VMA lock protection, all swap page faults are retried with mmap_lock because folio_lock_or_retry has to drop and reacquire mmap_lock if folio could not be immediately locked. Follow the same pattern as mmap_lock to drop per-VMA lock when waiting for folio and retrying once folio is available. With this obstacle removed, enable do_swap_page to operate under per-VMA lock protection. Drivers implementing ops->migrate_to_ram might still rely on mmap_lock, therefore we have to fall back to mmap_lock in that particular case. Note that the only time do_swap_page calls synchronous swap_readpage is when SWP_SYNCHRONOUS_IO is set, which is only set for QUEUE_FLAG_SYNCHRONOUS devices: brd, zram and nvdimms (both btt and pmem). Therefore we don't sleep in this path, and there's no need to drop the mmap or per-VMA lock. Link: https://lkml.kernel.org/r/20230630211957.1341547-6-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Tested-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
fdc724d6aa |
mm: change folio_lock_or_retry to use vm_fault directly
Change folio_lock_or_retry to accept vm_fault struct and return the vm_fault_t directly. Link: https://lkml.kernel.org/r/20230630211957.1341547-5-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Acked-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
4089eef0e6 |
mm: drop per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED
handle_mm_fault returning VM_FAULT_RETRY or VM_FAULT_COMPLETED means mmap_lock has been released. However with per-VMA locks behavior is different and the caller should still release it. To make the rules consistent for the caller, drop the per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED. Currently the only path returning VM_FAULT_RETRY under per-VMA locks is do_swap_page and no path returns VM_FAULT_COMPLETED for now. [willy@infradead.org: fix riscv] Link: https://lkml.kernel.org/r/CAJuCfpE6GWEx1rPBmNpUfoD5o-gNFz9-UFywzCE2PbEGBiVz7g@mail.gmail.com Link: https://lkml.kernel.org/r/20230630211957.1341547-4-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Peter Xu <peterx@redhat.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hillf Danton <hdanton@sina.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Michel Lespinasse <michel@lespinasse.org> Cc: Minchan Kim <minchan@google.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Matthew Wilcox
|
08dff2810e |
mm/memory.c: fix mismerge
Fix a build issue. Link: https://lkml.kernel.org/r/ZNerqcNS4EBJA/2v@casper.infradead.org Fixes: 4aaa60dad4d1 ("mm: allow per-VMA locks on file-backed VMAs") Signed-off-by: Matthew Wilcox <willy@infradead.org> Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202308121909.XNYBtqNI-lkp@intel.com/ Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Vishal Moola (Oracle)
|
6ed1b8a09d |
mm: convert ptlock_free() to use ptdescs
This removes some direct accesses to struct page, working towards splitting out struct ptdesc from struct page. Link: https://lkml.kernel.org/r/20230807230513.102486-11-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Guo Ren <guoren@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonas Bonn <jonas@southpole.se> Cc: Matthew Wilcox <willy@infradead.org> Cc: Palmer Dabbelt <palmer@rivosinc.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Vishal Moola (Oracle)
|
f5ecca06b3 |
mm: convert ptlock_alloc() to use ptdescs
This removes some direct accesses to struct page, working towards splitting out struct ptdesc from struct page. Link: https://lkml.kernel.org/r/20230807230513.102486-6-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Guo Ren <guoren@kernel.org> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Jonas Bonn <jonas@southpole.se> Cc: Matthew Wilcox <willy@infradead.org> Cc: Palmer Dabbelt <palmer@rivosinc.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
e727bfd5e7 |
mm: replace mmap with vma write lock assertions when operating on a vma
Vma write lock assertion always includes mmap write lock assertion and additional vma lock checks when per-VMA locks are enabled. Replace weaker mmap_assert_write_locked() assertions with stronger vma_assert_write_locked() ones when we are operating on a vma which is expected to be locked. Link: https://lkml.kernel.org/r/20230804152724.3090321-4-surenb@google.com Suggested-by: Jann Horn <jannh@google.com> Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Yang Li
|
6e412203ee |
mm/memory.c: fix some kernel-doc comments
Add description of @mas and @tree_end, remove @mt in unmap_vmas(). to silence the warnings: mm/memory.c:1837: warning: Function parameter or member 'mas' not described in 'unmap_vmas' mm/memory.c:1837: warning: Function parameter or member 'tree_end' not described in 'unmap_vmas' mm/memory.c:1837: warning: Excess function parameter 'mt' description in 'unmap_vmas' Link: https://lkml.kernel.org/r/20230727015558.69554-1-yang.lee@linux.alibaba.com Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Reported-by: Abaci Robot <abaci@linux.alibaba.com> Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=5996 Cc: Liam Howlett <liam.howlett@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
|
4542057e18 |
mm: avoid 'might_sleep()' in get_mmap_lock_carefully()
This might_sleep() goes back a long time: it was originally introduced way back when by commit |
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Matthew Wilcox (Oracle)
|
063e60d806 |
mm: handle faults that merely update the accessed bit under the VMA lock
Move FAULT_FLAG_VMA_LOCK check out of handle_pte_fault(). This should have a significant performance improvement for mmaped files. Write faults (on read-only shared pages) still take the mmap lock as we do not want to audit all the implementations of ->pfn_mkwrite() and ->page_mkwrite(). However write-faults on private mappings are handled under the VMA lock. [willy@infradead.org: address "suspicious RCU usage" warning] Link: https://lkml.kernel.org/r/ZMK7jwpI4uD6tKrF@casper.infradead.org Link: https://lkml.kernel.org/r/20230724185410.1124082-11-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
4c2f803abb |
mm: handle swap and NUMA PTE faults under the VMA lock
Move the FAULT_FLAG_VMA_LOCK check down in handle_pte_fault(). This is probably not a huge win in its own right, but is a nicely separable bit from the next patch. Link: https://lkml.kernel.org/r/20230724185410.1124082-10-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
f5617ffeb4 |
mm: run the fault-around code under the VMA lock
The map_pages fs method should be safe to run under the VMA lock instead of the mmap lock. This should have a measurable reduction in contention on the mmap lock. Link: https://lkml.kernel.org/r/20230724185410.1124082-9-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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61a4b8d320 |
mm: move FAULT_FLAG_VMA_LOCK check down from do_fault()
Perform the check at the start of do_read_fault(), do_cow_fault() and do_shared_fault() instead. Should be no performance change from the last commit. Link: https://lkml.kernel.org/r/20230724185410.1124082-8-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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0c2e394ab2 |
mm: move FAULT_FLAG_VMA_LOCK check down in handle_pte_fault()
Call do_pte_missing() under the VMA lock ... then immediately retry in do_fault(). Link: https://lkml.kernel.org/r/20230724185410.1124082-7-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
8f5fd0e1a0 |
mm: handle some PMD faults under the VMA lock
Push the VMA_LOCK check down from __handle_mm_fault() to handle_pte_fault(). Once again, we refuse to call ->huge_fault() with the VMA lock held, but we will wait for a PMD migration entry with the VMA lock held, handle NUMA migration and set the accessed bit. We were already doing this for anonymous VMAs, so it should be safe. Link: https://lkml.kernel.org/r/20230724185410.1124082-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
c4fd825e18 |
mm: handle PUD faults under the VMA lock
Postpone checking the VMA_LOCK flag until we've attempted to handle faults on PUDs. There's a mild upside to this patch in that we'll allocate the page tables while under the VMA lock rather than the mmap lock, reducing the hold time on the mmap lock, since the retry will find the page tables already populated. The real purpose here is to make a commit that shows we don't call ->huge_fault under the VMA lock. We do now handle setting the accessed bit on a PUD fault under the VMA lock, but that doesn't seem likely to be a measurable difference. Link: https://lkml.kernel.org/r/20230724185410.1124082-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
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4ec31152a8 |
mm: move FAULT_FLAG_VMA_LOCK check from handle_mm_fault()
Handle a little more of the page fault path outside the mmap sem. The hugetlb path doesn't need to check whether the VMA is anonymous; the VM_HUGETLB flag is only set on hugetlbfs VMAs. There should be no performance change from the previous commit; this is simply a step to ease bisection of any problems. Link: https://lkml.kernel.org/r/20230724185410.1124082-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
350f6bbca1 |
mm: allow per-VMA locks on file-backed VMAs
Remove the TCP layering violation by allowing per-VMA locks on all VMAs. The fault path will immediately fail in handle_mm_fault(). There may be a small performance reduction from this patch as a little unnecessary work will be done on each page fault. See later patches for the improvement. Link: https://lkml.kernel.org/r/20230724185410.1124082-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Cc: Arjun Roy <arjunroy@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Liam R. Howlett
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fd892593d4 |
mm: change do_vmi_align_munmap() tracking of VMAs to remove
The majority of the calls to munmap a vm range is within a single vma. The maple tree is able to store a single entry at 0, with a size of 1 as a pointer and avoid any allocations. Change do_vmi_align_munmap() to store the VMAs being munmap()'ed into a tree indexed by the count. This will leverage the ability to store the first entry without a node allocation. Storing the entries into a tree by the count and not the vma start and end means changing the functions which iterate over the entries. Update unmap_vmas() and free_pgtables() to take a maple state and a tree end address to support this functionality. Passing through the same maple state to unmap_vmas() and free_pgtables() means the state needs to be reset between calls. This happens in the static unmap_region() and exit_mmap(). Link: https://lkml.kernel.org/r/20230724183157.3939892-4-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Peng Zhang <zhangpeng.00@bytedance.com> Cc: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Alistair Popple
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ec8832d007 |
mmu_notifiers: don't invalidate secondary TLBs as part of mmu_notifier_invalidate_range_end()
Secondary TLBs are now invalidated from the architecture specific TLB invalidation functions. Therefore there is no need to explicitly notify or invalidate as part of the range end functions. This means we can remove mmu_notifier_invalidate_range_end_only() and some of the ptep_*_notify() functions. Link: https://lkml.kernel.org/r/90d749d03cbab256ca0edeb5287069599566d783.1690292440.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Cc: Andrew Donnellan <ajd@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Cc: Frederic Barrat <fbarrat@linux.ibm.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kevin Tian <kevin.tian@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Nicolin Chen <nicolinc@nvidia.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Sean Christopherson <seanjc@google.com> Cc: SeongJae Park <sj@kernel.org> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Zhi Wang <zhi.wang.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Sidhartha Kumar
|
86aa6998ad |
mm/memory: pass folio into do_page_mkwrite()
Saves one implicit call to compound_head(). I'm not sure if I should change the name of the function to do_folio_mkwrite() and update the description comment to reference a folio as the vm_op is still called page_mkwrite. Link: https://lkml.kernel.org/r/20230711053544.156617-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Axel Rasmussen
|
af19487f00 |
mm: make PTE_MARKER_SWAPIN_ERROR more general
Patch series "add UFFDIO_POISON to simulate memory poisoning with UFFD", v4. This series adds a new userfaultfd feature, UFFDIO_POISON. See commit 4 for a detailed description of the feature. This patch (of 8): Future patches will reuse PTE_MARKER_SWAPIN_ERROR to implement UFFDIO_POISON, so make some various preparations for that: First, rename it to just PTE_MARKER_POISONED. The "SWAPIN" can be confusing since we're going to re-use it for something not really related to swap. This can be particularly confusing for things like hugetlbfs, which doesn't support swap whatsoever. Also rename some various helper functions. Next, fix pte marker copying for hugetlbfs. Previously, it would WARN on seeing a PTE_MARKER_SWAPIN_ERROR, since hugetlbfs doesn't support swap. But, since we're going to re-use it, we want it to go ahead and copy it just like non-hugetlbfs memory does today. Since the code to do this is more complicated now, pull it out into a helper which can be re-used in both places. While we're at it, also make it slightly more explicit in its handling of e.g. uffd wp markers. For non-hugetlbfs page faults, instead of returning VM_FAULT_SIGBUS for an error entry, return VM_FAULT_HWPOISON. For most cases this change doesn't matter, e.g. a userspace program would receive a SIGBUS either way. But for UFFDIO_POISON, this change will let KVM guests get an MCE out of the box, instead of giving a SIGBUS to the hypervisor and requiring it to somehow inject an MCE. Finally, for hugetlbfs faults, handle PTE_MARKER_POISONED, and return VM_FAULT_HWPOISON_LARGE in such cases. Note that this can't happen today because the lack of swap support means we'll never end up with such a PTE anyway, but this behavior will be needed once such entries *can* show up via UFFDIO_POISON. Link: https://lkml.kernel.org/r/20230707215540.2324998-1-axelrasmussen@google.com Link: https://lkml.kernel.org/r/20230707215540.2324998-2-axelrasmussen@google.com Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Brian Geffon <bgeffon@google.com> Cc: Christian Brauner <brauner@kernel.org> Cc: David Hildenbrand <david@redhat.com> Cc: Gaosheng Cui <cuigaosheng1@huawei.com> Cc: Huang, Ying <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: James Houghton <jthoughton@google.com> Cc: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Cc: Jiaqi Yan <jiaqiyan@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nadav Amit <namit@vmware.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: T.J. Alumbaugh <talumbau@google.com> Cc: Yu Zhao <yuzhao@google.com> Cc: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Sidhartha Kumar
|
22d1e68f5a |
mm/memory: convert do_read_fault() to use folios
Saves one implicit call to compound_head(). Link: https://lkml.kernel.org/r/20230706163847.403202-4-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Sidhartha Kumar
|
6f609b7e37 |
mm/memory: convert do_shared_fault() to folios
Saves three implicit calls to compound_head(). Link: https://lkml.kernel.org/r/20230706163847.403202-3-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Sidhartha Kumar
|
5a97858b51 |
mm/memory: convert wp_page_shared() to use folios
Saves six implicit calls to compound_head(). Link: https://lkml.kernel.org/r/20230706163847.403202-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Sidhartha Kumar
|
3d243659d9 |
mm/memory: convert do_page_mkwrite() to use folios
Saves one implicit call to compound_head(). Link: https://lkml.kernel.org/r/20230706163847.403202-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: ZhangPeng <zhangpeng362@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yang Li
|
809ef83ccb |
mm: fix some kernel-doc comments
Add description of @mm_wr_locked and @mm. to silence the warnings: mm/memory.c:1716: warning: Function parameter or member 'mm_wr_locked' not described in 'unmap_vmas' mm/memory.c:5110: warning: Function parameter or member 'mm' not described in 'mm_account_fault' Link: https://lkml.kernel.org/r/20230707090034.125511-1-yang.lee@linux.alibaba.com Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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xu xin
|
6080d19f07 |
ksm: add ksm zero pages for each process
As the number of ksm zero pages is not included in ksm_merging_pages per process when enabling use_zero_pages, it's unclear of how many actual pages are merged by KSM. To let users accurately estimate their memory demands when unsharing KSM zero-pages, it's necessary to show KSM zero- pages per process. In addition, it help users to know the actual KSM profit because KSM-placed zero pages are also benefit from KSM. since unsharing zero pages placed by KSM accurately is achieved, then tracking empty pages merging and unmerging is not a difficult thing any longer. Since we already have /proc/<pid>/ksm_stat, just add the information of 'ksm_zero_pages' in it. Link: https://lkml.kernel.org/r/20230613030938.185993-1-yang.yang29@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
xu xin
|
e2942062e0 |
ksm: count all zero pages placed by KSM
As pages_sharing and pages_shared don't include the number of zero pages merged by KSM, we cannot know how many pages are zero pages placed by KSM when enabling use_zero_pages, which leads to KSM not being transparent with all actual merged pages by KSM. In the early days of use_zero_pages, zero-pages was unable to get unshared by the ways like MADV_UNMERGEABLE so it's hard to count how many times one of those zeropages was then unmerged. But now, unsharing KSM-placed zero page accurately has been achieved, so we can easily count both how many times a page full of zeroes was merged with zero-page and how many times one of those pages was then unmerged. and so, it helps to estimate memory demands when each and every shared page could get unshared. So we add ksm_zero_pages under /sys/kernel/mm/ksm/ to show the number of all zero pages placed by KSM. Meanwhile, we update the Documentation. Link: https://lkml.kernel.org/r/20230613030934.185944-1-yang.yang29@zte.com.cn Signed-off-by: xu xin <xu.xin16@zte.com.cn> Acked-by: David Hildenbrand <david@redhat.com> Cc: Claudio Imbrenda <imbrenda@linux.ibm.com> Cc: Xuexin Jiang <jiang.xuexin@zte.com.cn> Reviewed-by: Xiaokai Ran <ran.xiaokai@zte.com.cn> Reviewed-by: Yang Yang <yang.yang29@zte.com.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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ZhangPeng
|
15b4919a1e |
mm: use a folio in fault_dirty_shared_page()
We can replace four implicit calls to compound_head() with one by using folio. Link: https://lkml.kernel.org/r/20230701032853.258697-2-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Sidhartha Kumar
|
87b11f8622 |
mm: increase usage of folio_next_index() helper
Simplify code pattern of 'folio->index + folio_nr_pages(folio)' by using the existing helper folio_next_index(). Link: https://lkml.kernel.org/r/20230627174349.491803-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Suggested-by: Christoph Hellwig <hch@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Kirill A. Shutemov
|
2288397324 |
mm: Fix access_remote_vm() regression on tagged addresses
GDB uses /proc/PID/mem to access memory of the target process. GDB
doesn't untag addresses manually, but relies on kernel to do the right
thing.
mem_rw() of procfs uses access_remote_vm() to get data from the target
process. It worked fine until recent changes in __access_remote_vm()
that now checks if there's VMA at target address using raw address.
Untag the address before looking up the VMA.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Christina Schimpe <christina.schimpe@intel.com>
Fixes:
|
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Jann Horn
|
657b514695 |
mm: lock_vma_under_rcu() must check vma->anon_vma under vma lock
lock_vma_under_rcu() tries to guarantee that __anon_vma_prepare() can't
be called in the VMA-locked page fault path by ensuring that
vma->anon_vma is set.
However, this check happens before the VMA is locked, which means a
concurrent move_vma() can concurrently call unlink_anon_vmas(), which
disassociates the VMA's anon_vma.
This means we can get UAF in the following scenario:
THREAD 1 THREAD 2
======== ========
<page fault>
lock_vma_under_rcu()
rcu_read_lock()
mas_walk()
check vma->anon_vma
mremap() syscall
move_vma()
vma_start_write()
unlink_anon_vmas()
<syscall end>
handle_mm_fault()
__handle_mm_fault()
handle_pte_fault()
do_pte_missing()
do_anonymous_page()
anon_vma_prepare()
__anon_vma_prepare()
find_mergeable_anon_vma()
mas_walk() [looks up VMA X]
munmap() syscall (deletes VMA X)
reusable_anon_vma() [called on freed VMA X]
This is a security bug if you can hit it, although an attacker would
have to win two races at once where the first race window is only a few
instructions wide.
This patch is based on some previous discussion with Linus Torvalds on
the security list.
Cc: stable@vger.kernel.org
Fixes:
|
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Rick Edgecombe
|
e5136e8765 |
mm: Warn on shadow stack memory in wrong vma
The x86 Control-flow Enforcement Technology (CET) feature includes a new type of memory called shadow stack. This shadow stack memory has some unusual properties, which requires some core mm changes to function properly. One sharp edge is that PTEs that are both Write=0 and Dirty=1 are treated as shadow by the CPU, but this combination used to be created by the kernel on x86. Previous patches have changed the kernel to now avoid creating these PTEs unless they are for shadow stack memory. In case any missed corners of the kernel are still creating PTEs like this for non-shadow stack memory, and to catch any re-introductions of the logic, warn if any shadow stack PTEs (Write=0, Dirty=1) are found in non-shadow stack VMAs when they are being zapped. This won't catch transient cases but should have decent coverage. In order to check if a PTE is shadow stack in core mm code, add two arch breakouts arch_check_zapped_pte/pmd(). This will allow shadow stack specific code to be kept in arch/x86. Only do the check if shadow stack is supported by the CPU and configured because in rare cases older CPUs may write Dirty=1 to a Write=0 CPU on older CPUs. This check is handled in pte_shstk()/pmd_shstk(). Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Mark Brown <broonie@kernel.org> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Tested-by: Pengfei Xu <pengfei.xu@intel.com> Tested-by: John Allen <john.allen@amd.com> Tested-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/all/20230613001108.3040476-18-rick.p.edgecombe%40intel.com |
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|
Rick Edgecombe
|
161e393c0f |
mm: Make pte_mkwrite() take a VMA
The x86 Shadow stack feature includes a new type of memory called shadow stack. This shadow stack memory has some unusual properties, which requires some core mm changes to function properly. One of these unusual properties is that shadow stack memory is writable, but only in limited ways. These limits are applied via a specific PTE bit combination. Nevertheless, the memory is writable, and core mm code will need to apply the writable permissions in the typical paths that call pte_mkwrite(). Future patches will make pte_mkwrite() take a VMA, so that the x86 implementation of it can know whether to create regular writable or shadow stack mappings. But there are a couple of challenges to this. Modifying the signatures of each arch pte_mkwrite() implementation would be error prone because some are generated with macros and would need to be re-implemented. Also, some pte_mkwrite() callers operate on kernel memory without a VMA. So this can be done in a three step process. First pte_mkwrite() can be renamed to pte_mkwrite_novma() in each arch, with a generic pte_mkwrite() added that just calls pte_mkwrite_novma(). Next callers without a VMA can be moved to pte_mkwrite_novma(). And lastly, pte_mkwrite() and all callers can be changed to take/pass a VMA. Previous work pte_mkwrite() renamed pte_mkwrite_novma() and converted callers that don't have a VMA were to use pte_mkwrite_novma(). So now change pte_mkwrite() to take a VMA and change the remaining callers to pass a VMA. Apply the same changes for pmd_mkwrite(). No functional change. Suggested-by: David Hildenbrand <david@redhat.com> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Acked-by: David Hildenbrand <david@redhat.com> Link: https://lore.kernel.org/all/20230613001108.3040476-4-rick.p.edgecombe%40intel.com |
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Peter Collingbourne
|
6dca4ac6fc |
mm: call arch_swap_restore() from do_swap_page()
Commit |
||
|
Linus Torvalds
|
eee9c708cc |
gup: avoid stack expansion warning for known-good case
In commit
|
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|
Linus Torvalds
|
9471f1f2f5 |
Merge branch 'expand-stack'
This modifies our user mode stack expansion code to always take the
mmap_lock for writing before modifying the VM layout.
It's actually something we always technically should have done, but
because we didn't strictly need it, we were being lazy ("opportunistic"
sounds so much better, doesn't it?) about things, and had this hack in
place where we would extend the stack vma in-place without doing the
proper locking.
And it worked fine. We just needed to change vm_start (or, in the case
of grow-up stacks, vm_end) and together with some special ad-hoc locking
using the anon_vma lock and the mm->page_table_lock, it all was fairly
straightforward.
That is, it was all fine until Ruihan Li pointed out that now that the
vma layout uses the maple tree code, we *really* don't just change
vm_start and vm_end any more, and the locking really is broken. Oops.
It's not actually all _that_ horrible to fix this once and for all, and
do proper locking, but it's a bit painful. We have basically three
different cases of stack expansion, and they all work just a bit
differently:
- the common and obvious case is the page fault handling. It's actually
fairly simple and straightforward, except for the fact that we have
something like 24 different versions of it, and you end up in a maze
of twisty little passages, all alike.
- the simplest case is the execve() code that creates a new stack.
There are no real locking concerns because it's all in a private new
VM that hasn't been exposed to anybody, but lockdep still can end up
unhappy if you get it wrong.
- and finally, we have GUP and page pinning, which shouldn't really be
expanding the stack in the first place, but in addition to execve()
we also use it for ptrace(). And debuggers do want to possibly access
memory under the stack pointer and thus need to be able to expand the
stack as a special case.
None of these cases are exactly complicated, but the page fault case in
particular is just repeated slightly differently many many times. And
ia64 in particular has a fairly complicated situation where you can have
both a regular grow-down stack _and_ a special grow-up stack for the
register backing store.
So to make this slightly more manageable, the bulk of this series is to
first create a helper function for the most common page fault case, and
convert all the straightforward architectures to it.
Thus the new 'lock_mm_and_find_vma()' helper function, which ends up
being used by x86, arm, powerpc, mips, riscv, alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa. So we not only convert more
than half the architectures, we now have more shared code and avoid some
of those twisty little passages.
And largely due to this common helper function, the full diffstat of
this series ends up deleting more lines than it adds.
That still leaves eight architectures (ia64, m68k, microblaze, openrisc,
parisc, s390, sparc64 and um) that end up doing 'expand_stack()'
manually because they are doing something slightly different from the
normal pattern. Along with the couple of special cases in execve() and
GUP.
So there's a couple of patches that first create 'locked' helper
versions of the stack expansion functions, so that there's a obvious
path forward in the conversion. The execve() case is then actually
pretty simple, and is a nice cleanup from our old "grow-up stackls are
special, because at execve time even they grow down".
The #ifdef CONFIG_STACK_GROWSUP in that code just goes away, because
it's just more straightforward to write out the stack expansion there
manually, instead od having get_user_pages_remote() do it for us in some
situations but not others and have to worry about locking rules for GUP.
And the final step is then to just convert the remaining odd cases to a
new world order where 'expand_stack()' is called with the mmap_lock held
for reading, but where it might drop it and upgrade it to a write, only
to return with it held for reading (in the success case) or with it
completely dropped (in the failure case).
In the process, we remove all the stack expansion from GUP (where
dropping the lock wouldn't be ok without special rules anyway), and add
it in manually to __access_remote_vm() for ptrace().
Thanks to Adrian Glaubitz and Frank Scheiner who tested the ia64 cases.
Everything else here felt pretty straightforward, but the ia64 rules for
stack expansion are really quite odd and very different from everything
else. Also thanks to Vegard Nossum who caught me getting one of those
odd conditions entirely the wrong way around.
Anyway, I think I want to actually move all the stack expansion code to
a whole new file of its own, rather than have it split up between
mm/mmap.c and mm/memory.c, but since this will have to be backported to
the initial maple tree vma introduction anyway, I tried to keep the
patches _fairly_ minimal.
Also, while I don't think it's valid to expand the stack from GUP, the
final patch in here is a "warn if some crazy GUP user wants to try to
expand the stack" patch. That one will be reverted before the final
release, but it's left to catch any odd cases during the merge window
and release candidates.
Reported-by: Ruihan Li <lrh2000@pku.edu.cn>
* branch 'expand-stack':
gup: add warning if some caller would seem to want stack expansion
mm: always expand the stack with the mmap write lock held
execve: expand new process stack manually ahead of time
mm: make find_extend_vma() fail if write lock not held
powerpc/mm: convert coprocessor fault to lock_mm_and_find_vma()
mm/fault: convert remaining simple cases to lock_mm_and_find_vma()
arm/mm: Convert to using lock_mm_and_find_vma()
riscv/mm: Convert to using lock_mm_and_find_vma()
mips/mm: Convert to using lock_mm_and_find_vma()
powerpc/mm: Convert to using lock_mm_and_find_vma()
arm64/mm: Convert to using lock_mm_and_find_vma()
mm: make the page fault mmap locking killable
mm: introduce new 'lock_mm_and_find_vma()' page fault helper
|
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|
Linus Torvalds
|
3a8a670eee |
Networking changes for 6.5.
Core
----
- Rework the sendpage & splice implementations. Instead of feeding
data into sockets page by page extend sendmsg handlers to support
taking a reference on the data, controlled by a new flag called
MSG_SPLICE_PAGES. Rework the handling of unexpected-end-of-file
to invoke an additional callback instead of trying to predict what
the right combination of MORE/NOTLAST flags is.
Remove the MSG_SENDPAGE_NOTLAST flag completely.
- Implement SCM_PIDFD, a new type of CMSG type analogous to
SCM_CREDENTIALS, but it contains pidfd instead of plain pid.
- Enable socket busy polling with CONFIG_RT.
- Improve reliability and efficiency of reporting for ref_tracker.
- Auto-generate a user space C library for various Netlink families.
Protocols
---------
- Allow TCP to shrink the advertised window when necessary, prevent
sk_rcvbuf auto-tuning from growing the window all the way up to
tcp_rmem[2].
- Use per-VMA locking for "page-flipping" TCP receive zerocopy.
- Prepare TCP for device-to-device data transfers, by making sure
that payloads are always attached to skbs as page frags.
- Make the backoff time for the first N TCP SYN retransmissions
linear. Exponential backoff is unnecessarily conservative.
- Create a new MPTCP getsockopt to retrieve all info (MPTCP_FULL_INFO).
- Avoid waking up applications using TLS sockets until we have
a full record.
- Allow using kernel memory for protocol ioctl callbacks, paving
the way to issuing ioctls over io_uring.
- Add nolocalbypass option to VxLAN, forcing packets to be fully
encapsulated even if they are destined for a local IP address.
- Make TCPv4 use consistent hash in TIME_WAIT and SYN_RECV. Ensure
in-kernel ECMP implementation (e.g. Open vSwitch) select the same
link for all packets. Support L4 symmetric hashing in Open vSwitch.
- PPPoE: make number of hash bits configurable.
- Allow DNS to be overwritten by DHCPACK in the in-kernel DHCP client
(ipconfig).
- Add layer 2 miss indication and filtering, allowing higher layers
(e.g. ACL filters) to make forwarding decisions based on whether
packet matched forwarding state in lower devices (bridge).
- Support matching on Connectivity Fault Management (CFM) packets.
- Hide the "link becomes ready" IPv6 messages by demoting their
printk level to debug.
- HSR: don't enable promiscuous mode if device offloads the proto.
- Support active scanning in IEEE 802.15.4.
- Continue work on Multi-Link Operation for WiFi 7.
BPF
---
- Add precision propagation for subprogs and callbacks. This allows
maintaining verification efficiency when subprograms are used,
or in fact passing the verifier at all for complex programs,
especially those using open-coded iterators.
- Improve BPF's {g,s}setsockopt() length handling. Previously BPF
assumed the length is always equal to the amount of written data.
But some protos allow passing a NULL buffer to discover what
the output buffer *should* be, without writing anything.
- Accept dynptr memory as memory arguments passed to helpers.
- Add routing table ID to bpf_fib_lookup BPF helper.
- Support O_PATH FDs in BPF_OBJ_PIN and BPF_OBJ_GET commands.
- Drop bpf_capable() check in BPF_MAP_FREEZE command (used to mark
maps as read-only).
- Show target_{obj,btf}_id in tracing link fdinfo.
- Addition of several new kfuncs (most of the names are self-explanatory):
- Add a set of new dynptr kfuncs: bpf_dynptr_adjust(),
bpf_dynptr_is_null(), bpf_dynptr_is_rdonly(), bpf_dynptr_size()
and bpf_dynptr_clone().
- bpf_task_under_cgroup()
- bpf_sock_destroy() - force closing sockets
- bpf_cpumask_first_and(), rework bpf_cpumask_any*() kfuncs
Netfilter
---------
- Relax set/map validation checks in nf_tables. Allow checking
presence of an entry in a map without using the value.
- Increase ip_vs_conn_tab_bits range for 64BIT builds.
- Allow updating size of a set.
- Improve NAT tuple selection when connection is closing.
Driver API
----------
- Integrate netdev with LED subsystem, to allow configuring HW
"offloaded" blinking of LEDs based on link state and activity
(i.e. packets coming in and out).
- Support configuring rate selection pins of SFP modules.
- Factor Clause 73 auto-negotiation code out of the drivers, provide
common helper routines.
- Add more fool-proof helpers for managing lifetime of MDIO devices
associated with the PCS layer.
- Allow drivers to report advanced statistics related to Time Aware
scheduler offload (taprio).
- Allow opting out of VF statistics in link dump, to allow more VFs
to fit into the message.
- Split devlink instance and devlink port operations.
New hardware / drivers
----------------------
- Ethernet:
- Synopsys EMAC4 IP support (stmmac)
- Marvell 88E6361 8 port (5x1GE + 3x2.5GE) switches
- Marvell 88E6250 7 port switches
- Microchip LAN8650/1 Rev.B0 PHYs
- MediaTek MT7981/MT7988 built-in 1GE PHY driver
- WiFi:
- Realtek RTL8192FU, 2.4 GHz, b/g/n mode, 2T2R, 300 Mbps
- Realtek RTL8723DS (SDIO variant)
- Realtek RTL8851BE
- CAN:
- Fintek F81604
Drivers
-------
- Ethernet NICs:
- Intel (100G, ice):
- support dynamic interrupt allocation
- use meta data match instead of VF MAC addr on slow-path
- nVidia/Mellanox:
- extend link aggregation to handle 4, rather than just 2 ports
- spawn sub-functions without any features by default
- OcteonTX2:
- support HTB (Tx scheduling/QoS) offload
- make RSS hash generation configurable
- support selecting Rx queue using TC filters
- Wangxun (ngbe/txgbe):
- add basic Tx/Rx packet offloads
- add phylink support (SFP/PCS control)
- Freescale/NXP (enetc):
- report TAPRIO packet statistics
- Solarflare/AMD:
- support matching on IP ToS and UDP source port of outer header
- VxLAN and GENEVE tunnel encapsulation over IPv4 or IPv6
- add devlink dev info support for EF10
- Virtual NICs:
- Microsoft vNIC:
- size the Rx indirection table based on requested configuration
- support VLAN tagging
- Amazon vNIC:
- try to reuse Rx buffers if not fully consumed, useful for ARM
servers running with 16kB pages
- Google vNIC:
- support TCP segmentation of >64kB frames
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- enable USXGMII (88E6191X)
- Microchip:
- lan966x: add support for Egress Stage 0 ACL engine
- lan966x: support mapping packet priority to internal switch
priority (based on PCP or DSCP)
- Ethernet PHYs:
- Broadcom PHYs:
- support for Wake-on-LAN for BCM54210E/B50212E
- report LPI counter
- Microsemi PHYs: support RGMII delay configuration (VSC85xx)
- Micrel PHYs: receive timestamp in the frame (LAN8841)
- Realtek PHYs: support optional external PHY clock
- Altera TSE PCS: merge the driver into Lynx PCS which it is
a variant of
- CAN: Kvaser PCIEcan:
- support packet timestamping
- WiFi:
- Intel (iwlwifi):
- major update for new firmware and Multi-Link Operation (MLO)
- configuration rework to drop test devices and split
the different families
- support for segmented PNVM images and power tables
- new vendor entries for PPAG (platform antenna gain) feature
- Qualcomm 802.11ax (ath11k):
- Multiple Basic Service Set Identifier (MBSSID) and
Enhanced MBSSID Advertisement (EMA) support in AP mode
- support factory test mode
- RealTek (rtw89):
- add RSSI based antenna diversity
- support U-NII-4 channels on 5 GHz band
- RealTek (rtl8xxxu):
- AP mode support for 8188f
- support USB RX aggregation for the newer chips
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking changes from Jakub Kicinski:
"WiFi 7 and sendpage changes are the biggest pieces of work for this
release. The latter will definitely require fixes but I think that we
got it to a reasonable point.
Core:
- Rework the sendpage & splice implementations
Instead of feeding data into sockets page by page extend sendmsg
handlers to support taking a reference on the data, controlled by a
new flag called MSG_SPLICE_PAGES
Rework the handling of unexpected-end-of-file to invoke an
additional callback instead of trying to predict what the right
combination of MORE/NOTLAST flags is
Remove the MSG_SENDPAGE_NOTLAST flag completely
- Implement SCM_PIDFD, a new type of CMSG type analogous to
SCM_CREDENTIALS, but it contains pidfd instead of plain pid
- Enable socket busy polling with CONFIG_RT
- Improve reliability and efficiency of reporting for ref_tracker
- Auto-generate a user space C library for various Netlink families
Protocols:
- Allow TCP to shrink the advertised window when necessary, prevent
sk_rcvbuf auto-tuning from growing the window all the way up to
tcp_rmem[2]
- Use per-VMA locking for "page-flipping" TCP receive zerocopy
- Prepare TCP for device-to-device data transfers, by making sure
that payloads are always attached to skbs as page frags
- Make the backoff time for the first N TCP SYN retransmissions
linear. Exponential backoff is unnecessarily conservative
- Create a new MPTCP getsockopt to retrieve all info
(MPTCP_FULL_INFO)
- Avoid waking up applications using TLS sockets until we have a full
record
- Allow using kernel memory for protocol ioctl callbacks, paving the
way to issuing ioctls over io_uring
- Add nolocalbypass option to VxLAN, forcing packets to be fully
encapsulated even if they are destined for a local IP address
- Make TCPv4 use consistent hash in TIME_WAIT and SYN_RECV. Ensure
in-kernel ECMP implementation (e.g. Open vSwitch) select the same
link for all packets. Support L4 symmetric hashing in Open vSwitch
- PPPoE: make number of hash bits configurable
- Allow DNS to be overwritten by DHCPACK in the in-kernel DHCP client
(ipconfig)
- Add layer 2 miss indication and filtering, allowing higher layers
(e.g. ACL filters) to make forwarding decisions based on whether
packet matched forwarding state in lower devices (bridge)
- Support matching on Connectivity Fault Management (CFM) packets
- Hide the "link becomes ready" IPv6 messages by demoting their
printk level to debug
- HSR: don't enable promiscuous mode if device offloads the proto
- Support active scanning in IEEE 802.15.4
- Continue work on Multi-Link Operation for WiFi 7
BPF:
- Add precision propagation for subprogs and callbacks. This allows
maintaining verification efficiency when subprograms are used, or
in fact passing the verifier at all for complex programs,
especially those using open-coded iterators
- Improve BPF's {g,s}setsockopt() length handling. Previously BPF
assumed the length is always equal to the amount of written data.
But some protos allow passing a NULL buffer to discover what the
output buffer *should* be, without writing anything
- Accept dynptr memory as memory arguments passed to helpers
- Add routing table ID to bpf_fib_lookup BPF helper
- Support O_PATH FDs in BPF_OBJ_PIN and BPF_OBJ_GET commands
- Drop bpf_capable() check in BPF_MAP_FREEZE command (used to mark
maps as read-only)
- Show target_{obj,btf}_id in tracing link fdinfo
- Addition of several new kfuncs (most of the names are
self-explanatory):
- Add a set of new dynptr kfuncs: bpf_dynptr_adjust(),
bpf_dynptr_is_null(), bpf_dynptr_is_rdonly(), bpf_dynptr_size()
and bpf_dynptr_clone().
- bpf_task_under_cgroup()
- bpf_sock_destroy() - force closing sockets
- bpf_cpumask_first_and(), rework bpf_cpumask_any*() kfuncs
Netfilter:
- Relax set/map validation checks in nf_tables. Allow checking
presence of an entry in a map without using the value
- Increase ip_vs_conn_tab_bits range for 64BIT builds
- Allow updating size of a set
- Improve NAT tuple selection when connection is closing
Driver API:
- Integrate netdev with LED subsystem, to allow configuring HW
"offloaded" blinking of LEDs based on link state and activity
(i.e. packets coming in and out)
- Support configuring rate selection pins of SFP modules
- Factor Clause 73 auto-negotiation code out of the drivers, provide
common helper routines
- Add more fool-proof helpers for managing lifetime of MDIO devices
associated with the PCS layer
- Allow drivers to report advanced statistics related to Time Aware
scheduler offload (taprio)
- Allow opting out of VF statistics in link dump, to allow more VFs
to fit into the message
- Split devlink instance and devlink port operations
New hardware / drivers:
- Ethernet:
- Synopsys EMAC4 IP support (stmmac)
- Marvell 88E6361 8 port (5x1GE + 3x2.5GE) switches
- Marvell 88E6250 7 port switches
- Microchip LAN8650/1 Rev.B0 PHYs
- MediaTek MT7981/MT7988 built-in 1GE PHY driver
- WiFi:
- Realtek RTL8192FU, 2.4 GHz, b/g/n mode, 2T2R, 300 Mbps
- Realtek RTL8723DS (SDIO variant)
- Realtek RTL8851BE
- CAN:
- Fintek F81604
Drivers:
- Ethernet NICs:
- Intel (100G, ice):
- support dynamic interrupt allocation
- use meta data match instead of VF MAC addr on slow-path
- nVidia/Mellanox:
- extend link aggregation to handle 4, rather than just 2 ports
- spawn sub-functions without any features by default
- OcteonTX2:
- support HTB (Tx scheduling/QoS) offload
- make RSS hash generation configurable
- support selecting Rx queue using TC filters
- Wangxun (ngbe/txgbe):
- add basic Tx/Rx packet offloads
- add phylink support (SFP/PCS control)
- Freescale/NXP (enetc):
- report TAPRIO packet statistics
- Solarflare/AMD:
- support matching on IP ToS and UDP source port of outer
header
- VxLAN and GENEVE tunnel encapsulation over IPv4 or IPv6
- add devlink dev info support for EF10
- Virtual NICs:
- Microsoft vNIC:
- size the Rx indirection table based on requested
configuration
- support VLAN tagging
- Amazon vNIC:
- try to reuse Rx buffers if not fully consumed, useful for ARM
servers running with 16kB pages
- Google vNIC:
- support TCP segmentation of >64kB frames
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- enable USXGMII (88E6191X)
- Microchip:
- lan966x: add support for Egress Stage 0 ACL engine
- lan966x: support mapping packet priority to internal switch
priority (based on PCP or DSCP)
- Ethernet PHYs:
- Broadcom PHYs:
- support for Wake-on-LAN for BCM54210E/B50212E
- report LPI counter
- Microsemi PHYs: support RGMII delay configuration (VSC85xx)
- Micrel PHYs: receive timestamp in the frame (LAN8841)
- Realtek PHYs: support optional external PHY clock
- Altera TSE PCS: merge the driver into Lynx PCS which it is a
variant of
- CAN: Kvaser PCIEcan:
- support packet timestamping
- WiFi:
- Intel (iwlwifi):
- major update for new firmware and Multi-Link Operation (MLO)
- configuration rework to drop test devices and split the
different families
- support for segmented PNVM images and power tables
- new vendor entries for PPAG (platform antenna gain) feature
- Qualcomm 802.11ax (ath11k):
- Multiple Basic Service Set Identifier (MBSSID) and Enhanced
MBSSID Advertisement (EMA) support in AP mode
- support factory test mode
- RealTek (rtw89):
- add RSSI based antenna diversity
- support U-NII-4 channels on 5 GHz band
- RealTek (rtl8xxxu):
- AP mode support for 8188f
- support USB RX aggregation for the newer chips"
* tag 'net-next-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1602 commits)
net: scm: introduce and use scm_recv_unix helper
af_unix: Skip SCM_PIDFD if scm->pid is NULL.
net: lan743x: Simplify comparison
netlink: Add __sock_i_ino() for __netlink_diag_dump().
net: dsa: avoid suspicious RCU usage for synced VLAN-aware MAC addresses
Revert "af_unix: Call scm_recv() only after scm_set_cred()."
phylink: ReST-ify the phylink_pcs_neg_mode() kdoc
libceph: Partially revert changes to support MSG_SPLICE_PAGES
net: phy: mscc: fix packet loss due to RGMII delays
net: mana: use vmalloc_array and vcalloc
net: enetc: use vmalloc_array and vcalloc
ionic: use vmalloc_array and vcalloc
pds_core: use vmalloc_array and vcalloc
gve: use vmalloc_array and vcalloc
octeon_ep: use vmalloc_array and vcalloc
net: usb: qmi_wwan: add u-blox 0x1312 composition
perf trace: fix MSG_SPLICE_PAGES build error
ipvlan: Fix return value of ipvlan_queue_xmit()
netfilter: nf_tables: fix underflow in chain reference counter
netfilter: nf_tables: unbind non-anonymous set if rule construction fails
...
|
||
|
Linus Torvalds
|
6581ccf03e |
mm: fix __access_remote_vm() GUP failure case
Commit |
||
|
Linus Torvalds
|
8d7071af89 |
mm: always expand the stack with the mmap write lock held
This finishes the job of always holding the mmap write lock when extending the user stack vma, and removes the 'write_locked' argument from the vm helper functions again. For some cases, we just avoid expanding the stack at all: drivers and page pinning really shouldn't be extending any stacks. Let's see if any strange users really wanted that. It's worth noting that architectures that weren't converted to the new lock_mm_and_find_vma() helper function are left using the legacy "expand_stack()" function, but it has been changed to drop the mmap_lock and take it for writing while expanding the vma. This makes it fairly straightforward to convert the remaining architectures. As a result of dropping and re-taking the lock, the calling conventions for this function have also changed, since the old vma may no longer be valid. So it will now return the new vma if successful, and NULL - and the lock dropped - if the area could not be extended. Tested-by: Vegard Nossum <vegard.nossum@oracle.com> Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> # ia64 Tested-by: Frank Scheiner <frank.scheiner@web.de> # ia64 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Liam R. Howlett
|
f440fa1ac9 |
mm: make find_extend_vma() fail if write lock not held
Make calls to extend_vma() and find_extend_vma() fail if the write lock is required. To avoid making this a flag-day event, this still allows the old read-locking case for the trivial situations, and passes in a flag to say "is it write-locked". That way write-lockers can say "yes, I'm being careful", and legacy users will continue to work in all the common cases until they have been fully converted to the new world order. Co-Developed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Linus Torvalds
|
eda0047296 |
mm: make the page fault mmap locking killable
This is done as a separate patch from introducing the new lock_mm_and_find_vma() helper, because while it's an obvious change, it's not what x86 used to do in this area. We already abort the page fault on fatal signals anyway, so why should we wait for the mmap lock only to then abort later? With the new helper function that returns without the lock held on failure anyway, this is particularly easy and straightforward. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Linus Torvalds
|
c2508ec5a5 |
mm: introduce new 'lock_mm_and_find_vma()' page fault helper
.. and make x86 use it. This basically extracts the existing x86 "find and expand faulting vma" code, but extends it to also take the mmap lock for writing in case we actually do need to expand the vma. We've historically short-circuited that case, and have some rather ugly special logic to serialize the stack segment expansion (since we only hold the mmap lock for reading) that doesn't match the normal VM locking. That slight violation of locking worked well, right up until it didn't: the maple tree code really does want proper locking even for simple extension of an existing vma. So extract the code for "look up the vma of the fault" from x86, fix it up to do the necessary write locking, and make it available as a helper function for other architectures that can use the common helper. Note: I say "common helper", but it really only handles the normal stack-grows-down case. Which is all architectures except for PA-RISC and IA64. So some rare architectures can't use the helper, but if they care they'll just need to open-code this logic. It's also worth pointing out that this code really would like to have an optimistic "mmap_upgrade_trylock()" to make it quicker to go from a read-lock (for the common case) to taking the write lock (for having to extend the vma) in the normal single-threaded situation where there is no other locking activity. But that _is_ all the very uncommon special case, so while it would be nice to have such an operation, it probably doesn't matter in reality. I did put in the skeleton code for such a possible future expansion, even if it only acts as pseudo-documentation for what we're doing. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
1fec6890bf |
mm: remove references to pagevec
Most of these should just refer to the LRU cache rather than the data structure used to implement the LRU cache. Link: https://lkml.kernel.org/r/20230621164557.3510324-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Ryan Roberts
|
c33c794828 |
mm: ptep_get() conversion
Convert all instances of direct pte_t* dereferencing to instead use ptep_get() helper. This means that by default, the accesses change from a C dereference to a READ_ONCE(). This is technically the correct thing to do since where pgtables are modified by HW (for access/dirty) they are volatile and therefore we should always ensure READ_ONCE() semantics. But more importantly, by always using the helper, it can be overridden by the architecture to fully encapsulate the contents of the pte. Arch code is deliberately not converted, as the arch code knows best. It is intended that arch code (arm64) will override the default with its own implementation that can (e.g.) hide certain bits from the core code, or determine young/dirty status by mixing in state from another source. Conversion was done using Coccinelle: ---- // $ make coccicheck \ // COCCI=ptepget.cocci \ // SPFLAGS="--include-headers" \ // MODE=patch virtual patch @ depends on patch @ pte_t *v; @@ - *v + ptep_get(v) ---- Then reviewed and hand-edited to avoid multiple unnecessary calls to ptep_get(), instead opting to store the result of a single call in a variable, where it is correct to do so. This aims to negate any cost of READ_ONCE() and will benefit arch-overrides that may be more complex. Included is a fix for an issue in an earlier version of this patch that was pointed out by kernel test robot. The issue arose because config MMU=n elides definition of the ptep helper functions, including ptep_get(). HUGETLB_PAGE=n configs still define a simple huge_ptep_clear_flush() for linking purposes, which dereferences the ptep. So when both configs are disabled, this caused a build error because ptep_get() is not defined. Fix by continuing to do a direct dereference when MMU=n. This is safe because for this config the arch code cannot be trying to virtualize the ptes because none of the ptep helpers are defined. Link: https://lkml.kernel.org/r/20230612151545.3317766-4-ryan.roberts@arm.com Reported-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/oe-kbuild-all/202305120142.yXsNEo6H-lkp@intel.com/ Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alex Williamson <alex.williamson@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Dave Airlie <airlied@gmail.com> Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: SeongJae Park <sj@kernel.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Hugh Dickins
|
a92cbb82c8 |
perf/core: allow pte_offset_map() to fail
In rare transient cases, not yet made possible, pte_offset_map() and pte_offet_map_lock() may not find a page table: handle appropriately. [hughd@google.com: __wp_page_copy_user(): don't call update_mmu_tlb() with NULL] Link: https://lkml.kernel.org/r/1a4db221-7872-3594-57ce-42369945ec8d@google.com Link: https://lkml.kernel.org/r/a194441b-63f3-adb6-5964-7ca3171ae7c2@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
|
c7ad08804f |
mm/memory: handle_pte_fault() use pte_offset_map_nolock()
handle_pte_fault() use pte_offset_map_nolock() to get the vmf.ptl which corresponds to vmf.pte, instead of pte_lockptr() being used later, when there's a chance that the pmd entry might have changed, perhaps to none, or to a huge pmd, with no split ptlock in its struct page. Remove its pmd_devmap_trans_unstable() call: pte_offset_map_nolock() will handle that case by failing. Update the "morph" comment above, looking forward to when shmem or file collapse to THP may not take mmap_lock for write (or not at all). do_numa_page() use the vmf->ptl from handle_pte_fault() at first, but refresh it when refreshing vmf->pte. do_swap_page()'s pte_unmap_same() (the thing that takes ptl to verify a two-part PAE orig_pte) use the vmf->ptl from handle_pte_fault() too; but do_swap_page() is also used by anon THP's __collapse_huge_page_swapin(), so adjust that to set vmf->ptl by pte_offset_map_nolock(). Link: https://lkml.kernel.org/r/c1107654-3929-60ac-223e-6877cbb86065@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
|
3db82b9374 |
mm/memory: allow pte_offset_map[_lock]() to fail
copy_pte_range(): use pte_offset_map_nolock(), and allow for it to fail; but with a comment on some further assumptions that are being made there. zap_pte_range() and zap_pmd_range(): adjust their interaction so that a pte_offset_map_lock() failure in zap_pte_range() leads to a retry in zap_pmd_range(); remove call to pmd_none_or_trans_huge_or_clear_bad(). Allow pte_offset_map_lock() to fail in many functions. Update comment on calling pte_alloc() in do_anonymous_page(). Remove redundant calls to pmd_trans_unstable(), pmd_devmap_trans_unstable(), pmd_none() and pmd_bad(); but leave pmd_none_or_clear_bad() calls in free_pmd_range() and copy_pmd_range(), those do simplify the next level down. Link: https://lkml.kernel.org/r/bb548d50-e99a-f29e-eab1-a43bef2a1287@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Hugh Dickins
|
26e1a0c327 |
mm: use pmdp_get_lockless() without surplus barrier()
Patch series "mm: allow pte_offset_map[_lock]() to fail", v2. What is it all about? Some mmap_lock avoidance i.e. latency reduction. Initially just for the case of collapsing shmem or file pages to THPs; but likely to be relied upon later in other contexts e.g. freeing of empty page tables (but that's not work I'm doing). mmap_write_lock avoidance when collapsing to anon THPs? Perhaps, but again that's not work I've done: a quick attempt was not as easy as the shmem/file case. I would much prefer not to have to make these small but wide-ranging changes for such a niche case; but failed to find another way, and have heard that shmem MADV_COLLAPSE's usefulness is being limited by that mmap_write_lock it currently requires. These changes (though of course not these exact patches) have been in Google's data centre kernel for three years now: we do rely upon them. What is this preparatory series about? The current mmap locking will not be enough to guard against that tricky transition between pmd entry pointing to page table, and empty pmd entry, and pmd entry pointing to huge page: pte_offset_map() will have to validate the pmd entry for itself, returning NULL if no page table is there. What to do about that varies: sometimes nearby error handling indicates just to skip it; but in many cases an ACTION_AGAIN or "goto again" is appropriate (and if that risks an infinite loop, then there must have been an oops, or pfn 0 mistaken for page table, before). Given the likely extension to freeing empty page tables, I have not limited this set of changes to a THP config; and it has been easier, and sets a better example, if each site is given appropriate handling: even where deeper study might prove that failure could only happen if the pmd table were corrupted. Several of the patches are, or include, cleanup on the way; and by the end, pmd_trans_unstable() and suchlike are deleted: pte_offset_map() and pte_offset_map_lock() then handle those original races and more. Most uses of pte_lockptr() are deprecated, with pte_offset_map_nolock() taking its place. This patch (of 32): Use pmdp_get_lockless() in preference to READ_ONCE(*pmdp), to get a more reliable result with PAE (or READ_ONCE as before without PAE); and remove the unnecessary extra barrier()s which got left behind in its callers. HOWEVER: Note the small print in linux/pgtable.h, where it was designed specifically for fast GUP, and depends on interrupts being disabled for its full guarantee: most callers which have been added (here and before) do NOT have interrupts disabled, so there is still some need for caution. Link: https://lkml.kernel.org/r/f35279a9-9ac0-de22-d245-591afbfb4dc@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Yu Zhao <yuzhao@google.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Steven Price <steven.price@arm.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Cc: Will Deacon <will@kernel.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zack Rusin <zackr@vmware.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Arjun Roy
|
7a7f094635 |
tcp: Use per-vma locking for receive zerocopy
Per-VMA locking allows us to lock a struct vm_area_struct without taking the process-wide mmap lock in read mode. Consider a process workload where the mmap lock is taken constantly in write mode. In this scenario, all zerocopy receives are periodically blocked during that period of time - though in principle, the memory ranges being used by TCP are not touched by the operations that need the mmap write lock. This results in performance degradation. Now consider another workload where the mmap lock is never taken in write mode, but there are many TCP connections using receive zerocopy that are concurrently receiving. These connections all take the mmap lock in read mode, but this does induce a lot of contention and atomic ops for this process-wide lock. This results in additional CPU overhead caused by contending on the cache line for this lock. However, with per-vma locking, both of these problems can be avoided. As a test, I ran an RPC-style request/response workload with 4KB payloads and receive zerocopy enabled, with 100 simultaneous TCP connections. I measured perf cycles within the find_tcp_vma/mmap_read_lock/mmap_read_unlock codepath, with and without per-vma locking enabled. When using process-wide mmap semaphore read locking, about 1% of measured perf cycles were within this path. With per-VMA locking, this value dropped to about 0.45%. Signed-off-by: Arjun Roy <arjunroy@google.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Ryan Roberts
|
3b65f437d9 |
mm: fix failure to unmap pte on highmem systems
The loser of a race to service a pte for a device private entry in the
swap path previously unlocked the ptl, but failed to unmap the pte. This
only affects highmem systems since unmapping a pte is a noop on
non-highmem systems.
Link: https://lkml.kernel.org/r/20230602092949.545577-5-ryan.roberts@arm.com
Fixes:
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Lorenzo Stoakes
|
ca5e863233 |
mm/gup: remove vmas parameter from get_user_pages_remote()
The only instances of get_user_pages_remote() invocations which used the vmas parameter were for a single page which can instead simply look up the VMA directly. In particular:- - __update_ref_ctr() looked up the VMA but did nothing with it so we simply remove it. - __access_remote_vm() was already using vma_lookup() when the original lookup failed so by doing the lookup directly this also de-duplicates the code. We are able to perform these VMA operations as we already hold the mmap_lock in order to be able to call get_user_pages_remote(). As part of this work we add get_user_page_vma_remote() which abstracts the VMA lookup, error handling and decrementing the page reference count should the VMA lookup fail. This forms part of a broader set of patches intended to eliminate the vmas parameter altogether. [akpm@linux-foundation.org: avoid passing NULL to PTR_ERR] Link: https://lkml.kernel.org/r/d20128c849ecdbf4dd01cc828fcec32127ed939a.1684350871.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> (for arm64) Acked-by: David Hildenbrand <david@redhat.com> Reviewed-by: Janosch Frank <frankja@linux.ibm.com> (for s390) Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christian König <christian.koenig@amd.com> Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Sakari Ailus <sakari.ailus@linux.intel.com> Cc: Sean Christopherson <seanjc@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
53156443a3 |
mm: do not increment pgfault stats when page fault handler retries
If the page fault handler requests a retry, we will count the fault
multiple times. This is a relatively harmless problem as the retry paths
are not often requested, and the only user-visible problem is that the
fault counter will be slightly higher than it should be. Nevertheless,
userspace only took one fault, and should not see the fact that the kernel
had to retry the fault multiple times.
Move page fault accounting into mm_account_fault() and skip incomplete
faults which will be accounted upon completion.
Link: https://lkml.kernel.org/r/20230419175836.3857458-1-surenb@google.com
Fixes:
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Liu Shixin
|
1cb9dc4b47 |
mm: hwpoison: support recovery from HugePage copy-on-write faults
copy-on-write of hugetlb user pages with uncorrectable errors will result in a kernel crash. This is because the copy is performed in kernel mode and in general we can not handle accessing memory with such errors while in kernel mode. Commit |
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ZhangPeng
|
c0e8150e14 |
mm: convert copy_user_huge_page() to copy_user_large_folio()
Replace copy_user_huge_page() with copy_user_large_folio(). copy_user_large_folio() does the same as copy_user_huge_page(), but takes in folios instead of pages. Remove pages_per_huge_page from copy_user_large_folio(), because we can get that from folio_nr_pages(dst). Convert copy_user_gigantic_page() to take in folios. Link: https://lkml.kernel.org/r/20230410133932.32288-6-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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ZhangPeng
|
e87340ca5c |
userfaultfd: convert copy_huge_page_from_user() to copy_folio_from_user()
Replace copy_huge_page_from_user() with copy_folio_from_user(). copy_folio_from_user() does the same as copy_huge_page_from_user(), but takes in a folio instead of a page. Convert page_kaddr to kaddr in copy_folio_from_user() to do indenting cleanup. Link: https://lkml.kernel.org/r/20230410133932.32288-4-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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ZhangPeng
|
0d508c1f0e |
userfaultfd: use kmap_local_page() in copy_huge_page_from_user()
kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page() which is appropriate for any thread local context.[1] Let's replace the kmap() and kmap_atomic() with kmap_local_page() in copy_huge_page_from_user(). When allow_pagefault is false, disable page faults to prevent potential deadlock.[2] [1] https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/ [2] https://lkml.kernel.org/r/20221025220136.2366143-1-ira.weiny@intel.com Link: https://lkml.kernel.org/r/20230410133932.32288-3-zhangpeng362@huawei.com Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nanyong Sun <sunnanyong@huawei.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Andrew Morton
|
e492cd61b9 | sync mm-stable with mm-hotfixes-stable to pick up depended-upon upstream changes | ||
Raghavendra K T
|
fc137c0dda |
sched/numa: enhance vma scanning logic
During Numa scanning make sure only relevant vmas of the tasks are scanned. Before: All the tasks of a process participate in scanning the vma even if they do not access vma in it's lifespan. Now: Except cases of first few unconditional scans, if a process do not touch vma (exluding false positive cases of PID collisions) tasks no longer scan all vma Logic used: 1) 6 bits of PID used to mark active bit in vma numab status during fault to remember PIDs accessing vma. (Thanks Mel) 2) Subsequently in scan path, vma scanning is skipped if current PID had not accessed vma. 3) First two times we do allow unconditional scan to preserve earlier behaviour of scanning. Acknowledgement to Bharata B Rao <bharata@amd.com> for initial patch to store pid information and Peter Zijlstra <peterz@infradead.org> (Usage of test and set bit) Link: https://lkml.kernel.org/r/092f03105c7c1d3450f4636b1ea350407f07640e.1677672277.git.raghavendra.kt@amd.com Signed-off-by: Raghavendra K T <raghavendra.kt@amd.com> Suggested-by: Mel Gorman <mgorman@techsingularity.net> Cc: David Hildenbrand <david@redhat.com> Cc: Disha Talreja <dishaa.talreja@amd.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mike Rapoport <rppt@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Suren Baghdasaryan
|
52f238653e |
mm: introduce per-VMA lock statistics
Add a new CONFIG_PER_VMA_LOCK_STATS config option to dump extra statistics about handling page fault under VMA lock. Link: https://lkml.kernel.org/r/20230227173632.3292573-29-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Suren Baghdasaryan
|
444eeb1743 |
mm: prevent userfaults to be handled under per-vma lock
Due to the possibility of handle_userfault dropping mmap_lock, avoid fault handling under VMA lock and retry holding mmap_lock. This can be handled more gracefully in the future. Link: https://lkml.kernel.org/r/20230227173632.3292573-28-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Suggested-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Suren Baghdasaryan
|
17c05f18e5 |
mm: prevent do_swap_page from handling page faults under VMA lock
Due to the possibility of do_swap_page dropping mmap_lock, abort fault handling under VMA lock and retry holding mmap_lock. This can be handled more gracefully in the future. Link: https://lkml.kernel.org/r/20230227173632.3292573-27-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Laurent Dufour <laurent.dufour@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Suren Baghdasaryan
|
2ac0af1b66 |
mm: fall back to mmap_lock if vma->anon_vma is not yet set
When vma->anon_vma is not set, page fault handler will set it by either reusing anon_vma of an adjacent VMA if VMAs are compatible or by allocating a new one. find_mergeable_anon_vma() walks VMA tree to find a compatible adjacent VMA and that requires not only the faulting VMA to be stable but also the tree structure and other VMAs inside that tree. Therefore locking just the faulting VMA is not enough for this search. Fall back to taking mmap_lock when vma->anon_vma is not set. This situation happens only on the first page fault and should not affect overall performance. Link: https://lkml.kernel.org/r/20230227173632.3292573-25-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Suren Baghdasaryan
|
50ee325372 |
mm: introduce lock_vma_under_rcu to be used from arch-specific code
Introduce lock_vma_under_rcu function to lookup and lock a VMA during page fault handling. When VMA is not found, can't be locked or changes after being locked, the function returns NULL. The lookup is performed under RCU protection to prevent the found VMA from being destroyed before the VMA lock is acquired. VMA lock statistics are updated according to the results. For now only anonymous VMAs can be searched this way. In other cases the function returns NULL. Link: https://lkml.kernel.org/r/20230227173632.3292573-24-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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|
Suren Baghdasaryan
|
98e51a2239 |
mm: conditionally write-lock VMA in free_pgtables
Normally free_pgtables needs to lock affected VMAs except for the case when VMAs were isolated under VMA write-lock. munmap() does just that, isolating while holding appropriate locks and then downgrading mmap_lock and dropping per-VMA locks before freeing page tables. Add a parameter to free_pgtables for such scenario. Link: https://lkml.kernel.org/r/20230227173632.3292573-20-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
58ef47ef7d |
mm: hold the RCU read lock over calls to ->map_pages
Prevent filesystems from doing things which sleep in their map_pages method. This is in preparation for a pagefault path protected only by RCU. Link: https://lkml.kernel.org/r/20230327174515.1811532-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Dave Chinner <david@fromorbit.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
28d8b812e9 |
mm: remove unused vmf_insert_mixed_prot()
Patch series "Remove drm/ttm-specific mm changes".
Functionality was added specifically for the DRM TTM driver to support
mapping memory for VM_MIXEDMAP VMAs with customised protection flags,
however this has now been rolled back as issues were found with this
approach.
This series removes the mm changes too, retaining some of the useful
comments.
This patch (of 3):
The sole user of vmf_insert_mixed_prot(), the drm ttm module, stopped
using this in commit
|
||
|
Lorenzo Stoakes
|
53d36a56d8 |
mm: prefer fault_around_pages to fault_around_bytes
All use of this value is now at page granularity, so specify the variable as such too. This simplifies the logic. We maintain the debugfs entry to ensure that there are no user-visible changes. Link: https://lkml.kernel.org/r/4995bad07fe9baa51c786fa0d81819dddfb57654.1679089214.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Lorenzo Stoakes
|
9042599e81 |
mm: refactor do_fault_around()
Patch series "Refactor do_fault_around()" Refactor do_fault_around() to avoid bitwise tricks and rather difficult to follow logic. Additionally, prefer fault_around_pages to fault_around_bytes as the operations are performed at a base page granularity. This patch (of 2): The existing logic is confusing and fails to abstract a number of bitwise tricks. Use ALIGN_DOWN() to perform alignment, pte_index() to obtain a PTE index and represent the address range using PTE offsets, which naturally make it clear that the operation is intended to occur within only a single PTE and prevent spanning of more than one page table. We rely on the fact that fault_around_bytes will always be page-aligned, at least one page in size, a power of two and that it will not exceed PAGE_SIZE * PTRS_PER_PTE in size (i.e. the address space mapped by a PTE). These are all guaranteed by fault_around_bytes_set(). Link: https://lkml.kernel.org/r/cover.1679089214.git.lstoakes@gmail.com Link: https://lkml.kernel.org/r/d125db1c3665a63b80cea29d56407825482e2262.1679089214.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Peter Xu
|
2bad466cc9 |
mm/uffd: UFFD_FEATURE_WP_UNPOPULATED
Patch series "mm/uffd: Add feature bit UFFD_FEATURE_WP_UNPOPULATED", v4.
The new feature bit makes anonymous memory acts the same as file memory on
userfaultfd-wp in that it'll also wr-protect none ptes.
It can be useful in two cases:
(1) Uffd-wp app that needs to wr-protect none ptes like QEMU snapshot,
so pre-fault can be replaced by enabling this flag and speed up
protections
(2) It helps to implement async uffd-wp mode that Muhammad is working on [1]
It's debatable whether this is the most ideal solution because with the
new feature bit set, wr-protect none pte needs to pre-populate the
pgtables to the last level (PAGE_SIZE). But it seems fine so far to
service either purpose above, so we can leave optimizations for later.
The series brings pte markers to anonymous memory too. There's some
change in the common mm code path in the 1st patch, great to have some eye
looking at it, but hopefully they're still relatively straightforward.
This patch (of 2):
This is a new feature that controls how uffd-wp handles none ptes. When
it's set, the kernel will handle anonymous memory the same way as file
memory, by allowing the user to wr-protect unpopulated ptes.
File memories handles none ptes consistently by allowing wr-protecting of
none ptes because of the unawareness of page cache being exist or not.
For anonymous it was not as persistent because we used to assume that we
don't need protections on none ptes or known zero pages.
One use case of such a feature bit was VM live snapshot, where if without
wr-protecting empty ptes the snapshot can contain random rubbish in the
holes of the anonymous memory, which can cause misbehave of the guest when
the guest OS assumes the pages should be all zeros.
QEMU worked it around by pre-populate the section with reads to fill in
zero page entries before starting the whole snapshot process [1].
Recently there's another need raised on using userfaultfd wr-protect for
detecting dirty pages (to replace soft-dirty in some cases) [2]. In that
case if without being able to wr-protect none ptes by default, the dirty
info can get lost, since we cannot treat every none pte to be dirty (the
current design is identify a page dirty based on uffd-wp bit being
cleared).
In general, we want to be able to wr-protect empty ptes too even for
anonymous.
This patch implements UFFD_FEATURE_WP_UNPOPULATED so that it'll make
uffd-wp handling on none ptes being consistent no matter what the memory
type is underneath. It doesn't have any impact on file memories so far
because we already have pte markers taking care of that. So it only
affects anonymous.
The feature bit is by default off, so the old behavior will be maintained.
Sometimes it may be wanted because the wr-protect of none ptes will
contain overheads not only during UFFDIO_WRITEPROTECT (by applying pte
markers to anonymous), but also on creating the pgtables to store the pte
markers. So there's potentially less chance of using thp on the first
fault for a none pmd or larger than a pmd.
The major implementation part is teaching the whole kernel to understand
pte markers even for anonymously mapped ranges, meanwhile allowing the
UFFDIO_WRITEPROTECT ioctl to apply pte markers for anonymous too when the
new feature bit is set.
Note that even if the patch subject starts with mm/uffd, there're a few
small refactors to major mm path of handling anonymous page faults. But
they should be straightforward.
With WP_UNPOPUATED, application like QEMU can avoid pre-read faults all
the memory before wr-protect during taking a live snapshot. Quotting from
Muhammad's test result here [3] based on a simple program [4]:
(1) With huge page disabled
echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
./uffd_wp_perf
Test DEFAULT: 4
Test PRE-READ: 1111453 (pre-fault 1101011)
Test MADVISE: 278276 (pre-fault 266378)
Test WP-UNPOPULATE: 11712
(2) With Huge page enabled
echo always > /sys/kernel/mm/transparent_hugepage/enabled
./uffd_wp_perf
Test DEFAULT: 4
Test PRE-READ: 22521 (pre-fault 22348)
Test MADVISE: 4909 (pre-fault 4743)
Test WP-UNPOPULATE: 14448
There'll be a great perf boost for no-thp case, while for thp enabled with
extreme case of all-thp-zero WP_UNPOPULATED can be slower than MADVISE,
but that's low possibility in reality, also the overhead was not reduced
but postponed until a follow up write on any huge zero thp, so potentially
it is faster by making the follow up writes slower.
[1] https://lore.kernel.org/all/20210401092226.102804-4-andrey.gruzdev@virtuozzo.com/
[2] https://lore.kernel.org/all/Y+v2HJ8+3i%2FKzDBu@x1n/
[3] https://lore.kernel.org/all/d0eb0a13-16dc-1ac1-653a-78b7273781e3@collabora.com/
[4] https://github.com/xzpeter/clibs/blob/master/uffd-test/uffd-wp-perf.c
[peterx@redhat.com: comment changes, oneliner fix to khugepaged]
Link: https://lkml.kernel.org/r/ZB2/8jPhD3fpx5U8@x1n
Link: https://lkml.kernel.org/r/20230309223711.823547-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20230309223711.823547-2-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Paul Gofman <pgofman@codeweavers.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Alistair Popple
|
7c7b962938 |
mm: take a page reference when removing device exclusive entries
Device exclusive page table entries are used to prevent CPU access to a
page whilst it is being accessed from a device. Typically this is used to
implement atomic operations when the underlying bus does not support
atomic access. When a CPU thread encounters a device exclusive entry it
locks the page and restores the original entry after calling mmu notifiers
to signal drivers that exclusive access is no longer available.
The device exclusive entry holds a reference to the page making it safe to
access the struct page whilst the entry is present. However the fault
handling code does not hold the PTL when taking the page lock. This means
if there are multiple threads faulting concurrently on the device
exclusive entry one will remove the entry whilst others will wait on the
page lock without holding a reference.
This can lead to threads locking or waiting on a folio with a zero
refcount. Whilst mmap_lock prevents the pages getting freed via munmap()
they may still be freed by a migration. This leads to warnings such as
PAGE_FLAGS_CHECK_AT_FREE due to the page being locked when the refcount
drops to zero.
Fix this by trying to take a reference on the folio before locking it.
The code already checks the PTE under the PTL and aborts if the entry is
no longer there. It is also possible the folio has been unmapped, freed
and re-allocated allowing a reference to be taken on an unrelated folio.
This case is also detected by the PTE check and the folio is unlocked
without further changes.
Link: https://lkml.kernel.org/r/20230330012519.804116-1-apopple@nvidia.com
Fixes:
|
||
Gerald Schaefer
|
99c2913363 |
mm: add PTE pointer parameter to flush_tlb_fix_spurious_fault()
s390 can do more fine-grained handling of spurious TLB protection faults, when there also is the PTE pointer available. Therefore, pass on the PTE pointer to flush_tlb_fix_spurious_fault() as an additional parameter. This will add no functional change to other architectures, but those with private flush_tlb_fix_spurious_fault() implementations need to be made aware of the new parameter. Link: https://lkml.kernel.org/r/20230306161548.661740-1-gerald.schaefer@linux.ibm.com Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> [arm64] Acked-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: David Hildenbrand <david@redhat.com> Cc: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
68fa572b50 |
mm: memory: use folio_throttle_swaprate() in do_cow_fault()
Directly use folio_throttle_swaprate() instead of cgroup_throttle_swaprate(). Link: https://lkml.kernel.org/r/20230302115835.105364-7-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
e2bf3e2caa |
mm: memory: use folio_throttle_swaprate() in do_anonymous_page()
Directly use folio_throttle_swaprate() instead of cgroup_throttle_swaprate(). Link: https://lkml.kernel.org/r/20230302115835.105364-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
4d4f75bf32 |
mm: memory: use folio_throttle_swaprate() in wp_page_copy()
Directly use folio_throttle_swaprate() instead of cgroup_throttle_swaprate(). Link: https://lkml.kernel.org/r/20230302115835.105364-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
e601ded424 |
mm: memory: use folio_throttle_swaprate() in page_copy_prealloc()
Directly use folio_throttle_swaprate() instead of cgroup_throttle_swaprate(). Link: https://lkml.kernel.org/r/20230302115835.105364-4-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
4231f84258 |
mm: memory: use folio_throttle_swaprate() in do_swap_page()
Directly use folio_throttle_swaprate() instead of cgroup_throttle_swaprate(). Link: https://lkml.kernel.org/r/20230302115835.105364-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Ma Wupeng
|
d155df53f3 |
x86/mm/pat: clear VM_PAT if copy_p4d_range failed
Syzbot reports a warning in untrack_pfn(). Digging into the root we found
that this is due to memory allocation failure in pmd_alloc_one. And this
failure is produced due to failslab.
In copy_page_range(), memory alloaction for pmd failed. During the error
handling process in copy_page_range(), mmput() is called to remove all
vmas. While untrack_pfn this empty pfn, warning happens.
Here's a simplified flow:
dup_mm
dup_mmap
copy_page_range
copy_p4d_range
copy_pud_range
copy_pmd_range
pmd_alloc
__pmd_alloc
pmd_alloc_one
page = alloc_pages(gfp, 0);
if (!page)
return NULL;
mmput
exit_mmap
unmap_vmas
unmap_single_vma
untrack_pfn
follow_phys
WARN_ON_ONCE(1);
Since this vma is not generate successfully, we can clear flag VM_PAT. In
this case, untrack_pfn() will not be called while cleaning this vma.
Function untrack_pfn_moved() has also been renamed to fit the new logic.
Link: https://lkml.kernel.org/r/20230217025615.1595558-1-mawupeng1@huawei.com
Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
Reported-by: <syzbot+5f488e922d047d8f00cc@syzkaller.appspotmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Peter Xu
|
7a079ba200 |
mm/uffd: fix comment in handling pte markers
The comment is obsolete after
|
||
|
Andrew Morton
|
f67d6b2664 |
Merge branch 'mm-hotfixes-stable' into mm-stable
To pick up depended-upon changes |
||
|
Suren Baghdasaryan
|
68f48381d7 |
mm: introduce __vm_flags_mod and use it in untrack_pfn
There are scenarios when vm_flags can be modified without exclusive mmap_lock, such as: - after VMA was isolated and mmap_lock was downgraded or dropped - in exit_mmap when there are no other mm users and locking is unnecessary Introduce __vm_flags_mod to avoid assertions when the caller takes responsibility for the required locking. Pass a hint to untrack_pfn to conditionally use __vm_flags_mod for flags modification to avoid assertion. Link: https://lkml.kernel.org/r/20230126193752.297968-7-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Oskolkov <posk@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Sebastian Reichel <sebastian.reichel@collabora.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Suren Baghdasaryan
|
1c71222e5f |
mm: replace vma->vm_flags direct modifications with modifier calls
Replace direct modifications to vma->vm_flags with calls to modifier functions to be able to track flag changes and to keep vma locking correctness. [akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo] Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arjun Roy <arjunroy@google.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: David Rientjes <rientjes@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Minchan Kim <minchan@google.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Oskolkov <posk@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Punit Agrawal <punit.agrawal@bytedance.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Soheil Hassas Yeganeh <soheil@google.com> Cc: Song Liu <songliubraving@fb.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Kefeng Wang
|
6b970599e8 |
mm: hwpoison: support recovery from ksm_might_need_to_copy()
When the kernel copies a page from ksm_might_need_to_copy(), but runs into an uncorrectable error, it will crash since poisoned page is consumed by kernel, this is similar to the issue recently fixed by Copy-on-write poison recovery. When an error is detected during the page copy, return VM_FAULT_HWPOISON in do_swap_page(), and install a hwpoison entry in unuse_pte() when swapoff, which help us to avoid system crash. Note, memory failure on a KSM page will be skipped, but still call memory_failure_queue() to be consistent with general memory failure process, and we could support KSM page recovery in the feature. [wangkefeng.wang@huawei.com: enhance unuse_pte(), fix issue found by lkp] Link: https://lkml.kernel.org/r/20221213120523.141588-1-wangkefeng.wang@huawei.com [wangkefeng.wang@huawei.com: update changelog, alter ksm_might_need_to_copy(), restore unlikely() in unuse_pte()] Link: https://lkml.kernel.org/r/20230201074433.96641-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20221209072801.193221-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
14ddee4126 |
mm: use a folio in copy_present_pte()
We still have to keep the page around because we need to know which page in the folio we're copying, but we can replace five implict calls to compound_head() with one. Link: https://lkml.kernel.org/r/20230116191813.2145215-6-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
edf5047058 |
mm: use a folio in copy_pte_range()
Allocate an order-0 folio instead of a page and pass it all the way down the call chain. Removes dozens of calls to compound_head(). Link: https://lkml.kernel.org/r/20230116191813.2145215-5-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
28d41a4863 |
mm: convert wp_page_copy() to use folios
Use new_folio instead of new_page throughout, because we allocated it and know it's an order-0 folio. Most old_page uses become old_folio, but use vmf->page where we need the precise page. Link: https://lkml.kernel.org/r/20230116191813.2145215-4-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
cb3184deef |
mm: convert do_anonymous_page() to use a folio
Removes six calls to compound_head(); some inline and some external. Link: https://lkml.kernel.org/r/20230116191813.2145215-3-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
6bc56a4d85 |
mm: add vma_alloc_zeroed_movable_folio()
Replace alloc_zeroed_user_highpage_movable(). The main difference is returning a folio containing a single page instead of returning the page, but take the opportunity to rename the function to match other allocation functions a little better and rewrite the documentation to place more emphasis on the zeroing rather than the highmem aspect. Link: https://lkml.kernel.org/r/20230116191813.2145215-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
950fe885a8 |
mm: remove __HAVE_ARCH_PTE_SWP_EXCLUSIVE
__HAVE_ARCH_PTE_SWP_EXCLUSIVE is now supported by all architectures that support swp PTEs, so let's drop it. Link: https://lkml.kernel.org/r/20230113171026.582290-27-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Alistair Popple
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7d4a8be0c4 |
mm/mmu_notifier: remove unused mmu_notifier_range_update_to_read_only export
mmu_notifier_range_update_to_read_only() was originally introduced in
commit
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Yu Zhao
|
8788f67814 |
mm: add vma_has_recency()
Add vma_has_recency() to indicate whether a VMA may exhibit temporal
locality that the LRU algorithm relies on.
This function returns false for VMAs marked by VM_SEQ_READ or
VM_RAND_READ. While the former flag indicates linear access, i.e., a
special case of spatial locality, both flags indicate a lack of temporal
locality, i.e., the reuse of an area within a relatively small duration.
"Recency" is chosen over "locality" to avoid confusion between temporal
and spatial localities.
Before this patch, the active/inactive LRU only ignored the accessed bit
from VMAs marked by VM_SEQ_READ. After this patch, the active/inactive
LRU and MGLRU share the same logic: they both ignore the accessed bit if
vma_has_recency() returns false.
For the active/inactive LRU, the following fio test showed a [6, 8]%
increase in IOPS when randomly accessing mapped files under memory
pressure.
kb=$(awk '/MemTotal/ { print $2 }' /proc/meminfo)
kb=$((kb - 8*1024*1024))
modprobe brd rd_nr=1 rd_size=$kb
dd if=/dev/zero of=/dev/ram0 bs=1M
mkfs.ext4 /dev/ram0
mount /dev/ram0 /mnt/
swapoff -a
fio --name=test --directory=/mnt/ --ioengine=mmap --numjobs=8 \
--size=8G --rw=randrw --time_based --runtime=10m \
--group_reporting
The discussion that led to this patch is here [1]. Additional test
results are available in that thread.
[1] https://lore.kernel.org/r/Y31s%2FK8T85jh05wH@google.com/
Link: https://lkml.kernel.org/r/20221230215252.2628425-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Righi <andrea.righi@canonical.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Mike Kravetz
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e9adcfecf5 |
mm: remove zap_page_range and create zap_vma_pages
zap_page_range was originally designed to unmap pages within an address range that could span multiple vmas. While working on [1], it was discovered that all callers of zap_page_range pass a range entirely within a single vma. In addition, the mmu notification call within zap_page range does not correctly handle ranges that span multiple vmas. When crossing a vma boundary, a new mmu_notifier_range_init/end call pair with the new vma should be made. Instead of fixing zap_page_range, do the following: - Create a new routine zap_vma_pages() that will remove all pages within the passed vma. Most users of zap_page_range pass the entire vma and can use this new routine. - For callers of zap_page_range not passing the entire vma, instead call zap_page_range_single(). - Remove zap_page_range. [1] https://lore.kernel.org/linux-mm/20221114235507.294320-2-mike.kravetz@oracle.com/ Link: https://lkml.kernel.org/r/20230104002732.232573-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Suggested-by: Peter Xu <peterx@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> [s390] Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christian Brauner <brauner@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Vishal Moola (Oracle)
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318e9342fb |
mm/memory: add vm_normal_folio()
Patch series "Convert deactivate_page() to folio_deactivate()", v4. Deactivate_page() has already been converted to use folios. This patch series modifies the callers of deactivate_page() to use folios. It also introduces vm_normal_folio() to assist with folio conversions, and converts deactivate_page() to folio_deactivate() which takes in a folio. This patch (of 4): Introduce a wrapper function called vm_normal_folio(). This function calls vm_normal_page() and returns the folio of the page found, or null if no page is found. This function allows callers to get a folio from a pte, which will eventually allow them to completely replace their struct page variables with struct folio instead. Link: https://lkml.kernel.org/r/20221221180848.20774-1-vishal.moola@gmail.com Link: https://lkml.kernel.org/r/20221221180848.20774-2-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Peter Xu
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f1eb1bacfb |
mm/uffd: always wr-protect pte in pte|pmd_mkuffd_wp()
This patch is a cleanup to always wr-protect pte/pmd in mkuffd_wp paths.
The reasons I still think this patch is worthwhile, are:
(1) It is a cleanup already; diffstat tells.
(2) It just feels natural after I thought about this, if the pte is uffd
protected, let's remove the write bit no matter what it was.
(2) Since x86 is the only arch that supports uffd-wp, it also redefines
pte|pmd_mkuffd_wp() in that it should always contain removals of
write bits. It means any future arch that want to implement uffd-wp
should naturally follow this rule too. It's good to make it a
default, even if with vm_page_prot changes on VM_UFFD_WP.
(3) It covers more than vm_page_prot. So no chance of any potential
future "accident" (like pte_mkdirty() sparc64 or loongarch, even
though it just got its pte_mkdirty fixed <1 month ago). It'll be
fairly clear when reading the code too that we don't worry anything
before a pte_mkuffd_wp() on uncertainty of the write bit.
We may call pte_wrprotect() one more time in some paths (e.g. thp split),
but that should be fully local bitop instruction so the overhead should be
negligible.
Although this patch should logically also fix all the known issues on
uffd-wp too recently on page migration (not for numa hint recovery - that
may need another explcit pte_wrprotect), but this is not the plan for that
fix. So no fixes, and stable doesn't need this.
Link: https://lkml.kernel.org/r/20221214201533.1774616-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ives van Hoorne <ives@codesandbox.io>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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Peter Xu
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7e3ce3f8d2 |
mm: fix a few rare cases of using swapin error pte marker
This patch should harden commit |
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Peter Xu
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49d6d7fb63 |
mm/uffd: fix pte marker when fork() without fork event
Patch series "mm: Fixes on pte markers".
Patch 1 resolves the syzkiller report from Pengfei.
Patch 2 further harden pte markers when used with the recent swapin error
markers. The major case is we should persist a swapin error marker after
fork(), so child shouldn't read a corrupted page.
This patch (of 2):
When fork(), dst_vma is not guaranteed to have VM_UFFD_WP even if src may
have it and has pte marker installed. The warning is improper along with
the comment. The right thing is to inherit the pte marker when needed, or
keep the dst pte empty.
A vague guess is this happened by an accident when there's the prior patch
to introduce src/dst vma into this helper during the uffd-wp feature got
developed and I probably messed up in the rebase, since if we replace
dst_vma with src_vma the warning & comment it all makes sense too.
Hugetlb did exactly the right here (copy_hugetlb_page_range()). Fix the
general path.
Reproducer:
https://github.com/xupengfe/syzkaller_logs/blob/main/221208_115556_copy_page_range/repro.c
Bugzilla report: https://bugzilla.kernel.org/show_bug.cgi?id=216808
Link: https://lkml.kernel.org/r/20221214200453.1772655-1-peterx@redhat.com
Link: https://lkml.kernel.org/r/20221214200453.1772655-2-peterx@redhat.com
Fixes:
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David Hildenbrand
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cb8d863313 |
mm: remove VM_FAULT_WRITE
All users -- GUP and KSM -- are gone, let's just remove it. Link: https://lkml.kernel.org/r/20221021101141.84170-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Peter Xu <peterx@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
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8d6a0ac09a |
mm: extend FAULT_FLAG_UNSHARE support to anything in a COW mapping
Extend FAULT_FLAG_UNSHARE to break COW on anything mapped into a COW (i.e., private writable) mapping and adjust the documentation accordingly. FAULT_FLAG_UNSHARE will now also break COW when encountering the shared zeropage, a pagecache page, a PFNMAP, ... inside a COW mapping, by properly replacing the mapped page/pfn by a private copy (an exclusive anonymous page). Note that only do_wp_page() needs care: hugetlb_wp() already handles FAULT_FLAG_UNSHARE correctly. wp_huge_pmd()/wp_huge_pud() also handles it correctly, for example, splitting the huge zeropage on FAULT_FLAG_UNSHARE such that we can handle FAULT_FLAG_UNSHARE on the PTE level. This change is a requirement for reliable long-term R/O pinning in COW mappings. Link: https://lkml.kernel.org/r/20221116102659.70287-9-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
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aea06577a9 |
mm: don't call vm_ops->huge_fault() in wp_huge_pmd()/wp_huge_pud() for private mappings
If we already have a PMD/PUD mapped write-protected in a private mapping and we want to break COW either due to FAULT_FLAG_WRITE or FAULT_FLAG_UNSHARE, there is no need to inform the file system just like on the PTE path. Let's just split (->zap) + fallback in that case. This is a preparation for more generic FAULT_FLAG_UNSHARE support in COW mappings. Link: https://lkml.kernel.org/r/20221116102659.70287-8-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
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b9086fde6d |
mm: rework handling in do_wp_page() based on private vs. shared mappings
We want to extent FAULT_FLAG_UNSHARE support to anything mapped into a COW mapping (pagecache page, zeropage, PFN, ...), not just anonymous pages. Let's prepare for that by handling shared mappings first such that we can handle private mappings last. While at it, use folio-based functions instead of page-based functions where we touch the code either way. Link: https://lkml.kernel.org/r/20221116102659.70287-7-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
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79881fed60 |
mm: add early FAULT_FLAG_WRITE consistency checks
Let's catch abuse of FAULT_FLAG_WRITE early, such that we don't have to care in all other handlers and might get "surprises" if we forget to do so. Write faults without VM_MAYWRITE don't make any sense, and our maybe_mkwrite() logic could have hidden such abuse for now. Write faults without VM_WRITE on something that is not a COW mapping is similarly broken, and e.g., do_wp_page() could end up placing an anonymous page into a shared mapping, which would be bad. This is a preparation for reliable R/O long-term pinning of pages in private mappings, whereby we want to make sure that we will never break COW in a read-only private mapping. Link: https://lkml.kernel.org/r/20221116102659.70287-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
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cdc5021cda |
mm: add early FAULT_FLAG_UNSHARE consistency checks
For now, FAULT_FLAG_UNSHARE only applies to anonymous pages, which implies a COW mapping. Let's hide FAULT_FLAG_UNSHARE early if we're not dealing with a COW mapping, such that we treat it like a read fault as documented and don't have to worry about the flag throughout all fault handlers. While at it, centralize the check for mutual exclusion of FAULT_FLAG_UNSHARE and FAULT_FLAG_WRITE and just drop the check that either flag is set in the WP handler. Link: https://lkml.kernel.org/r/20221116102659.70287-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Alexander Gordeev
|
f036c8184f |
mm: mmu_gather: do not expose delayed_rmap flag
Flag delayed_rmap of 'struct mmu_gather' is rather a private member, but it is still accessed directly. Instead, let the TLB gather code access the flag. Link: https://lkml.kernel.org/r/Y3SWCu6NRaMQ5dbD@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Linus Torvalds
|
5df397dec7 |
mm: delay page_remove_rmap() until after the TLB has been flushed
When we remove a page table entry, we are very careful to only free the
page after we have flushed the TLB, because other CPUs could still be
using the page through stale TLB entries until after the flush.
However, we have removed the rmap entry for that page early, which means
that functions like folio_mkclean() would end up not serializing with the
page table lock because the page had already been made invisible to rmap.
And that is a problem, because while the TLB entry exists, we could end up
with the following situation:
(a) one CPU could come in and clean it, never seeing our mapping of the
page
(b) another CPU could continue to use the stale and dirty TLB entry and
continue to write to said page
resulting in a page that has been dirtied, but then marked clean again,
all while another CPU might have dirtied it some more.
End result: possibly lost dirty data.
This extends our current TLB gather infrastructure to optionally track a
"should I do a delayed page_remove_rmap() for this page after flushing the
TLB". It uses the newly introduced 'encoded page pointer' to do that
without having to keep separate data around.
Note, this is complicated by a couple of issues:
- we want to delay the rmap removal, but not past the page table lock,
because that simplifies the memcg accounting
- only SMP configurations want to delay TLB flushing, since on UP
there are obviously no remote TLBs to worry about, and the page
table lock means there are no preemption issues either
- s390 has its own mmu_gather model that doesn't delay TLB flushing,
and as a result also does not want the delayed rmap. As such, we can
treat S390 like the UP case and use a common fallback for the "no
delays" case.
- we can track an enormous number of pages in our mmu_gather structure,
with MAX_GATHER_BATCH_COUNT batches of MAX_TABLE_BATCH pages each,
all set up to be approximately 10k pending pages.
We do not want to have a huge number of batched pages that we then
need to check for delayed rmap handling inside the page table lock.
Particularly that last point results in a noteworthy detail, where the
normal page batch gathering is limited once we have delayed rmaps pending,
in such a way that only the last batch (the so-called "active batch") in
the mmu_gather structure can have any delayed entries.
NOTE! While the "possibly lost dirty data" sounds catastrophic, for this
all to happen you need to have a user thread doing either madvise() with
MADV_DONTNEED or a full re-mmap() of the area concurrently with another
thread continuing to use said mapping.
So arguably this is about user space doing crazy things, but from a VM
consistency standpoint it's better if we track the dirty bit properly even
when user space goes off the rails.
[akpm@linux-foundation.org: fix UP build, per Linus]
Link: https://lore.kernel.org/all/B88D3073-440A-41C7-95F4-895D3F657EF2@gmail.com/
Link: https://lkml.kernel.org/r/20221109203051.1835763-4-torvalds@linux-foundation.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Hugh Dickins <hughd@google.com>
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Tested-by: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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David Hildenbrand
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6a56ccbcf6 |
mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite
commit |
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Peter Xu
|
15520a3f04 |
mm: use pte markers for swap errors
PTE markers are ideal mechanism for things like SWP_SWAPIN_ERROR. Using a whole swap entry type for this purpose can be an overkill, especially if we already have PTE markers. Define a new bit for swapin error and replace it with pte markers. Then we can safely drop SWP_SWAPIN_ERROR and give one device slot back to swap. We used to have SWP_SWAPIN_ERROR taking the page pfn as part of the swap entry, but it's never used. Neither do I see how it can be useful because normally the swapin failure should not be caused by a bad page but bad swap device. Drop it alongside. Link: https://lkml.kernel.org/r/20221030214151.402274-3-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Huang Ying <ying.huang@intel.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Peter Xu
|
ca92ea3dc5 |
mm: always compile in pte markers
Patch series "mm: Use pte marker for swapin errors". This series uses the pte marker to replace the swapin error swap entry, then we save one more swap entry slot for swap devices. A new pte marker bit is defined. This patch (of 2): The PTE markers code is tiny and now it's enabled for most of the distributions. It's fine to keep it as-is, but to make a broader use of it (e.g. replacing read error swap entry) it needs to be there always otherwise we need special code path to take care of !PTE_MARKER case. It'll be easier just make pte marker always exist. Use this chance to extend its usage to anonymous too by simply touching up some of the old comments, because it'll be used for anonymous pages in the follow up patches. Link: https://lkml.kernel.org/r/20221030214151.402274-1-peterx@redhat.com Link: https://lkml.kernel.org/r/20221030214151.402274-2-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Huang Ying <ying.huang@intel.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Tony Luck
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d302c2398b |
mm, hwpoison: when copy-on-write hits poison, take page offline
Cannot call memory_failure() directly from the fault handler because mmap_lock (and others) are held. It is important, but not urgent, to mark the source page as h/w poisoned and unmap it from other tasks. Use memory_failure_queue() to request a call to memory_failure() for the page with the error. Also provide a stub version for CONFIG_MEMORY_FAILURE=n Link: https://lkml.kernel.org/r/20221021200120.175753-3-tony.luck@intel.com Signed-off-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Shuai Xue <xueshuai@linux.alibaba.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Tony Luck
|
a873dfe103 |
mm, hwpoison: try to recover from copy-on write faults
Patch series "Copy-on-write poison recovery", v3. Part 1 deals with the process that triggered the copy on write fault with a store to a shared read-only page. That process is send a SIGBUS with the usual machine check decoration to specify the virtual address of the lost page, together with the scope. Part 2 sets up to asynchronously take the page with the uncorrected error offline to prevent additional machine check faults. H/t to Miaohe Lin <linmiaohe@huawei.com> and Shuai Xue <xueshuai@linux.alibaba.com> for pointing me to the existing function to queue a call to memory_failure(). On x86 there is some duplicate reporting (because the error is also signalled by the memory controller as well as by the core that triggered the machine check). Console logs look like this: This patch (of 2): If the kernel is copying a page as the result of a copy-on-write fault and runs into an uncorrectable error, Linux will crash because it does not have recovery code for this case where poison is consumed by the kernel. It is easy to set up a test case. Just inject an error into a private page, fork(2), and have the child process write to the page. I wrapped that neatly into a test at: git://git.kernel.org/pub/scm/linux/kernel/git/aegl/ras-tools.git just enable ACPI error injection and run: # ./einj_mem-uc -f copy-on-write Add a new copy_user_highpage_mc() function that uses copy_mc_to_kernel() on architectures where that is available (currently x86 and powerpc). When an error is detected during the page copy, return VM_FAULT_HWPOISON to caller of wp_page_copy(). This propagates up the call stack. Both x86 and powerpc have code in their fault handler to deal with this code by sending a SIGBUS to the application. Note that this patch avoids a system crash and signals the process that triggered the copy-on-write action. It does not take any action for the memory error that is still in the shared page. To handle that a call to memory_failure() is needed. But this cannot be done from wp_page_copy() because it holds mmap_lock(). Perhaps the architecture fault handlers can deal with this loose end in a subsequent patch? On Intel/x86 this loose end will often be handled automatically because the memory controller provides an additional notification of the h/w poison in memory, the handler for this will call memory_failure(). This isn't a 100% solution. If there are multiple errors, not all may be logged in this way. [tony.luck@intel.com: add call to kmsan_unpoison_memory(), per Miaohe Lin] Link: https://lkml.kernel.org/r/20221031201029.102123-2-tony.luck@intel.com Link: https://lkml.kernel.org/r/20221021200120.175753-1-tony.luck@intel.com Link: https://lkml.kernel.org/r/20221021200120.175753-2-tony.luck@intel.com Signed-off-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Alexander Potapenko <glider@google.com> Tested-by: Shuai Xue <xueshuai@linux.alibaba.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Shakeel Butt
|
f1a7941243 |
mm: convert mm's rss stats into percpu_counter
Currently mm_struct maintains rss_stats which are updated on page fault and the unmapping codepaths. For page fault codepath the updates are cached per thread with the batch of TASK_RSS_EVENTS_THRESH which is 64. The reason for caching is performance for multithreaded applications otherwise the rss_stats updates may become hotspot for such applications. However this optimization comes with the cost of error margin in the rss stats. The rss_stats for applications with large number of threads can be very skewed. At worst the error margin is (nr_threads * 64) and we have a lot of applications with 100s of threads, so the error margin can be very high. Internally we had to reduce TASK_RSS_EVENTS_THRESH to 32. Recently we started seeing the unbounded errors for rss_stats for specific applications which use TCP rx0cp. It seems like vm_insert_pages() codepath does not sync rss_stats at all. This patch converts the rss_stats into percpu_counter to convert the error margin from (nr_threads * 64) to approximately (nr_cpus ^ 2). However this conversion enable us to get the accurate stats for situations where accuracy is more important than the cpu cost. This patch does not make such tradeoffs - we can just use percpu_counter_add_local() for the updates and percpu_counter_sum() (or percpu_counter_sync() + percpu_counter_read) for the readers. At the moment the readers are either procfs interface, oom_killer and memory reclaim which I think are not performance critical and should be ok with slow read. However I think we can make that change in a separate patch. Link: https://lkml.kernel.org/r/20221024052841.3291983-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Andrew Morton
|
a38358c934 | Merge branch 'mm-hotfixes-stable' into mm-stable | ||
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Mike Kravetz
|
04ada095dc |
hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
madvise(MADV_DONTNEED) ends up calling zap_page_range() to clear page
tables associated with the address range. For hugetlb vmas,
zap_page_range will call __unmap_hugepage_range_final. However,
__unmap_hugepage_range_final assumes the passed vma is about to be removed
and deletes the vma_lock to prevent pmd sharing as the vma is on the way
out. In the case of madvise(MADV_DONTNEED) the vma remains, but the
missing vma_lock prevents pmd sharing and could potentially lead to issues
with truncation/fault races.
This issue was originally reported here [1] as a BUG triggered in
page_try_dup_anon_rmap. Prior to the introduction of the hugetlb
vma_lock, __unmap_hugepage_range_final cleared the VM_MAYSHARE flag to
prevent pmd sharing. Subsequent faults on this vma were confused as
VM_MAYSHARE indicates a sharable vma, but was not set so page_mapping was
not set in new pages added to the page table. This resulted in pages that
appeared anonymous in a VM_SHARED vma and triggered the BUG.
Address issue by adding a new zap flag ZAP_FLAG_UNMAP to indicate an unmap
call from unmap_vmas(). This is used to indicate the 'final' unmapping of
a hugetlb vma. When called via MADV_DONTNEED, this flag is not set and
the vm_lock is not deleted.
[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/
Link: https://lkml.kernel.org/r/20221114235507.294320-3-mike.kravetz@oracle.com
Fixes:
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||
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Mike Kravetz
|
21b85b0952 |
madvise: use zap_page_range_single for madvise dontneed
This series addresses the issue first reported in [1], and fully described
in patch 2. Patches 1 and 2 address the user visible issue and are tagged
for stable backports.
While exploring solutions to this issue, related problems with mmu
notification calls were discovered. This is addressed in the patch
"hugetlb: remove duplicate mmu notifications:". Since there are no user
visible effects, this third is not tagged for stable backports.
Previous discussions suggested further cleanup by removing the
routine zap_page_range. This is possible because zap_page_range_single
is now exported, and all callers of zap_page_range pass ranges entirely
within a single vma. This work will be done in a later patch so as not
to distract from this bug fix.
[1] https://lore.kernel.org/lkml/CAO4mrfdLMXsao9RF4fUE8-Wfde8xmjsKrTNMNC9wjUb6JudD0g@mail.gmail.com/
This patch (of 2):
Expose the routine zap_page_range_single to zap a range within a single
vma. The madvise routine madvise_dontneed_single_vma can use this routine
as it explicitly operates on a single vma. Also, update the mmu
notification range in zap_page_range_single to take hugetlb pmd sharing
into account. This is required as MADV_DONTNEED supports hugetlb vmas.
Link: https://lkml.kernel.org/r/20221114235507.294320-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20221114235507.294320-2-mike.kravetz@oracle.com
Fixes:
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Alistair Popple
|
4a955bed88 |
mm/memory: return vm_fault_t result from migrate_to_ram() callback
The migrate_to_ram() callback should always succeed, but in rare cases can fail usually returning VM_FAULT_SIGBUS. Commit |
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Peter Xu
|
b12fdbf15f |
Revert "mm/uffd: fix warning without PTE_MARKER_UFFD_WP compiled in"
With " mm/uffd: Fix vma check on userfault for wp" to fix the registration, we'll be safe to remove the macro hacks now. Link: https://lkml.kernel.org/r/20221024193336.1233616-3-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Qi Zheng
|
bce8cb3c04 |
mm: use update_mmu_tlb() on the second thread
As message in commit
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Alistair Popple
|
16ce101db8 |
mm/memory.c: fix race when faulting a device private page
Patch series "Fix several device private page reference counting issues", v2 This series aims to fix a number of page reference counting issues in drivers dealing with device private ZONE_DEVICE pages. These result in use-after-free type bugs, either from accessing a struct page which no longer exists because it has been removed or accessing fields within the struct page which are no longer valid because the page has been freed. During normal usage it is unlikely these will cause any problems. However without these fixes it is possible to crash the kernel from userspace. These crashes can be triggered either by unloading the kernel module or unbinding the device from the driver prior to a userspace task exiting. In modules such as Nouveau it is also possible to trigger some of these issues by explicitly closing the device file-descriptor prior to the task exiting and then accessing device private memory. This involves some minor changes to both PowerPC and AMD GPU code. Unfortunately I lack hardware to test either of those so any help there would be appreciated. The changes mimic what is done in for both Nouveau and hmm-tests though so I doubt they will cause problems. This patch (of 8): When the CPU tries to access a device private page the migrate_to_ram() callback associated with the pgmap for the page is called. However no reference is taken on the faulting page. Therefore a concurrent migration of the device private page can free the page and possibly the underlying pgmap. This results in a race which can crash the kernel due to the migrate_to_ram() function pointer becoming invalid. It also means drivers can't reliably read the zone_device_data field because the page may have been freed with memunmap_pages(). Close the race by getting a reference on the page while holding the ptl to ensure it has not been freed. Unfortunately the elevated reference count will cause the migration required to handle the fault to fail. To avoid this failure pass the faulting page into the migrate_vma functions so that if an elevated reference count is found it can be checked to see if it's expected or not. [mpe@ellerman.id.au: fix build] Link: https://lkml.kernel.org/r/87fsgbf3gh.fsf@mpe.ellerman.id.au Link: https://lkml.kernel.org/r/cover.60659b549d8509ddecafad4f498ee7f03bb23c69.1664366292.git-series.apopple@nvidia.com Link: https://lkml.kernel.org/r/d3e813178a59e565e8d78d9b9a4e2562f6494f90.1664366292.git-series.apopple@nvidia.com Signed-off-by: Alistair Popple <apopple@nvidia.com> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Lyude Paul <lyude@redhat.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Alex Sierra <alex.sierra@amd.com> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Christian König <christian.koenig@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Peter Xu
|
515778e2d7 |
mm/uffd: fix warning without PTE_MARKER_UFFD_WP compiled in
When PTE_MARKER_UFFD_WP not configured, it's still possible to reach pte
marker code and trigger an warning. Add a few CONFIG_PTE_MARKER_UFFD_WP
ifdefs to make sure the code won't be reached when not compiled in.
Link: https://lkml.kernel.org/r/YzeR+R6b4bwBlBHh@x1n
Fixes:
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Mike Kravetz
|
131a79b474 |
hugetlb: fix vma lock handling during split vma and range unmapping
Patch series "hugetlb: fixes for new vma lock series". In review of the series "hugetlb: Use new vma lock for huge pmd sharing synchronization", Miaohe Lin pointed out two key issues: 1) There is a race in the routine hugetlb_unmap_file_folio when locks are dropped and reacquired in the correct order [1]. 2) With the switch to using vma lock for fault/truncate synchronization, we need to make sure lock exists for all VM_MAYSHARE vmas, not just vmas capable of pmd sharing. These two issues are addressed here. In addition, having a vma lock present in all VM_MAYSHARE vmas, uncovered some issues around vma splitting. Those are also addressed. [1] https://lore.kernel.org/linux-mm/01f10195-7088-4462-6def-909549c75ef4@huawei.com/ This patch (of 3): The hugetlb vma lock hangs off the vm_private_data field and is specific to the vma. When vm_area_dup() is called as part of vma splitting, the vma lock pointer is copied to the new vma. This will result in issues such as double freeing of the structure. Update the hugetlb open vm_ops to allocate a new vma lock for the new vma. The routine __unmap_hugepage_range_final unconditionally unset VM_MAYSHARE to prevent subsequent pmd sharing. hugetlb_vma_lock_free attempted to anticipate this by checking both VM_MAYSHARE and VM_SHARED. However, if only VM_MAYSHARE was set we would miss the free. With the introduction of the vma lock, a vma can not participate in pmd sharing if vm_private_data is NULL. Instead of clearing VM_MAYSHARE in __unmap_hugepage_range_final, free the vma lock to prevent sharing. Also, update the sharing code to make sure vma lock is indeed a condition for pmd sharing. hugetlb_vma_lock_free can then key off VM_MAYSHARE and not miss any vmas. Link: https://lkml.kernel.org/r/20221005011707.514612-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20221005011707.514612-2-mike.kravetz@oracle.com Fixes: "hugetlb: add vma based lock for pmd sharing" Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: James Houghton <jthoughton@google.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mina Almasry <almasrymina@google.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Peter Xu <peterx@redhat.com> Cc: Prakash Sangappa <prakash.sangappa@oracle.com> Cc: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Alexander Potapenko
|
b073d7f8ae |
mm: kmsan: maintain KMSAN metadata for page operations
Insert KMSAN hooks that make the necessary bookkeeping changes: - poison page shadow and origins in alloc_pages()/free_page(); - clear page shadow and origins in clear_page(), copy_user_highpage(); - copy page metadata in copy_highpage(), wp_page_copy(); - handle vmap()/vunmap()/iounmap(); Link: https://lkml.kernel.org/r/20220915150417.722975-15-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Marco Elver <elver@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Mike Kravetz
|
40549ba8f8 |
hugetlb: use new vma_lock for pmd sharing synchronization
The new hugetlb vma lock is used to address this race:
Faulting thread Unsharing thread
... ...
ptep = huge_pte_offset()
or
ptep = huge_pte_alloc()
...
i_mmap_lock_write
lock page table
ptep invalid <------------------------ huge_pmd_unshare()
Could be in a previously unlock_page_table
sharing process or worse i_mmap_unlock_write
...
The vma_lock is used as follows:
- During fault processing. The lock is acquired in read mode before
doing a page table lock and allocation (huge_pte_alloc). The lock is
held until code is finished with the page table entry (ptep).
- The lock must be held in write mode whenever huge_pmd_unshare is
called.
Lock ordering issues come into play when unmapping a page from all
vmas mapping the page. The i_mmap_rwsem must be held to search for the
vmas, and the vma lock must be held before calling unmap which will
call huge_pmd_unshare. This is done today in:
- try_to_migrate_one and try_to_unmap_ for page migration and memory
error handling. In these routines we 'try' to obtain the vma lock and
fail to unmap if unsuccessful. Calling routines already deal with the
failure of unmapping.
- hugetlb_vmdelete_list for truncation and hole punch. This routine
also tries to acquire the vma lock. If it fails, it skips the
unmapping. However, we can not have file truncation or hole punch
fail because of contention. After hugetlb_vmdelete_list, truncation
and hole punch call remove_inode_hugepages. remove_inode_hugepages
checks for mapped pages and call hugetlb_unmap_file_page to unmap them.
hugetlb_unmap_file_page is designed to drop locks and reacquire in the
correct order to guarantee unmap success.
Link: https://lkml.kernel.org/r/20220914221810.95771-9-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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Cheng Li
|
14455eabd8 |
mm: use nth_page instead of mem_map_offset mem_map_next
To handle the discontiguous case, mem_map_next() has a parameter named
`offset`. As a function caller, one would be confused why "get next
entry" needs a parameter named "offset". The other drawback of
mem_map_next() is that the callers must take care of the map between
parameter "iter" and "offset", otherwise we may get an hole or duplication
during iteration. So we use nth_page instead of mem_map_next.
And replace mem_map_offset with nth_page() per Matthew's comments.
Link: https://lkml.kernel.org/r/1662708669-9395-1-git-send-email-lic121@chinatelecom.cn
Signed-off-by: Cheng Li <lic121@chinatelecom.cn>
Fixes:
|
||
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Matthew Wilcox (Oracle)
|
19672a9e4a |
mm: convert lock_page_or_retry() to folio_lock_or_retry()
Remove a call to compound_head() in each of the two callers. Link: https://lkml.kernel.org/r/20220902194653.1739778-58-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
3b344157c0 |
mm: remove try_to_free_swap()
All callers have now been converted to folio_free_swap() and we can remove this wrapper. Link: https://lkml.kernel.org/r/20220902194653.1739778-49-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Matthew Wilcox (Oracle)
|
9202d527b7 |
memcg: convert mem_cgroup_swap_full() to take a folio
All callers now have a folio, so convert the function to take a folio. Saves a couple of calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-48-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
a160e5377b |
mm: convert do_swap_page() to use folio_free_swap()
Also convert should_try_to_free_swap() to use a folio. This removes a few calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-47-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Matthew Wilcox (Oracle)
|
e4a2ed9490 |
mm: convert do_wp_page() to use a folio
Saves many calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-42-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
5a423081b2 |
mm: convert do_swap_page() to use swap_cache_get_folio()
Saves a folio->page->folio conversion. Link: https://lkml.kernel.org/r/20220902194653.1739778-38-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
6599591816 |
memcg: convert mem_cgroup_swapin_charge_page() to mem_cgroup_swapin_charge_folio()
All callers now have a folio, so pass it in here and remove an unnecessary call to page_folio(). Link: https://lkml.kernel.org/r/20220902194653.1739778-17-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
d4f9565ae5 |
mm: convert do_swap_page()'s swapcache variable to a folio
The 'swapcache' variable is used to track whether the page is from the swapcache or not. It can do this equally well by being the folio of the page rather than the page itself, and this saves a number of calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-16-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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Matthew Wilcox (Oracle)
|
63ad4add38 |
mm: convert do_swap_page() to use a folio
Removes quite a lot of calls to compound_head(). Link: https://lkml.kernel.org/r/20220902194653.1739778-15-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Liam R. Howlett
|
763ecb0350 |
mm: remove the vma linked list
Replace any vm_next use with vma_find(). Update free_pgtables(), unmap_vmas(), and zap_page_range() to use the maple tree. Use the new free_pgtables() and unmap_vmas() in do_mas_align_munmap(). At the same time, alter the loop to be more compact. Now that free_pgtables() and unmap_vmas() take a maple tree as an argument, rearrange do_mas_align_munmap() to use the new tree to hold the vmas to remove. Remove __vma_link_list() and __vma_unlink_list() as they are exclusively used to update the linked list. Drop linked list update from __insert_vm_struct(). Rework validation of tree as it was depending on the linked list. [yang.lee@linux.alibaba.com: fix one kernel-doc comment] Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=1949 Link: https://lkml.kernel.org/r/20220824021918.94116-1-yang.lee@linux.alibaba.comLink: https://lkml.kernel.org/r/20220906194824.2110408-69-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Signed-off-by: Yang Li <yang.lee@linux.alibaba.com> Tested-by: Yu Zhao <yuzhao@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Aneesh Kumar K.V
|
467b171af8 |
mm/demotion: update node_is_toptier to work with memory tiers
With memory tier support we can have memory only NUMA nodes in the top tier from which we want to avoid promotion tracking NUMA faults. Update node_is_toptier to work with memory tiers. All NUMA nodes are by default top tier nodes. With lower(slower) memory tiers added we consider all memory tiers above a memory tier having CPU NUMA nodes as a top memory tier [sj@kernel.org: include missed header file, memory-tiers.h] Link: https://lkml.kernel.org/r/20220820190720.248704-1-sj@kernel.org [akpm@linux-foundation.org: mm/memory.c needs linux/memory-tiers.h] [aneesh.kumar@linux.ibm.com: make toptier_distance inclusive upper bound of toptiers] Link: https://lkml.kernel.org/r/20220830081457.118960-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220818131042.113280-10-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> Acked-by: Wei Xu <weixugc@google.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Bharata B Rao <bharata@amd.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Hesham Almatary <hesham.almatary@huawei.com> Cc: Jagdish Gediya <jvgediya.oss@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Yang Shi <shy828301@gmail.com> Cc: SeongJae Park <sj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yu Zhao
|
ec1c86b25f |
mm: multi-gen LRU: groundwork
Evictable pages are divided into multiple generations for each lruvec. The youngest generation number is stored in lrugen->max_seq for both anon and file types as they are aged on an equal footing. The oldest generation numbers are stored in lrugen->min_seq[] separately for anon and file types as clean file pages can be evicted regardless of swap constraints. These three variables are monotonically increasing. Generation numbers are truncated into order_base_2(MAX_NR_GENS+1) bits in order to fit into the gen counter in folio->flags. Each truncated generation number is an index to lrugen->lists[]. The sliding window technique is used to track at least MIN_NR_GENS and at most MAX_NR_GENS generations. The gen counter stores a value within [1, MAX_NR_GENS] while a page is on one of lrugen->lists[]. Otherwise it stores 0. There are two conceptually independent procedures: "the aging", which produces young generations, and "the eviction", which consumes old generations. They form a closed-loop system, i.e., "the page reclaim". Both procedures can be invoked from userspace for the purposes of working set estimation and proactive reclaim. These techniques are commonly used to optimize job scheduling (bin packing) in data centers [1][2]. To avoid confusion, the terms "hot" and "cold" will be applied to the multi-gen LRU, as a new convention; the terms "active" and "inactive" will be applied to the active/inactive LRU, as usual. The protection of hot pages and the selection of cold pages are based on page access channels and patterns. There are two access channels: one through page tables and the other through file descriptors. The protection of the former channel is by design stronger because: 1. The uncertainty in determining the access patterns of the former channel is higher due to the approximation of the accessed bit. 2. The cost of evicting the former channel is higher due to the TLB flushes required and the likelihood of encountering the dirty bit. 3. The penalty of underprotecting the former channel is higher because applications usually do not prepare themselves for major page faults like they do for blocked I/O. E.g., GUI applications commonly use dedicated I/O threads to avoid blocking rendering threads. There are also two access patterns: one with temporal locality and the other without. For the reasons listed above, the former channel is assumed to follow the former pattern unless VM_SEQ_READ or VM_RAND_READ is present; the latter channel is assumed to follow the latter pattern unless outlying refaults have been observed [3][4]. The next patch will address the "outlying refaults". Three macros, i.e., LRU_REFS_WIDTH, LRU_REFS_PGOFF and LRU_REFS_MASK, used later are added in this patch to make the entire patchset less diffy. A page is added to the youngest generation on faulting. The aging needs to check the accessed bit at least twice before handing this page over to the eviction. The first check takes care of the accessed bit set on the initial fault; the second check makes sure this page has not been used since then. This protocol, AKA second chance, requires a minimum of two generations, hence MIN_NR_GENS. [1] https://dl.acm.org/doi/10.1145/3297858.3304053 [2] https://dl.acm.org/doi/10.1145/3503222.3507731 [3] https://lwn.net/Articles/495543/ [4] https://lwn.net/Articles/815342/ Link: https://lkml.kernel.org/r/20220918080010.2920238-6-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Barry Song <baohua@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Yu Zhao
|
e1fd09e3d1 |
mm: x86, arm64: add arch_has_hw_pte_young()
Patch series "Multi-Gen LRU Framework", v14. What's new ========== 1. OpenWrt, in addition to Android, Arch Linux Zen, Armbian, ChromeOS, Liquorix, post-factum and XanMod, is now shipping MGLRU on 5.15. 2. Fixed long-tailed direct reclaim latency seen on high-memory (TBs) machines. The old direct reclaim backoff, which tries to enforce a minimum fairness among all eligible memcgs, over-swapped by about (total_mem>>DEF_PRIORITY)-nr_to_reclaim. The new backoff, which pulls the plug on swapping once the target is met, trades some fairness for curtailed latency: https://lore.kernel.org/r/20220918080010.2920238-10-yuzhao@google.com/ 3. Fixed minior build warnings and conflicts. More comments and nits. TLDR ==== The current page reclaim is too expensive in terms of CPU usage and it often makes poor choices about what to evict. This patchset offers an alternative solution that is performant, versatile and straightforward. Patchset overview ================= The design and implementation overview is in patch 14: https://lore.kernel.org/r/20220918080010.2920238-15-yuzhao@google.com/ 01. mm: x86, arm64: add arch_has_hw_pte_young() 02. mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG Take advantage of hardware features when trying to clear the accessed bit in many PTEs. 03. mm/vmscan.c: refactor shrink_node() 04. Revert "include/linux/mm_inline.h: fold __update_lru_size() into its sole caller" Minor refactors to improve readability for the following patches. 05. mm: multi-gen LRU: groundwork Adds the basic data structure and the functions that insert pages to and remove pages from the multi-gen LRU (MGLRU) lists. 06. mm: multi-gen LRU: minimal implementation A minimal implementation without optimizations. 07. mm: multi-gen LRU: exploit locality in rmap Exploits spatial locality to improve efficiency when using the rmap. 08. mm: multi-gen LRU: support page table walks Further exploits spatial locality by optionally scanning page tables. 09. mm: multi-gen LRU: optimize multiple memcgs Optimizes the overall performance for multiple memcgs running mixed types of workloads. 10. mm: multi-gen LRU: kill switch Adds a kill switch to enable or disable MGLRU at runtime. 11. mm: multi-gen LRU: thrashing prevention 12. mm: multi-gen LRU: debugfs interface Provide userspace with features like thrashing prevention, working set estimation and proactive reclaim. 13. mm: multi-gen LRU: admin guide 14. mm: multi-gen LRU: design doc Add an admin guide and a design doc. Benchmark results ================= Independent lab results ----------------------- Based on the popularity of searches [01] and the memory usage in Google's public cloud, the most popular open-source memory-hungry applications, in alphabetical order, are: Apache Cassandra Memcached Apache Hadoop MongoDB Apache Spark PostgreSQL MariaDB (MySQL) Redis An independent lab evaluated MGLRU with the most widely used benchmark suites for the above applications. They posted 960 data points along with kernel metrics and perf profiles collected over more than 500 hours of total benchmark time. Their final reports show that, with 95% confidence intervals (CIs), the above applications all performed significantly better for at least part of their benchmark matrices. On 5.14: 1. Apache Spark [02] took 95% CIs [9.28, 11.19]% and [12.20, 14.93]% less wall time to sort three billion random integers, respectively, under the medium- and the high-concurrency conditions, when overcommitting memory. There were no statistically significant changes in wall time for the rest of the benchmark matrix. 2. MariaDB [03] achieved 95% CIs [5.24, 10.71]% and [20.22, 25.97]% more transactions per minute (TPM), respectively, under the medium- and the high-concurrency conditions, when overcommitting memory. There were no statistically significant changes in TPM for the rest of the benchmark matrix. 3. Memcached [04] achieved 95% CIs [23.54, 32.25]%, [20.76, 41.61]% and [21.59, 30.02]% more operations per second (OPS), respectively, for sequential access, random access and Gaussian (distribution) access, when THP=always; 95% CIs [13.85, 15.97]% and [23.94, 29.92]% more OPS, respectively, for random access and Gaussian access, when THP=never. There were no statistically significant changes in OPS for the rest of the benchmark matrix. 4. MongoDB [05] achieved 95% CIs [2.23, 3.44]%, [6.97, 9.73]% and [2.16, 3.55]% more operations per second (OPS), respectively, for exponential (distribution) access, random access and Zipfian (distribution) access, when underutilizing memory; 95% CIs [8.83, 10.03]%, [21.12, 23.14]% and [5.53, 6.46]% more OPS, respectively, for exponential access, random access and Zipfian access, when overcommitting memory. On 5.15: 5. Apache Cassandra [06] achieved 95% CIs [1.06, 4.10]%, [1.94, 5.43]% and [4.11, 7.50]% more operations per second (OPS), respectively, for exponential (distribution) access, random access and Zipfian (distribution) access, when swap was off; 95% CIs [0.50, 2.60]%, [6.51, 8.77]% and [3.29, 6.75]% more OPS, respectively, for exponential access, random access and Zipfian access, when swap was on. 6. Apache Hadoop [07] took 95% CIs [5.31, 9.69]% and [2.02, 7.86]% less average wall time to finish twelve parallel TeraSort jobs, respectively, under the medium- and the high-concurrency conditions, when swap was on. There were no statistically significant changes in average wall time for the rest of the benchmark matrix. 7. PostgreSQL [08] achieved 95% CI [1.75, 6.42]% more transactions per minute (TPM) under the high-concurrency condition, when swap was off; 95% CIs [12.82, 18.69]% and [22.70, 46.86]% more TPM, respectively, under the medium- and the high-concurrency conditions, when swap was on. There were no statistically significant changes in TPM for the rest of the benchmark matrix. 8. Redis [09] achieved 95% CIs [0.58, 5.94]%, [6.55, 14.58]% and [11.47, 19.36]% more total operations per second (OPS), respectively, for sequential access, random access and Gaussian (distribution) access, when THP=always; 95% CIs [1.27, 3.54]%, [10.11, 14.81]% and [8.75, 13.64]% more total OPS, respectively, for sequential access, random access and Gaussian access, when THP=never. Our lab results --------------- To supplement the above results, we ran the following benchmark suites on 5.16-rc7 and found no regressions [10]. fs_fio_bench_hdd_mq pft fs_lmbench pgsql-hammerdb fs_parallelio redis fs_postmark stream hackbench sysbenchthread kernbench tpcc_spark memcached unixbench multichase vm-scalability mutilate will-it-scale nginx [01] https://trends.google.com [02] https://lore.kernel.org/r/20211102002002.92051-1-bot@edi.works/ [03] https://lore.kernel.org/r/20211009054315.47073-1-bot@edi.works/ [04] https://lore.kernel.org/r/20211021194103.65648-1-bot@edi.works/ [05] https://lore.kernel.org/r/20211109021346.50266-1-bot@edi.works/ [06] https://lore.kernel.org/r/20211202062806.80365-1-bot@edi.works/ [07] https://lore.kernel.org/r/20211209072416.33606-1-bot@edi.works/ [08] https://lore.kernel.org/r/20211218071041.24077-1-bot@edi.works/ [09] https://lore.kernel.org/r/20211122053248.57311-1-bot@edi.works/ [10] https://lore.kernel.org/r/20220104202247.2903702-1-yuzhao@google.com/ Read-world applications ======================= Third-party testimonials ------------------------ Konstantin reported [11]: I have Archlinux with 8G RAM + zswap + swap. While developing, I have lots of apps opened such as multiple LSP-servers for different langs, chats, two browsers, etc... Usually, my system gets quickly to a point of SWAP-storms, where I have to kill LSP-servers, restart browsers to free memory, etc, otherwise the system lags heavily and is barely usable. 1.5 day ago I migrated from 5.11.15 kernel to 5.12 + the LRU patchset, and I started up by opening lots of apps to create memory pressure, and worked for a day like this. Till now I had not a single SWAP-storm, and mind you I got 3.4G in SWAP. I was never getting to the point of 3G in SWAP before without a single SWAP-storm. Vaibhav from IBM reported [12]: In a synthetic MongoDB Benchmark, seeing an average of ~19% throughput improvement on POWER10(Radix MMU + 64K Page Size) with MGLRU patches on top of 5.16 kernel for MongoDB + YCSB across three different request distributions, namely, Exponential, Uniform and Zipfan. Shuang from U of Rochester reported [13]: With the MGLRU, fio achieved 95% CIs [38.95, 40.26]%, [4.12, 6.64]% and [9.26, 10.36]% higher throughput, respectively, for random access, Zipfian (distribution) access and Gaussian (distribution) access, when the average number of jobs per CPU is 1; 95% CIs [42.32, 49.15]%, [9.44, 9.89]% and [20.99, 22.86]% higher throughput, respectively, for random access, Zipfian access and Gaussian access, when the average number of jobs per CPU is 2. Daniel from Michigan Tech reported [14]: With Memcached allocating ~100GB of byte-addressable Optante, performance improvement in terms of throughput (measured as queries per second) was about 10% for a series of workloads. Large-scale deployments ----------------------- We've rolled out MGLRU to tens of millions of ChromeOS users and about a million Android users. Google's fleetwide profiling [15] shows an overall 40% decrease in kswapd CPU usage, in addition to improvements in other UX metrics, e.g., an 85% decrease in the number of low-memory kills at the 75th percentile and an 18% decrease in app launch time at the 50th percentile. The downstream kernels that have been using MGLRU include: 1. Android [16] 2. Arch Linux Zen [17] 3. Armbian [18] 4. ChromeOS [19] 5. Liquorix [20] 6. OpenWrt [21] 7. post-factum [22] 8. XanMod [23] [11] https://lore.kernel.org/r/140226722f2032c86301fbd326d91baefe3d7d23.camel@yandex.ru/ [12] https://lore.kernel.org/r/87czj3mux0.fsf@vajain21.in.ibm.com/ [13] https://lore.kernel.org/r/20220105024423.26409-1-szhai2@cs.rochester.edu/ [14] https://lore.kernel.org/r/CA+4-3vksGvKd18FgRinxhqHetBS1hQekJE2gwco8Ja-bJWKtFw@mail.gmail.com/ [15] https://dl.acm.org/doi/10.1145/2749469.2750392 [16] https://android.com [17] https://archlinux.org [18] https://armbian.com [19] https://chromium.org [20] https://liquorix.net [21] https://openwrt.org [22] https://codeberg.org/pf-kernel [23] https://xanmod.org Summary ======= The facts are: 1. The independent lab results and the real-world applications indicate substantial improvements; there are no known regressions. 2. Thrashing prevention, working set estimation and proactive reclaim work out of the box; there are no equivalent solutions. 3. There is a lot of new code; no smaller changes have been demonstrated similar effects. Our options, accordingly, are: 1. Given the amount of evidence, the reported improvements will likely materialize for a wide range of workloads. 2. Gauging the interest from the past discussions, the new features will likely be put to use for both personal computers and data centers. 3. Based on Google's track record, the new code will likely be well maintained in the long term. It'd be more difficult if not impossible to achieve similar effects with other approaches. This patch (of 14): Some architectures automatically set the accessed bit in PTEs, e.g., x86 and arm64 v8.2. On architectures that do not have this capability, clearing the accessed bit in a PTE usually triggers a page fault following the TLB miss of this PTE (to emulate the accessed bit). Being aware of this capability can help make better decisions, e.g., whether to spread the work out over a period of time to reduce bursty page faults when trying to clear the accessed bit in many PTEs. Note that theoretically this capability can be unreliable, e.g., hotplugged CPUs might be different from builtin ones. Therefore it should not be used in architecture-independent code that involves correctness, e.g., to determine whether TLB flushes are required (in combination with the accessed bit). Link: https://lkml.kernel.org/r/20220918080010.2920238-1-yuzhao@google.com Link: https://lkml.kernel.org/r/20220918080010.2920238-2-yuzhao@google.com Signed-off-by: Yu Zhao <yuzhao@google.com> Reviewed-by: Barry Song <baohua@kernel.org> Acked-by: Brian Geffon <bgeffon@google.com> Acked-by: Jan Alexander Steffens (heftig) <heftig@archlinux.org> Acked-by: Oleksandr Natalenko <oleksandr@natalenko.name> Acked-by: Steven Barrett <steven@liquorix.net> Acked-by: Suleiman Souhlal <suleiman@google.com> Acked-by: Will Deacon <will@kernel.org> Tested-by: Daniel Byrne <djbyrne@mtu.edu> Tested-by: Donald Carr <d@chaos-reins.com> Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Tested-by: Konstantin Kharlamov <Hi-Angel@yandex.ru> Tested-by: Shuang Zhai <szhai2@cs.rochester.edu> Tested-by: Sofia Trinh <sofia.trinh@edi.works> Tested-by: Vaibhav Jain <vaibhav@linux.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-arm-kernel@lists.infradead.org Cc: Matthew Wilcox <willy@infradead.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michael Larabel <Michael@MichaelLarabel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Qi Zheng <zhengqi.arch@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Andrew Morton
|
6d751329e7 | Merge branch 'mm-hotfixes-stable' into mm-stable | ||
Sergei Antonov
|
70427f6e9e |
mm: bring back update_mmu_cache() to finish_fault()
Running this test program on ARMv4 a few times (sometimes just once)
reproduces the bug.
int main()
{
unsigned i;
char paragon[SIZE];
void* ptr;
memset(paragon, 0xAA, SIZE);
ptr = mmap(NULL, SIZE, PROT_READ | PROT_WRITE,
MAP_ANON | MAP_SHARED, -1, 0);
if (ptr == MAP_FAILED) return 1;
printf("ptr = %p\n", ptr);
for (i=0;i<10000;i++){
memset(ptr, 0xAA, SIZE);
if (memcmp(ptr, paragon, SIZE)) {
printf("Unexpected bytes on iteration %u!!!\n", i);
break;
}
}
munmap(ptr, SIZE);
}
In the "ptr" buffer there appear runs of zero bytes which are aligned
by 16 and their lengths are multiple of 16.
Linux v5.11 does not have the bug, "git bisect" finds the first bad commit:
|
||
Huang Ying
|
33024536ba |
memory tiering: hot page selection with hint page fault latency
Patch series "memory tiering: hot page selection", v4.
To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory nodes need to be identified.
Essentially, the original NUMA balancing implementation selects the mostly
recently accessed (MRU) pages to promote. But this isn't a perfect
algorithm to identify the hot pages. Because the pages with quite low
access frequency may be accessed eventually given the NUMA balancing page
table scanning period could be quite long (e.g. 60 seconds). So in this
patchset, we implement a new hot page identification algorithm based on
the latency between NUMA balancing page table scanning and hint page
fault. Which is a kind of mostly frequently accessed (MFU) algorithm.
In NUMA balancing memory tiering mode, if there are hot pages in slow
memory node and cold pages in fast memory node, we need to promote/demote
hot/cold pages between the fast and cold memory nodes.
A choice is to promote/demote as fast as possible. But the CPU cycles and
memory bandwidth consumed by the high promoting/demoting throughput will
hurt the latency of some workload because of accessing inflating and slow
memory bandwidth contention.
A way to resolve this issue is to restrict the max promoting/demoting
throughput. It will take longer to finish the promoting/demoting. But
the workload latency will be better. This is implemented in this patchset
as the page promotion rate limit mechanism.
The promotion hot threshold is workload and system configuration
dependent. So in this patchset, a method to adjust the hot threshold
automatically is implemented. The basic idea is to control the number of
the candidate promotion pages to match the promotion rate limit.
We used the pmbench memory accessing benchmark tested the patchset on a
2-socket server system with DRAM and PMEM installed. The test results are
as follows,
pmbench score promote rate
(accesses/s) MB/s
------------- ------------
base 146887704.1 725.6
hot selection 165695601.2 544.0
rate limit 162814569.8 165.2
auto adjustment 170495294.0 136.9
From the results above,
With hot page selection patch [1/3], the pmbench score increases about
12.8%, and promote rate (overhead) decreases about 25.0%, compared with
base kernel.
With rate limit patch [2/3], pmbench score decreases about 1.7%, and
promote rate decreases about 69.6%, compared with hot page selection
patch.
With threshold auto adjustment patch [3/3], pmbench score increases about
4.7%, and promote rate decrease about 17.1%, compared with rate limit
patch.
Baolin helped to test the patchset with MySQL on a machine which contains
1 DRAM node (30G) and 1 PMEM node (126G).
sysbench /usr/share/sysbench/oltp_read_write.lua \
......
--tables=200 \
--table-size=1000000 \
--report-interval=10 \
--threads=16 \
--time=120
The tps can be improved about 5%.
This patch (of 3):
To optimize page placement in a memory tiering system with NUMA balancing,
the hot pages in the slow memory node need to be identified. Essentially,
the original NUMA balancing implementation selects the mostly recently
accessed (MRU) pages to promote. But this isn't a perfect algorithm to
identify the hot pages. Because the pages with quite low access frequency
may be accessed eventually given the NUMA balancing page table scanning
period could be quite long (e.g. 60 seconds). The most frequently
accessed (MFU) algorithm is better.
So, in this patch we implemented a better hot page selection algorithm.
Which is based on NUMA balancing page table scanning and hint page fault
as follows,
- When the page tables of the processes are scanned to change PTE/PMD
to be PROT_NONE, the current time is recorded in struct page as scan
time.
- When the page is accessed, hint page fault will occur. The scan
time is gotten from the struct page. And The hint page fault
latency is defined as
hint page fault time - scan time
The shorter the hint page fault latency of a page is, the higher the
probability of their access frequency to be higher. So the hint page
fault latency is a better estimation of the page hot/cold.
It's hard to find some extra space in struct page to hold the scan time.
Fortunately, we can reuse some bits used by the original NUMA balancing.
NUMA balancing uses some bits in struct page to store the page accessing
CPU and PID (referring to page_cpupid_xchg_last()). Which is used by the
multi-stage node selection algorithm to avoid to migrate pages shared
accessed by the NUMA nodes back and forth. But for pages in the slow
memory node, even if they are shared accessed by multiple NUMA nodes, as
long as the pages are hot, they need to be promoted to the fast memory
node. So the accessing CPU and PID information are unnecessary for the
slow memory pages. We can reuse these bits in struct page to record the
scan time. For the fast memory pages, these bits are used as before.
For the hot threshold, the default value is 1 second, which works well in
our performance test. All pages with hint page fault latency < hot
threshold will be considered hot.
It's hard for users to determine the hot threshold. So we don't provide a
kernel ABI to set it, just provide a debugfs interface for advanced users
to experiment. We will continue to work on a hot threshold automatic
adjustment mechanism.
The downside of the above method is that the response time to the workload
hot spot changing may be much longer. For example,
- A previous cold memory area becomes hot
- The hint page fault will be triggered. But the hint page fault
latency isn't shorter than the hot threshold. So the pages will
not be promoted.
- When the memory area is scanned again, maybe after a scan period,
the hint page fault latency measured will be shorter than the hot
threshold and the pages will be promoted.
To mitigate this, if there are enough free space in the fast memory node,
the hot threshold will not be used, all pages will be promoted upon the
hint page fault for fast response.
Thanks Zhong Jiang reported and tested the fix for a bug when disabling
memory tiering mode dynamically.
Link: https://lkml.kernel.org/r/20220713083954.34196-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220713083954.34196-2-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Wei Xu <weixugc@google.com>
Cc: osalvador <osalvador@suse.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Zhong Jiang <zhongjiang-ali@linux.alibaba.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
Zach O'Keefe
|
a7f4e6e4c4 |
mm/thp: add flag to enforce sysfs THP in hugepage_vma_check()
MADV_COLLAPSE is not coupled to the kernel-oriented sysfs THP settings[1]. hugepage_vma_check() is the authority on determining if a VMA is eligible for THP allocation/collapse, and currently enforces the sysfs THP settings. Add a flag to disable these checks. For now, only apply this arg to anon and file, which use /sys/kernel/transparent_hugepage/enabled. We can expand this to shmem, which uses /sys/kernel/transparent_hugepage/shmem_enabled, later. Use this flag in collapse_pte_mapped_thp() where previously the VMA flags passed to hugepage_vma_check() were OR'd with VM_HUGEPAGE to elide the VM_HUGEPAGE check in "madvise" THP mode. Prior to "mm: khugepaged: check THP flag in hugepage_vma_check()", this check also didn't check "never" THP mode. As such, this restores the previous behavior of collapse_pte_mapped_thp() where sysfs THP settings are ignored. See comment in code for justification why this is OK. [1] https://lore.kernel.org/linux-mm/CAAa6QmQxay1_=Pmt8oCX2-Va18t44FV-Vs-WsQt_6+qBks4nZA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20220706235936.2197195-8-zokeefe@google.com Signed-off-by: Zach O'Keefe <zokeefe@google.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: Chris Kennelly <ckennelly@google.com> Cc: Chris Zankel <chris@zankel.net> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Helge Deller <deller@gmx.de> Cc: Hugh Dickins <hughd@google.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Pavel Begunkov <asml.silence@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com> Cc: SeongJae Park <sj@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zi Yan <ziy@nvidia.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Linus Torvalds
|
6614a3c316 |
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve latency
and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place
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Merge tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Most of the MM queue. A few things are still pending.
Liam's maple tree rework didn't make it. This has resulted in a few
other minor patch series being held over for next time.
Multi-gen LRU still isn't merged as we were waiting for mapletree to
stabilize. The current plan is to merge MGLRU into -mm soon and to
later reintroduce mapletree, with a view to hopefully getting both
into 6.1-rc1.
Summary:
- The usual batches of cleanups from Baoquan He, Muchun Song, Miaohe
Lin, Yang Shi, Anshuman Khandual and Mike Rapoport
- Some kmemleak fixes from Patrick Wang and Waiman Long
- DAMON updates from SeongJae Park
- memcg debug/visibility work from Roman Gushchin
- vmalloc speedup from Uladzislau Rezki
- more folio conversion work from Matthew Wilcox
- enhancements for coherent device memory mapping from Alex Sierra
- addition of shared pages tracking and CoW support for fsdax, from
Shiyang Ruan
- hugetlb optimizations from Mike Kravetz
- Mel Gorman has contributed some pagealloc changes to improve
latency and realtime behaviour.
- mprotect soft-dirty checking has been improved by Peter Xu
- Many other singleton patches all over the place"
[ XFS merge from hell as per Darrick Wong in
https://lore.kernel.org/all/YshKnxb4VwXycPO8@magnolia/ ]
* tag 'mm-stable-2022-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (282 commits)
tools/testing/selftests/vm/hmm-tests.c: fix build
mm: Kconfig: fix typo
mm: memory-failure: convert to pr_fmt()
mm: use is_zone_movable_page() helper
hugetlbfs: fix inaccurate comment in hugetlbfs_statfs()
hugetlbfs: cleanup some comments in inode.c
hugetlbfs: remove unneeded header file
hugetlbfs: remove unneeded hugetlbfs_ops forward declaration
hugetlbfs: use helper macro SZ_1{K,M}
mm: cleanup is_highmem()
mm/hmm: add a test for cross device private faults
selftests: add soft-dirty into run_vmtests.sh
selftests: soft-dirty: add test for mprotect
mm/mprotect: fix soft-dirty check in can_change_pte_writable()
mm: memcontrol: fix potential oom_lock recursion deadlock
mm/gup.c: fix formatting in check_and_migrate_movable_page()
xfs: fail dax mount if reflink is enabled on a partition
mm/memcontrol.c: remove the redundant updating of stats_flush_threshold
userfaultfd: don't fail on unrecognized features
hugetlb_cgroup: fix wrong hugetlb cgroup numa stat
...
|
||
Miaohe Lin
|
4d8ff64097 |
mm: remove unneeded PageAnon check in restore_exclusive_pte()
When code reaches here, the page must be !PageAnon. There's no need to check PageAnon again. Remove it. Link: https://lkml.kernel.org/r/20220716081816.10752-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Miaohe Lin
|
0f0b6931ff |
mm: remove obsolete comment in do_fault_around()
Since commit
|
||
|
Linus Torvalds
|
39c3c396f8 |
Thirteen hotfixes, Eight are cc:stable and the remainder are for post-5.18
issues or are too minor to warrant backporting -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCYuCV7gAKCRDdBJ7gKXxA jrK2AQDeoayQKXJFTcEltKAUTooXM/BoRf+O3ti/xrSWpwta8wEAjaBIJ8e7UlCj g+p6u/pd38f226ldzI5w3bIBSPCbnwU= =3rO0 -----END PGP SIGNATURE----- Merge tag 'mm-hotfixes-stable-2022-07-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc fixes from Andrew Morton: "Thirteen hotfixes. Eight are cc:stable and the remainder are for post-5.18 issues or are too minor to warrant backporting" * tag 'mm-hotfixes-stable-2022-07-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: mailmap: update Gao Xiang's email addresses userfaultfd: provide properly masked address for huge-pages Revert "ocfs2: mount shared volume without ha stack" hugetlb: fix memoryleak in hugetlb_mcopy_atomic_pte fs: sendfile handles O_NONBLOCK of out_fd ntfs: fix use-after-free in ntfs_ucsncmp() secretmem: fix unhandled fault in truncate mm/hugetlb: separate path for hwpoison entry in copy_hugetlb_page_range() mm: fix missing wake-up event for FSDAX pages mm: fix page leak with multiple threads mapping the same page mailmap: update Seth Forshee's email address tmpfs: fix the issue that the mount and remount results are inconsistent. mm: kfence: apply kmemleak_ignore_phys on early allocated pool |
||
|
Qi Zheng
|
cdb281e638 |
mm: fix NULL pointer dereference in wp_page_reuse()
The vmf->page can be NULL when the wp_page_reuse() is invoked by
wp_pfn_shared(), it will cause the following panic:
BUG: kernel NULL pointer dereference, address: 000000000000008
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 18 PID: 923 Comm: Xorg Not tainted 5.19.0-rc8.bm.1-amd64 #263
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g14
RIP: 0010:_compound_head+0x0/0x40
[...]
Call Trace:
wp_page_reuse+0x1c/0xa0
do_wp_page+0x1a5/0x3f0
__handle_mm_fault+0x8cf/0xd20
handle_mm_fault+0xd5/0x2a0
do_user_addr_fault+0x1d0/0x680
exc_page_fault+0x78/0x170
asm_exc_page_fault+0x22/0x30
To fix it, this patch performs a NULL pointer check before dereferencing
the vmf->page.
Fixes:
|
||
Josef Bacik
|
3fe2895cfe |
mm: fix page leak with multiple threads mapping the same page
We have an application with a lot of threads that use a shared mmap backed by tmpfs mounted with -o huge=within_size. This application started leaking loads of huge pages when we upgraded to a recent kernel. Using the page ref tracepoints and a BPF program written by Tejun Heo we were able to determine that these pages would have multiple refcounts from the page fault path, but when it came to unmap time we wouldn't drop the number of refs we had added from the faults. I wrote a reproducer that mmap'ed a file backed by tmpfs with -o huge=always, and then spawned 20 threads all looping faulting random offsets in this map, while using madvise(MADV_DONTNEED) randomly for huge page aligned ranges. This very quickly reproduced the problem. The problem here is that we check for the case that we have multiple threads faulting in a range that was previously unmapped. One thread maps the PMD, the other thread loses the race and then returns 0. However at this point we already have the page, and we are no longer putting this page into the processes address space, and so we leak the page. We actually did the correct thing prior to |
||
|
Mike Kravetz
|
bcd51a3c67 |
hugetlb: lazy page table copies in fork()
Lazy page table copying at fork time was introduced with commit
|
||
Yang Shi
|
7da4e2cb8b |
mm: thp: kill __transhuge_page_enabled()
The page fault path checks THP eligibility with __transhuge_page_enabled() which does the similar thing as hugepage_vma_check(), so use hugepage_vma_check() instead. However page fault allows DAX and !anon_vma cases, so added a new flag, in_pf, to hugepage_vma_check() to make page fault work correctly. The in_pf flag is also used to skip shmem and file THP for page fault since shmem handles THP in its own shmem_fault() and file THP allocation on fault is not supported yet. Also remove hugepage_vma_enabled() since hugepage_vma_check() is the only caller now, it is not necessary to have a helper function. Link: https://lkml.kernel.org/r/20220616174840.1202070-6-shy828301@gmail.com Signed-off-by: Yang Shi <shy828301@gmail.com> Reviewed-by: Zach O'Keefe <zokeefe@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Alex Sierra
|
3218f8712d |
mm: handling Non-LRU pages returned by vm_normal_pages
With DEVICE_COHERENT, we'll soon have vm_normal_pages() return device-managed anonymous pages that are not LRU pages. Although they behave like normal pages for purposes of mapping in CPU page, and for COW. They do not support LRU lists, NUMA migration or THP. Callers to follow_page() currently don't expect ZONE_DEVICE pages, however, with DEVICE_COHERENT we might now return ZONE_DEVICE. Check for ZONE_DEVICE pages in applicable users of follow_page() as well. Link: https://lkml.kernel.org/r/20220715150521.18165-5-alex.sierra@amd.com Signed-off-by: Alex Sierra <alex.sierra@amd.com> Acked-by: Felix Kuehling <Felix.Kuehling@amd.com> [v2] Reviewed-by: Alistair Popple <apopple@nvidia.com> [v6] Cc: Christoph Hellwig <hch@lst.de> Cc: David Hildenbrand <david@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ralph Campbell <rcampbell@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Gowans, James
|
14c99d6594 |
mm: split huge PUD on wp_huge_pud fallback
Currently the implementation will split the PUD when a fallback is taken
inside the create_huge_pud function. This isn't where it should be done:
the splitting should be done in wp_huge_pud, just like it's done for PMDs.
Reason being that if a callback is taken during create, there is no PUD
yet so nothing to split, whereas if a fallback is taken when encountering
a write protection fault there is something to split.
It looks like this was the original intention with the commit where the
splitting was introduced, but somehow it got moved to the wrong place
between v1 and v2 of the patch series. Rebase mistake perhaps.
Link: https://lkml.kernel.org/r/6f48d622eb8bce1ae5dd75327b0b73894a2ec407.camel@amazon.com
Fixes:
|
||
|
Peter Xu
|
d92725256b |
mm: avoid unnecessary page fault retires on shared memory types
I observed that for each of the shared file-backed page faults, we're very likely to retry one more time for the 1st write fault upon no page. It's because we'll need to release the mmap lock for dirty rate limit purpose with balance_dirty_pages_ratelimited() (in fault_dirty_shared_page()). Then after that throttling we return VM_FAULT_RETRY. We did that probably because VM_FAULT_RETRY is the only way we can return to the fault handler at that time telling it we've released the mmap lock. However that's not ideal because it's very likely the fault does not need to be retried at all since the pgtable was well installed before the throttling, so the next continuous fault (including taking mmap read lock, walk the pgtable, etc.) could be in most cases unnecessary. It's not only slowing down page faults for shared file-backed, but also add more mmap lock contention which is in most cases not needed at all. To observe this, one could try to write to some shmem page and look at "pgfault" value in /proc/vmstat, then we should expect 2 counts for each shmem write simply because we retried, and vm event "pgfault" will capture that. To make it more efficient, add a new VM_FAULT_COMPLETED return code just to show that we've completed the whole fault and released the lock. It's also a hint that we should very possibly not need another fault immediately on this page because we've just completed it. This patch provides a ~12% perf boost on my aarch64 test VM with a simple program sequentially dirtying 400MB shmem file being mmap()ed and these are the time it needs: Before: 650.980 ms (+-1.94%) After: 569.396 ms (+-1.38%) I believe it could help more than that. We need some special care on GUP and the s390 pgfault handler (for gmap code before returning from pgfault), the rest changes in the page fault handlers should be relatively straightforward. Another thing to mention is that mm_account_fault() does take this new fault as a generic fault to be accounted, unlike VM_FAULT_RETRY. I explicitly didn't touch hmm_vma_fault() and break_ksm() because they do not handle VM_FAULT_RETRY even with existing code, so I'm literally keeping them as-is. Link: https://lkml.kernel.org/r/20220530183450.42886-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vineet Gupta <vgupta@kernel.org> Acked-by: Guo Ren <guoren@kernel.org> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm part] Acked-by: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Stafford Horne <shorne@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Johannes Berg <johannes@sipsolutions.net> Cc: Brian Cain <bcain@quicinc.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Richard Weinberger <richard@nod.at> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Janosch Frank <frankja@linux.ibm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Jonas Bonn <jonas@southpole.se> Cc: Will Deacon <will@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Michal Simek <monstr@monstr.eu> Cc: Matt Turner <mattst88@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: David Hildenbrand <david@redhat.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Chris Zankel <chris@zankel.net> Cc: Hugh Dickins <hughd@google.com> Cc: Dinh Nguyen <dinguyen@kernel.org> Cc: Rich Felker <dalias@libc.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Helge Deller <deller@gmx.de> Cc: Yoshinori Sato <ysato@users.osdn.me> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Yang Yang
|
662ce1dc9c |
delayacct: track delays from write-protect copy
Delay accounting does not track the delay of write-protect copy. When
tasks trigger many write-protect copys(include COW and unsharing of
anonymous pages[1]), it may spend a amount of time waiting for them. To
get the delay of tasks in write-protect copy, could help users to evaluate
the impact of using KSM or fork() or GUP.
Also update tools/accounting/getdelays.c:
/ # ./getdelays -dl -p 231
print delayacct stats ON
listen forever
PID 231
CPU count real total virtual total delay total delay average
6247 1859000000 2154070021 1674255063 0.268ms
IO count delay total delay average
0 0 0ms
SWAP count delay total delay average
0 0 0ms
RECLAIM count delay total delay average
0 0 0ms
THRASHING count delay total delay average
0 0 0ms
COMPACT count delay total delay average
3 72758 0ms
WPCOPY count delay total delay average
3635 271567604 0ms
[1] commit 31cc5bc4af70("mm: support GUP-triggered unsharing of anonymous pages")
Link: https://lkml.kernel.org/r/20220409014342.2505532-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jiang Xuexin <jiang.xuexin@zte.com.cn>
Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn>
Reviewed-by: wangyong <wang.yong12@zte.com.cn>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Linus Torvalds
|
8291eaafed |
Two followon fixes for the post-5.19 series "Use pageblock_order for cma
and alloc_contig_range alignment", from Zi Yan.
A series of z3fold cleanups and fixes from Miaohe Lin.
Some memcg selftests work from Michal Koutný <mkoutny@suse.com>
Some swap fixes and cleanups from Miaohe Lin.
Several individual minor fixups.
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Merge tag 'mm-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull more MM updates from Andrew Morton:
- Two follow-on fixes for the post-5.19 series "Use pageblock_order for
cma and alloc_contig_range alignment", from Zi Yan.
- A series of z3fold cleanups and fixes from Miaohe Lin.
- Some memcg selftests work from Michal Koutný <mkoutny@suse.com>
- Some swap fixes and cleanups from Miaohe Lin
- Several individual minor fixups
* tag 'mm-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (25 commits)
mm/shmem.c: suppress shift warning
mm: Kconfig: reorganize misplaced mm options
mm: kasan: fix input of vmalloc_to_page()
mm: fix is_pinnable_page against a cma page
mm: filter out swapin error entry in shmem mapping
mm/shmem: fix infinite loop when swap in shmem error at swapoff time
mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range
mm/swapfile: fix lost swap bits in unuse_pte()
mm/swapfile: unuse_pte can map random data if swap read fails
selftests: memcg: factor out common parts of memory.{low,min} tests
selftests: memcg: remove protection from top level memcg
selftests: memcg: adjust expected reclaim values of protected cgroups
selftests: memcg: expect no low events in unprotected sibling
selftests: memcg: fix compilation
mm/z3fold: fix z3fold_page_migrate races with z3fold_map
mm/z3fold: fix z3fold_reclaim_page races with z3fold_free
mm/z3fold: always clear PAGE_CLAIMED under z3fold page lock
mm/z3fold: put z3fold page back into unbuddied list when reclaim or migration fails
revert "mm/z3fold.c: allow __GFP_HIGHMEM in z3fold_alloc"
mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc
...
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||
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Miaohe Lin
|
9f186f9e5f |
mm/swapfile: unuse_pte can map random data if swap read fails
Patch series "A few fixup patches for mm", v4. This series contains a few patches to avoid mapping random data if swap read fails and fix lost swap bits in unuse_pte. Also we free hwpoison and swapin error entry in madvise_free_pte_range and so on. More details can be found in the respective changelogs. This patch (of 5): There is a bug in unuse_pte(): when swap page happens to be unreadable, page filled with random data is mapped into user address space. In case of error, a special swap entry indicating swap read fails is set to the page table. So the swapcache page can be freed and the user won't end up with a permanently mounted swap because a sector is bad. And if the page is accessed later, the user process will be killed so that corrupted data is never consumed. On the other hand, if the page is never accessed, the user won't even notice it. Link: https://lkml.kernel.org/r/20220519125030.21486-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220519125030.21486-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: David Howells <dhowells@redhat.com> Cc: NeilBrown <neilb@suse.de> Cc: Alistair Popple <apopple@nvidia.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: Ralph Campbell <rcampbell@nvidia.com> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Linus Torvalds
|
98931dd95f |
Yang Shi has improved the behaviour of khugepaged collapsing of readonly
file-backed transparent hugepages.
Johannes Weiner has arranged for zswap memory use to be tracked and
managed on a per-cgroup basis.
Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for runtime
enablement of the recent huge page vmemmap optimization feature.
Baolin Wang contributes a series to fix some issues around hugetlb
pagetable invalidation.
Zhenwei Pi has fixed some interactions between hwpoisoned pages and
virtualization.
Tong Tiangen has enabled the use of the presently x86-only
page_table_check debugging feature on arm64 and riscv.
David Vernet has done some fixup work on the memcg selftests.
Peter Xu has taught userfaultfd to handle write protection faults against
shmem- and hugetlbfs-backed files.
More DAMON development from SeongJae Park - adding online tuning of the
feature and support for monitoring of fixed virtual address ranges. Also
easier discovery of which monitoring operations are available.
Nadav Amit has done some optimization of TLB flushing during mprotect().
Neil Brown continues to labor away at improving our swap-over-NFS support.
David Hildenbrand has some fixes to anon page COWing versus
get_user_pages().
Peng Liu fixed some errors in the core hugetlb code.
Joao Martins has reduced the amount of memory consumed by device-dax's
compound devmaps.
Some cleanups of the arch-specific pagemap code from Anshuman Khandual.
Muchun Song has found and fixed some errors in the TLB flushing of
transparent hugepages.
Roman Gushchin has done more work on the memcg selftests.
And, of course, many smaller fixes and cleanups. Notably, the customary
million cleanup serieses from Miaohe Lin.
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Merge tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
"Almost all of MM here. A few things are still getting finished off,
reviewed, etc.
- Yang Shi has improved the behaviour of khugepaged collapsing of
readonly file-backed transparent hugepages.
- Johannes Weiner has arranged for zswap memory use to be tracked and
managed on a per-cgroup basis.
- Munchun Song adds a /proc knob ("hugetlb_optimize_vmemmap") for
runtime enablement of the recent huge page vmemmap optimization
feature.
- Baolin Wang contributes a series to fix some issues around hugetlb
pagetable invalidation.
- Zhenwei Pi has fixed some interactions between hwpoisoned pages and
virtualization.
- Tong Tiangen has enabled the use of the presently x86-only
page_table_check debugging feature on arm64 and riscv.
- David Vernet has done some fixup work on the memcg selftests.
- Peter Xu has taught userfaultfd to handle write protection faults
against shmem- and hugetlbfs-backed files.
- More DAMON development from SeongJae Park - adding online tuning of
the feature and support for monitoring of fixed virtual address
ranges. Also easier discovery of which monitoring operations are
available.
- Nadav Amit has done some optimization of TLB flushing during
mprotect().
- Neil Brown continues to labor away at improving our swap-over-NFS
support.
- David Hildenbrand has some fixes to anon page COWing versus
get_user_pages().
- Peng Liu fixed some errors in the core hugetlb code.
- Joao Martins has reduced the amount of memory consumed by
device-dax's compound devmaps.
- Some cleanups of the arch-specific pagemap code from Anshuman
Khandual.
- Muchun Song has found and fixed some errors in the TLB flushing of
transparent hugepages.
- Roman Gushchin has done more work on the memcg selftests.
... and, of course, many smaller fixes and cleanups. Notably, the
customary million cleanup serieses from Miaohe Lin"
* tag 'mm-stable-2022-05-25' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (381 commits)
mm: kfence: use PAGE_ALIGNED helper
selftests: vm: add the "settings" file with timeout variable
selftests: vm: add "test_hmm.sh" to TEST_FILES
selftests: vm: check numa_available() before operating "merge_across_nodes" in ksm_tests
selftests: vm: add migration to the .gitignore
selftests/vm/pkeys: fix typo in comment
ksm: fix typo in comment
selftests: vm: add process_mrelease tests
Revert "mm/vmscan: never demote for memcg reclaim"
mm/kfence: print disabling or re-enabling message
include/trace/events/percpu.h: cleanup for "percpu: improve percpu_alloc_percpu event trace"
include/trace/events/mmflags.h: cleanup for "tracing: incorrect gfp_t conversion"
mm: fix a potential infinite loop in start_isolate_page_range()
MAINTAINERS: add Muchun as co-maintainer for HugeTLB
zram: fix Kconfig dependency warning
mm/shmem: fix shmem folio swapoff hang
cgroup: fix an error handling path in alloc_pagecache_max_30M()
mm: damon: use HPAGE_PMD_SIZE
tracing: incorrect isolate_mote_t cast in mm_vmscan_lru_isolate
nodemask.h: fix compilation error with GCC12
...
|
||
|
Miaohe Lin
|
eacde32757 |
mm/swap: avoid calling swp_swap_info when try to check SWP_STABLE_WRITES
Use flags of si directly to check SWP_STABLE_WRITES to avoid possible READ_ONCE and thus save some cpu cycles. [akpm@linux-foundation.org: use data_race() on si->flags, per Neil] Link: https://lkml.kernel.org/r/20220509131416.17553-10-linmiaohe@huawei.com Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: NeilBrown <neilb@suse.de> Cc: Peter Xu <peterx@redhat.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Oscar Salvador <osalvador@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Wan Jiabing
|
54943a1a4d |
mm/shmem: remove duplicate include in memory.c
Fix following checkincludes.pl warning: mm/memory.c: linux/mm_inline.h is included more than once. The include is in line 44. Remove the duplicated here. Link: https://lkml.kernel.org/r/20220427064717.803019-1-wanjiabing@vivo.com Signed-off-by: Wan Jiabing <wanjiabing@vivo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
bc70fbf269 |
mm/hugetlb: handle uffd-wp during fork()
Firstly, we'll need to pass in dst_vma into copy_hugetlb_page_range() because for uffd-wp it's the dst vma that matters on deciding how we should treat uffd-wp protected ptes. We should recognize pte markers during fork and do the pte copy if needed. [lkp@intel.com: vma_needs_copy can be static] Link: https://lkml.kernel.org/r/Ylb0CGeFJlc4EzLk@7ec4ff11d4ae Link: https://lkml.kernel.org/r/20220405014918.14932-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
05e90bd05e |
mm/hugetlb: only drop uffd-wp special pte if required
As with shmem uffd-wp special ptes, only drop the uffd-wp special swap pte if unmapping an entire vma or synchronized such that faults can not race with the unmap operation. This requires passing zap_flags all the way to the lowest level hugetlb unmap routine: __unmap_hugepage_range. In general, unmap calls originated in hugetlbfs code will pass the ZAP_FLAG_DROP_MARKER flag as synchronization is in place to prevent faults. The exception is hole punch which will first unmap without any synchronization. Later when hole punch actually removes the page from the file, it will check to see if there was a subsequent fault and if so take the hugetlb fault mutex while unmapping again. This second unmap will pass in ZAP_FLAG_DROP_MARKER. The justification of "whether to apply ZAP_FLAG_DROP_MARKER flag when unmap a hugetlb range" is (IMHO): we should never reach a state when a page fault could errornously fault in a page-cache page that was wr-protected to be writable, even in an extremely short period. That could happen if e.g. we pass ZAP_FLAG_DROP_MARKER when hugetlbfs_punch_hole() calls hugetlb_vmdelete_list(), because if a page faults after that call and before remove_inode_hugepages() is executed, the page cache can be mapped writable again in the small racy window, that can cause unexpected data overwritten. [peterx@redhat.com: fix sparse warning] Link: https://lkml.kernel.org/r/Ylcdw8I1L5iAoWhb@xz-m1.local [akpm@linux-foundation.org: move zap_flags_t from mm.h to mm_types.h to fix build issues] Link: https://lkml.kernel.org/r/20220405014915.14873-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
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Peter Xu
|
c56d1b62cc |
mm/shmem: handle uffd-wp during fork()
Normally we skip copy page when fork() for VM_SHARED shmem, but we can't skip it anymore if uffd-wp is enabled on dst vma. This should only happen when the src uffd has UFFD_FEATURE_EVENT_FORK enabled on uffd-wp shmem vma, so that VM_UFFD_WP will be propagated onto dst vma too, then we should copy the pgtables with uffd-wp bit and pte markers, because these information will be lost otherwise. Since the condition checks will become even more complicated for deciding "whether a vma needs to copy the pgtable during fork()", introduce a helper vma_needs_copy() for it, so everything will be clearer. Link: https://lkml.kernel.org/r/20220405014855.14468-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
999dad824c |
mm/shmem: persist uffd-wp bit across zapping for file-backed
File-backed memory is prone to being unmapped at any time. It means all information in the pte will be dropped, including the uffd-wp flag. To persist the uffd-wp flag, we'll use the pte markers. This patch teaches the zap code to understand uffd-wp and know when to keep or drop the uffd-wp bit. Add a new flag ZAP_FLAG_DROP_MARKER and set it in zap_details when we don't want to persist such an information, for example, when destroying the whole vma, or punching a hole in a shmem file. For the rest cases we should never drop the uffd-wp bit, or the wr-protect information will get lost. The new ZAP_FLAG_DROP_MARKER needs to be put into mm.h rather than memory.c because it'll be further referenced in hugetlb files later. Link: https://lkml.kernel.org/r/20220405014847.14295-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
9c28a205c0 |
mm/shmem: handle uffd-wp special pte in page fault handler
File-backed memories are prone to unmap/swap so the ptes are always
unstable, because they can be easily faulted back later using the page
cache. This could lead to uffd-wp getting lost when unmapping or swapping
out such memory. One example is shmem. PTE markers are needed to store
those information.
This patch prepares it by handling uffd-wp pte markers first it is applied
elsewhere, so that the page fault handler can recognize uffd-wp pte
markers.
The handling of uffd-wp pte markers is similar to missing fault, it's just
that we'll handle this "missing fault" when we see the pte markers,
meanwhile we need to make sure the marker information is kept during
processing the fault.
This is a slow path of uffd-wp handling, because zapping of wr-protected
shmem ptes should be rare. So far it should only trigger in two
conditions:
(1) When trying to punch holes in shmem_fallocate(), there is an
optimization to zap the pgtables before evicting the page.
(2) When swapping out shmem pages.
Because of this, the page fault handling is simplifed too by not sending
the wr-protect message in the 1st page fault, instead the page will be
installed read-only, so the uffd-wp message will be generated in the next
fault, which will trigger the do_wp_page() path of general uffd-wp
handling.
Disable fault-around for all uffd-wp registered ranges for extra safety
just like uffd-minor fault, and clean the code up.
Link: https://lkml.kernel.org/r/20220405014844.14239-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Peter Xu
|
f46f2adecd |
mm: check against orig_pte for finish_fault()
This patch allows do_fault() to trigger on !pte_none() cases too. This prepares for the pte markers to be handled by do_fault() just like none pte. To achieve this, instead of unconditionally check against pte_none() in finish_fault(), we may hit the case that the orig_pte was some pte marker so what we want to do is to replace the pte marker with some valid pte entry. Then if orig_pte was set we'd want to check the current *pte (under pgtable lock) against orig_pte rather than none pte. Right now there's no solid way to safely reference orig_pte because when pmd is not allocated handle_pte_fault() will not initialize orig_pte, so it's not safe to reference it. There's another solution proposed before this patch to do pte_clear() for vmf->orig_pte for pmd==NULL case, however it turns out it'll break arm32 because arm32 could have assumption that pte_t* pointer will always reside on a real ram32 pgtable, not any kernel stack variable. To solve this, we add a new flag FAULT_FLAG_ORIG_PTE_VALID, and it'll be set along with orig_pte when there is valid orig_pte, or it'll be cleared when orig_pte was not initialized. It'll be updated every time we call handle_pte_fault(), so e.g. if a page fault retry happened it'll be properly updated along with orig_pte. [1] https://lore.kernel.org/lkml/710c48c9-406d-e4c5-a394-10501b951316@samsung.com/ [akpm@linux-foundation.org: coding-style cleanups] [peterx@redhat.com: fix crash reported by Marek] Link: https://lkml.kernel.org/r/Ylb9rXJyPm8/ao8f@xz-m1.local Link: https://lkml.kernel.org/r/20220405014836.14077-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Peter Xu
|
5c041f5d1f |
mm: teach core mm about pte markers
This patch still does not use pte marker in any way, however it teaches the core mm about the pte marker idea. For example, handle_pte_marker() is introduced that will parse and handle all the pte marker faults. Many of the places are more about commenting it up - so that we know there's the possibility of pte marker showing up, and why we don't need special code for the cases. [peterx@redhat.com: userfaultfd.c needs swapops.h] Link: https://lkml.kernel.org/r/YmRlVj3cdizYJsr0@xz-m1.local Link: https://lkml.kernel.org/r/20220405014833.14015-1-peterx@redhat.com Signed-off-by: Peter Xu <peterx@redhat.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Cc: David Hildenbrand <david@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Kirill A . Shutemov" <kirill@shutemov.name> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
NeilBrown
|
5169b844b7 |
mm: submit multipage reads for SWP_FS_OPS swap-space
swap_readpage() is given one page at a time, but may be called repeatedly in succession. For block-device swap-space, the blk_plug functionality allows the multiple pages to be combined together at lower layers. That cannot be used for SWP_FS_OPS as blk_plug may not exist - it is only active when CONFIG_BLOCK=y. Consequently all swap reads over NFS are single page reads. With this patch we pass in a pointer-to-pointer when swap_readpage can store state between calls - much like the effect of blk_plug. After calling swap_readpage() some number of times, the state will be passed to swap_read_unplug() which can submit the combined request. Link: https://lkml.kernel.org/r/164859778127.29473.14059420492644907783.stgit@noble.brown Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
NeilBrown
|
014bb1de4f |
mm: create new mm/swap.h header file
Patch series "MM changes to improve swap-over-NFS support". Assorted improvements for swap-via-filesystem. This is a resend of these patches, rebased on current HEAD. The only substantial changes is that swap_dirty_folio has replaced swap_set_page_dirty. Currently swap-via-fs (SWP_FS_OPS) doesn't work for any filesystem. It has previously worked for NFS but that broke a few releases back. This series changes to use a new ->swap_rw rather than ->readpage and ->direct_IO. It also makes other improvements. There is a companion series already in linux-next which fixes various issues with NFS. Once both series land, a final patch is needed which changes NFS over to use ->swap_rw. This patch (of 10): Many functions declared in include/linux/swap.h are only used within mm/ Create a new "mm/swap.h" and move some of these declarations there. Remove the redundant 'extern' from the function declarations. [akpm@linux-foundation.org: mm/memory-failure.c needs mm/swap.h] Link: https://lkml.kernel.org/r/164859751830.29473.5309689752169286816.stgit@noble.brown Link: https://lkml.kernel.org/r/164859778120.29473.11725907882296224053.stgit@noble.brown Signed-off-by: NeilBrown <neilb@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: David Howells <dhowells@redhat.com> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Cc: Trond Myklebust <trond.myklebust@hammerspace.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Miaohe Lin <linmiaohe@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
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David Hildenbrand
|
1493a1913e |
mm/swap: remember PG_anon_exclusive via a swp pte bit
Patch series "mm: COW fixes part 3: reliable GUP R/W FOLL_GET of anonymous pages", v2.
This series fixes memory corruptions when a GUP R/W reference (FOLL_WRITE
| FOLL_GET) was taken on an anonymous page and COW logic fails to detect
exclusivity of the page to then replacing the anonymous page by a copy in
the page table: The GUP reference lost synchronicity with the pages mapped
into the page tables. This series focuses on x86, arm64, s390x and
ppc64/book3s -- other architectures are fairly easy to support by
implementing __HAVE_ARCH_PTE_SWP_EXCLUSIVE.
This primarily fixes the O_DIRECT memory corruptions that can happen on
concurrent swapout, whereby we lose DMA reads to a page (modifying the
user page by writing to it).
O_DIRECT currently uses FOLL_GET for short-term (!FOLL_LONGTERM) DMA
from/to a user page. In the long run, we want to convert it to properly
use FOLL_PIN, and John is working on it, but that might take a while and
might not be easy to backport. In the meantime, let's restore what used
to work before we started modifying our COW logic: make R/W FOLL_GET
references reliable as long as there is no fork() after GUP involved.
This is just the natural follow-up of part 2, that will also further
reduce "wrong COW" on the swapin path, for example, when we cannot remove
a page from the swapcache due to concurrent writeback, or if we have two
threads faulting on the same swapped-out page. Fixing O_DIRECT is just a
nice side-product
This issue, including other related COW issues, has been summarized in [3]
under 2):
"
2. Intra Process Memory Corruptions due to Wrong COW (FOLL_GET)
It was discovered that we can create a memory corruption by reading a
file via O_DIRECT to a part (e.g., first 512 bytes) of a page,
concurrently writing to an unrelated part (e.g., last byte) of the same
page, and concurrently write-protecting the page via clear_refs
SOFTDIRTY tracking [6].
For the reproducer, the issue is that O_DIRECT grabs a reference of the
target page (via FOLL_GET) and clear_refs write-protects the relevant
page table entry. On successive write access to the page from the
process itself, we wrongly COW the page when resolving the write fault,
resulting in a loss of synchronicity and consequently a memory corruption.
While some people might think that using clear_refs in this combination
is a corner cases, it turns out to be a more generic problem unfortunately.
For example, it was just recently discovered that we can similarly
create a memory corruption without clear_refs, simply by concurrently
swapping out the buffer pages [7]. Note that we nowadays even use the
swap infrastructure in Linux without an actual swap disk/partition: the
prime example is zram which is enabled as default under Fedora [10].
The root issue is that a write-fault on a page that has additional
references results in a COW and thereby a loss of synchronicity
and consequently a memory corruption if two parties believe they are
referencing the same page.
"
We don't particularly care about R/O FOLL_GET references: they were never
reliable and O_DIRECT doesn't expect to observe modifications from a page
after DMA was started.
Note that:
* this only fixes the issue on x86, arm64, s390x and ppc64/book3s
("enterprise architectures"). Other architectures have to implement
__HAVE_ARCH_PTE_SWP_EXCLUSIVE to achieve the same.
* this does *not * consider any kind of fork() after taking the reference:
fork() after GUP never worked reliably with FOLL_GET.
* Not losing PG_anon_exclusive during swapout was the last remaining
piece. KSM already makes sure that there are no other references on
a page before considering it for sharing. Page migration maintains
PG_anon_exclusive and simply fails when there are additional references
(freezing the refcount fails). Only swapout code dropped the
PG_anon_exclusive flag because it requires more work to remember +
restore it.
With this series in place, most COW issues of [3] are fixed on said
architectures. Other architectures can implement
__HAVE_ARCH_PTE_SWP_EXCLUSIVE fairly easily.
[1] https://lkml.kernel.org/r/20220329160440.193848-1-david@redhat.com
[2] https://lkml.kernel.org/r/20211217113049.23850-1-david@redhat.com
[3] https://lore.kernel.org/r/3ae33b08-d9ef-f846-56fb-645e3b9b4c66@redhat.com
This patch (of 8):
Currently, we clear PG_anon_exclusive in try_to_unmap() and forget about
it. We do this, to keep fork() logic on swap entries easy and efficient:
for example, if we wouldn't clear it when unmapping, we'd have to lookup
the page in the swapcache for each and every swap entry during fork() and
clear PG_anon_exclusive if set.
Instead, we want to store that information directly in the swap pte,
protected by the page table lock, similarly to how we handle
SWP_MIGRATION_READ_EXCLUSIVE for migration entries. However, for actual
swap entries, we don't want to mess with the swap type (e.g., still one
bit) because it overcomplicates swap code.
In try_to_unmap(), we already reject to unmap in case the page might be
pinned, because we must not lose PG_anon_exclusive on pinned pages ever.
Checking if there are other unexpected references reliably *before*
completely unmapping a page is unfortunately not really possible: THP
heavily overcomplicate the situation. Once fully unmapped it's easier --
we, for example, make sure that there are no unexpected references *after*
unmapping a page before starting writeback on that page.
So, we currently might end up unmapping a page and clearing
PG_anon_exclusive if that page has additional references, for example, due
to a FOLL_GET.
do_swap_page() has to re-determine if a page is exclusive, which will
easily fail if there are other references on a page, most prominently GUP
references via FOLL_GET. This can currently result in memory corruptions
when taking a FOLL_GET | FOLL_WRITE reference on a page even when fork()
is never involved: try_to_unmap() will succeed, and when refaulting the
page, it cannot be marked exclusive and will get replaced by a copy in the
page tables on the next write access, resulting in writes via the GUP
reference to the page being lost.
In an ideal world, everybody that uses GUP and wants to modify page
content, such as O_DIRECT, would properly use FOLL_PIN. However, that
conversion will take a while. It's easier to fix what used to work in the
past (FOLL_GET | FOLL_WRITE) remembering PG_anon_exclusive. In addition,
by remembering PG_anon_exclusive we can further reduce unnecessary COW in
some cases, so it's the natural thing to do.
So let's transfer the PG_anon_exclusive information to the swap pte and
store it via an architecture-dependant pte bit; use that information when
restoring the swap pte in do_swap_page() and unuse_pte(). During fork(),
we simply have to clear the pte bit and are done.
Of course, there is one corner case to handle: swap backends that don't
support concurrent page modifications while the page is under writeback.
Special case these, and drop the exclusive marker. Add a comment why that
is just fine (also, reuse_swap_page() would have done the same in the
past).
In the future, we'll hopefully have all architectures support
__HAVE_ARCH_PTE_SWP_EXCLUSIVE, such that we can get rid of the empty stubs
and the define completely. Then, we can also convert
SWP_MIGRATION_READ_EXCLUSIVE. For architectures it's fairly easy to
support: either simply use a yet unused pte bit that can be used for swap
entries, steal one from the arch type bits if they exceed 5, or steal one
from the offset bits.
Note: R/O FOLL_GET references were never really reliable, especially when
taking one on a shared page and then writing to the page (e.g., GUP after
fork()). FOLL_GET, including R/W references, were never really reliable
once fork was involved (e.g., GUP before fork(), GUP during fork()). KSM
steps back in case it stumbles over unexpected references and is,
therefore, fine.
[david@redhat.com: fix SWP_STABLE_WRITES test]
Link: https://lkml.kernel.org/r/ac725bcb-313a-4fff-250a-68ba9a8f85fb@redhat.comLink: https://lkml.kernel.org/r/20220329164329.208407-1-david@redhat.com
Link: https://lkml.kernel.org/r/20220329164329.208407-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jann Horn <jannh@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Nadav Amit <namit@vmware.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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David Hildenbrand
|
c89357e27f |
mm: support GUP-triggered unsharing of anonymous pages
Whenever GUP currently ends up taking a R/O pin on an anonymous page that
might be shared -- mapped R/O and !PageAnonExclusive() -- any write fault
on the page table entry will end up replacing the mapped anonymous page
due to COW, resulting in the GUP pin no longer being consistent with the
page actually mapped into the page table.
The possible ways to deal with this situation are:
(1) Ignore and pin -- what we do right now.
(2) Fail to pin -- which would be rather surprising to callers and
could break user space.
(3) Trigger unsharing and pin the now exclusive page -- reliable R/O
pins.
We want to implement 3) because it provides the clearest semantics and
allows for checking in unpin_user_pages() and friends for possible BUGs:
when trying to unpin a page that's no longer exclusive, clearly something
went very wrong and might result in memory corruptions that might be hard
to debug. So we better have a nice way to spot such issues.
To implement 3), we need a way for GUP to trigger unsharing:
FAULT_FLAG_UNSHARE. FAULT_FLAG_UNSHARE is only applicable to R/O mapped
anonymous pages and resembles COW logic during a write fault. However, in
contrast to a write fault, GUP-triggered unsharing will, for example,
still maintain the write protection.
Let's implement FAULT_FLAG_UNSHARE by hooking into the existing write
fault handlers for all applicable anonymous page types: ordinary pages,
THP and hugetlb.
* If FAULT_FLAG_UNSHARE finds a R/O-mapped anonymous page that has been
marked exclusive in the meantime by someone else, there is nothing to do.
* If FAULT_FLAG_UNSHARE finds a R/O-mapped anonymous page that's not
marked exclusive, it will try detecting if the process is the exclusive
owner. If exclusive, it can be set exclusive similar to reuse logic
during write faults via page_move_anon_rmap() and there is nothing
else to do; otherwise, we either have to copy and map a fresh,
anonymous exclusive page R/O (ordinary pages, hugetlb), or split the
THP.
This commit is heavily based on patches by Andrea.
Link: https://lkml.kernel.org/r/20220428083441.37290-16-david@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Co-developed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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David Hildenbrand
|
6c287605fd |
mm: remember exclusively mapped anonymous pages with PG_anon_exclusive
Let's mark exclusively mapped anonymous pages with PG_anon_exclusive as
exclusive, and use that information to make GUP pins reliable and stay
consistent with the page mapped into the page table even if the page table
entry gets write-protected.
With that information at hand, we can extend our COW logic to always reuse
anonymous pages that are exclusive. For anonymous pages that might be
shared, the existing logic applies.
As already documented, PG_anon_exclusive is usually only expressive in
combination with a page table entry. Especially PTE vs. PMD-mapped
anonymous pages require more thought, some examples: due to mremap() we
can easily have a single compound page PTE-mapped into multiple page
tables exclusively in a single process -- multiple page table locks apply.
Further, due to MADV_WIPEONFORK we might not necessarily write-protect
all PTEs, and only some subpages might be pinned. Long story short: once
PTE-mapped, we have to track information about exclusivity per sub-page,
but until then, we can just track it for the compound page in the head
page and not having to update a whole bunch of subpages all of the time
for a simple PMD mapping of a THP.
For simplicity, this commit mostly talks about "anonymous pages", while
it's for THP actually "the part of an anonymous folio referenced via a
page table entry".
To not spill PG_anon_exclusive code all over the mm code-base, we let the
anon rmap code to handle all PG_anon_exclusive logic it can easily handle.
If a writable, present page table entry points at an anonymous (sub)page,
that (sub)page must be PG_anon_exclusive. If GUP wants to take a reliably
pin (FOLL_PIN) on an anonymous page references via a present page table
entry, it must only pin if PG_anon_exclusive is set for the mapped
(sub)page.
This commit doesn't adjust GUP, so this is only implicitly handled for
FOLL_WRITE, follow-up commits will teach GUP to also respect it for
FOLL_PIN without FOLL_WRITE, to make all GUP pins of anonymous pages fully
reliable.
Whenever an anonymous page is to be shared (fork(), KSM), or when
temporarily unmapping an anonymous page (swap, migration), the relevant
PG_anon_exclusive bit has to be cleared to mark the anonymous page
possibly shared. Clearing will fail if there are GUP pins on the page:
* For fork(), this means having to copy the page and not being able to
share it. fork() protects against concurrent GUP using the PT lock and
the src_mm->write_protect_seq.
* For KSM, this means sharing will fail. For swap this means, unmapping
will fail, For migration this means, migration will fail early. All
three cases protect against concurrent GUP using the PT lock and a
proper clear/invalidate+flush of the relevant page table entry.
This fixes memory corruptions reported for FOLL_PIN | FOLL_WRITE, when a
pinned page gets mapped R/O and the successive write fault ends up
replacing the page instead of reusing it. It improves the situation for
O_DIRECT/vmsplice/... that still use FOLL_GET instead of FOLL_PIN, if
fork() is *not* involved, however swapout and fork() are still
problematic. Properly using FOLL_PIN instead of FOLL_GET for these GUP
users will fix the issue for them.
I. Details about basic handling
I.1. Fresh anonymous pages
page_add_new_anon_rmap() and hugepage_add_new_anon_rmap() will mark the
given page exclusive via __page_set_anon_rmap(exclusive=1). As that is
the mechanism fresh anonymous pages come into life (besides migration code
where we copy the page->mapping), all fresh anonymous pages will start out
as exclusive.
I.2. COW reuse handling of anonymous pages
When a COW handler stumbles over a (sub)page that's marked exclusive, it
simply reuses it. Otherwise, the handler tries harder under page lock to
detect if the (sub)page is exclusive and can be reused. If exclusive,
page_move_anon_rmap() will mark the given (sub)page exclusive.
Note that hugetlb code does not yet check for PageAnonExclusive(), as it
still uses the old COW logic that is prone to the COW security issue
because hugetlb code cannot really tolerate unnecessary/wrong COW as huge
pages are a scarce resource.
I.3. Migration handling
try_to_migrate() has to try marking an exclusive anonymous page shared via
page_try_share_anon_rmap(). If it fails because there are GUP pins on the
page, unmap fails. migrate_vma_collect_pmd() and
__split_huge_pmd_locked() are handled similarly.
Writable migration entries implicitly point at shared anonymous pages.
For readable migration entries that information is stored via a new
"readable-exclusive" migration entry, specific to anonymous pages.
When restoring a migration entry in remove_migration_pte(), information
about exlusivity is detected via the migration entry type, and
RMAP_EXCLUSIVE is set accordingly for
page_add_anon_rmap()/hugepage_add_anon_rmap() to restore that information.
I.4. Swapout handling
try_to_unmap() has to try marking the mapped page possibly shared via
page_try_share_anon_rmap(). If it fails because there are GUP pins on the
page, unmap fails. For now, information about exclusivity is lost. In
the future, we might want to remember that information in the swap entry
in some cases, however, it requires more thought, care, and a way to store
that information in swap entries.
I.5. Swapin handling
do_swap_page() will never stumble over exclusive anonymous pages in the
swap cache, as try_to_migrate() prohibits that. do_swap_page() always has
to detect manually if an anonymous page is exclusive and has to set
RMAP_EXCLUSIVE for page_add_anon_rmap() accordingly.
I.6. THP handling
__split_huge_pmd_locked() has to move the information about exclusivity
from the PMD to the PTEs.
a) In case we have a readable-exclusive PMD migration entry, simply
insert readable-exclusive PTE migration entries.
b) In case we have a present PMD entry and we don't want to freeze
("convert to migration entries"), simply forward PG_anon_exclusive to
all sub-pages, no need to temporarily clear the bit.
c) In case we have a present PMD entry and want to freeze, handle it
similar to try_to_migrate(): try marking the page shared first. In
case we fail, we ignore the "freeze" instruction and simply split
ordinarily. try_to_migrate() will properly fail because the THP is
still mapped via PTEs.
When splitting a compound anonymous folio (THP), the information about
exclusivity is implicitly handled via the migration entries: no need to
replicate PG_anon_exclusive manually.
I.7. fork() handling fork() handling is relatively easy, because
PG_anon_exclusive is only expressive for some page table entry types.
a) Present anonymous pages
page_try_dup_anon_rmap() will mark the given subpage shared -- which will
fail if the page is pinned. If it failed, we have to copy (or PTE-map a
PMD to handle it on the PTE level).
Note that device exclusive entries are just a pointer at a PageAnon()
page. fork() will first convert a device exclusive entry to a present
page table and handle it just like present anonymous pages.
b) Device private entry
Device private entries point at PageAnon() pages that cannot be mapped
directly and, therefore, cannot get pinned.
page_try_dup_anon_rmap() will mark the given subpage shared, which cannot
fail because they cannot get pinned.
c) HW poison entries
PG_anon_exclusive will remain untouched and is stale -- the page table
entry is just a placeholder after all.
d) Migration entries
Writable and readable-exclusive entries are converted to readable entries:
possibly shared.
I.8. mprotect() handling
mprotect() only has to properly handle the new readable-exclusive
migration entry:
When write-protecting a migration entry that points at an anonymous page,
remember the information about exclusivity via the "readable-exclusive"
migration entry type.
II. Migration and GUP-fast
Whenever replacing a present page table entry that maps an exclusive
anonymous page by a migration entry, we have to mark the page possibly
shared and synchronize against GUP-fast by a proper clear/invalidate+flush
to make the following scenario impossible:
1. try_to_migrate() places a migration entry after checking for GUP pins
and marks the page possibly shared.
2. GUP-fast pins the page due to lack of synchronization
3. fork() converts the "writable/readable-exclusive" migration entry into a
readable migration entry
4. Migration fails due to the GUP pin (failing to freeze the refcount)
5. Migration entries are restored. PG_anon_exclusive is lost
-> We have a pinned page that is not marked exclusive anymore.
Note that we move information about exclusivity from the page to the
migration entry as it otherwise highly overcomplicates fork() and
PTE-mapping a THP.
III. Swapout and GUP-fast
Whenever replacing a present page table entry that maps an exclusive
anonymous page by a swap entry, we have to mark the page possibly shared
and synchronize against GUP-fast by a proper clear/invalidate+flush to
make the following scenario impossible:
1. try_to_unmap() places a swap entry after checking for GUP pins and
clears exclusivity information on the page.
2. GUP-fast pins the page due to lack of synchronization.
-> We have a pinned page that is not marked exclusive anymore.
If we'd ever store information about exclusivity in the swap entry,
similar to migration handling, the same considerations as in II would
apply. This is future work.
Link: https://lkml.kernel.org/r/20220428083441.37290-13-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
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David Hildenbrand
|
78fbe906cc |
mm/page-flags: reuse PG_mappedtodisk as PG_anon_exclusive for PageAnon() pages
The basic question we would like to have a reliable and efficient answer
to is: is this anonymous page exclusive to a single process or might it be
shared? We need that information for ordinary/single pages, hugetlb
pages, and possibly each subpage of a THP.
Introduce a way to mark an anonymous page as exclusive, with the ultimate
goal of teaching our COW logic to not do "wrong COWs", whereby GUP pins
lose consistency with the pages mapped into the page table, resulting in
reported memory corruptions.
Most pageflags already have semantics for anonymous pages, however,
PG_mappedtodisk should never apply to pages in the swapcache, so let's
reuse that flag.
As PG_has_hwpoisoned also uses that flag on the second tail page of a
compound page, convert it to PG_error instead, which is marked as
PF_NO_TAIL, so never used for tail pages.
Use custom page flag modification functions such that we can do additional
sanity checks. The semantics we'll put into some kernel doc in the future
are:
"
PG_anon_exclusive is *usually* only expressive in combination with a
page table entry. Depending on the page table entry type it might
store the following information:
Is what's mapped via this page table entry exclusive to the
single process and can be mapped writable without further
checks? If not, it might be shared and we might have to COW.
For now, we only expect PTE-mapped THPs to make use of
PG_anon_exclusive in subpages. For other anonymous compound
folios (i.e., hugetlb), only the head page is logically mapped and
holds this information.
For example, an exclusive, PMD-mapped THP only has PG_anon_exclusive
set on the head page. When replacing the PMD by a page table full
of PTEs, PG_anon_exclusive, if set on the head page, will be set on
all tail pages accordingly. Note that converting from a PTE-mapping
to a PMD mapping using the same compound page is currently not
possible and consequently doesn't require care.
If GUP wants to take a reliable pin (FOLL_PIN) on an anonymous page,
it should only pin if the relevant PG_anon_exclusive is set. In that
case, the pin will be fully reliable and stay consistent with the pages
mapped into the page table, as the bit cannot get cleared (e.g., by
fork(), KSM) while the page is pinned. For anonymous pages that
are mapped R/W, PG_anon_exclusive can be assumed to always be set
because such pages cannot possibly be shared.
The page table lock protecting the page table entry is the primary
synchronization mechanism for PG_anon_exclusive; GUP-fast that does
not take the PT lock needs special care when trying to clear the
flag.
Page table entry types and PG_anon_exclusive:
* Present: PG_anon_exclusive applies.
* Swap: the information is lost. PG_anon_exclusive was cleared.
* Migration: the entry holds this information instead.
PG_anon_exclusive was cleared.
* Device private: PG_anon_exclusive applies.
* Device exclusive: PG_anon_exclusive applies.
* HW Poison: PG_anon_exclusive is stale and not changed.
If the page may be pinned (FOLL_PIN), clearing PG_anon_exclusive is
not allowed and the flag will stick around until the page is freed
and folio->mapping is cleared.
"
We won't be clearing PG_anon_exclusive on destructive unmapping (i.e.,
zapping) of page table entries, page freeing code will handle that when
also invalidate page->mapping to not indicate PageAnon() anymore. Letting
information about exclusivity stick around will be an important property
when adding sanity checks to unpinning code.
Note that we properly clear the flag in free_pages_prepare() via
PAGE_FLAGS_CHECK_AT_PREP for each individual subpage of a compound page,
so there is no need to manually clear the flag.
Link: https://lkml.kernel.org/r/20220428083441.37290-12-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Oded Gabbay <oded.gabbay@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
David Hildenbrand
|
6c54dc6c74 |
mm/rmap: use page_move_anon_rmap() when reusing a mapped PageAnon() page exclusively
We want to mark anonymous pages exclusive, and when using page_move_anon_rmap() we know that we are the exclusive user, as properly documented. This is a preparation for marking anonymous pages exclusive in page_move_anon_rmap(). In both instances, we're holding page lock and are sure that we're the exclusive owner (page_count() == 1). hugetlb already properly uses page_move_anon_rmap() in the write fault handler. Note that in case of a PTE-mapped THP, we'll only end up calling this function if the whole THP is only referenced by the single PTE mapping a single subpage (page_count() == 1); consequently, it's fine to modify the compound page mapping inside page_move_anon_rmap(). Link: https://lkml.kernel.org/r/20220428083441.37290-10-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Hildenbrand
|
40f2bbf711 |
mm/rmap: drop "compound" parameter from page_add_new_anon_rmap()
New anonymous pages are always mapped natively: only THP/khugepaged code maps a new compound anonymous page and passes "true". Otherwise, we're just dealing with simple, non-compound pages. Let's give the interface clearer semantics and document these. Remove the PageTransCompound() sanity check from page_add_new_anon_rmap(). Link: https://lkml.kernel.org/r/20220428083441.37290-9-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Hildenbrand
|
f1e2db12e4 |
mm/rmap: remove do_page_add_anon_rmap()
... and instead convert page_add_anon_rmap() to accept flags. Passing flags instead of bools is usually nicer either way, and we want to more often also pass RMAP_EXCLUSIVE in follow up patches when detecting that an anonymous page is exclusive: for example, when restoring an anonymous page from a writable migration entry. This is a preparation for marking an anonymous page inside page_add_anon_rmap() as exclusive when RMAP_EXCLUSIVE is passed. Link: https://lkml.kernel.org/r/20220428083441.37290-7-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Hildenbrand
|
14f9135d54 |
mm/rmap: convert RMAP flags to a proper distinct rmap_t type
We want to pass the flags to more than one anon rmap function, getting rid of special "do_page_add_anon_rmap()". So let's pass around a distinct __bitwise type and refine documentation. Link: https://lkml.kernel.org/r/20220428083441.37290-6-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Hildenbrand
|
fb3d824d1a |
mm/rmap: split page_dup_rmap() into page_dup_file_rmap() and page_try_dup_anon_rmap()
... and move the special check for pinned pages into page_try_dup_anon_rmap() to prepare for tracking exclusive anonymous pages via a new pageflag, clearing it only after making sure that there are no GUP pins on the anonymous page. We really only care about pins on anonymous pages, because they are prone to getting replaced in the COW handler once mapped R/O. For !anon pages in cow-mappings (!VM_SHARED && VM_MAYWRITE) we shouldn't really care about that, at least not that I could come up with an example. Let's drop the is_cow_mapping() check from page_needs_cow_for_dma(), as we know we're dealing with anonymous pages. Also, drop the handling of pinned pages from copy_huge_pud() and add a comment if ever supporting anonymous pages on the PUD level. This is a preparation for tracking exclusivity of anonymous pages in the rmap code, and disallowing marking a page shared (-> failing to duplicate) if there are GUP pins on a page. Link: https://lkml.kernel.org/r/20220428083441.37290-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
David Hildenbrand
|
b51ad4f867 |
mm/memory: slightly simplify copy_present_pte()
Let's move the pinning check into the caller, to simplify return code logic and prepare for further changes: relocating the page_needs_cow_for_dma() into rmap handling code. While at it, remove the unused pte parameter and simplify the comments a bit. No functional change intended. Link: https://lkml.kernel.org/r/20220428083441.37290-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <namit@vmware.com> Cc: Oded Gabbay <oded.gabbay@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Pedro Demarchi Gomes <pedrodemargomes@gmail.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Matthew Wilcox (Oracle)
|
7e0a126519 |
mm,fs: Remove aops->readpage
With all implementations of aops->readpage converted to aops->read_folio, we can stop checking whether it's set and remove the member from aops. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> |
||
|
Yang Yang
|
94bfe85bde |
mm/vmstat: add events for ksm cow
Users may use ksm by calling madvise(, , MADV_MERGEABLE) when they want to save memory, it's a tradeoff by suffering delay on ksm cow. Users can get to know how much memory ksm saved by reading /sys/kernel/mm/ksm/pages_sharing, but they don't know what's the costs of ksm cow, and this is important of some delay sensitive tasks. So add ksm cow events to help users evaluate whether or how to use ksm. Also update Documentation/admin-guide/mm/ksm.rst with new added events. Link: https://lkml.kernel.org/r/20220331035616.2390805-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang <yang.yang29@zte.com.cn> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: xu xin <xu.xin16@zte.com.cn> Reviewed-by: Ran Xiaokai <ran.xiaokai@zte.com.cn> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Saravanan D <saravanand@fb.com> Cc: Minchan Kim <minchan@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
Muchun Song
|
0e5e64c0b0 |
mm: simplify follow_invalidate_pte()
The only user (DAX) of range and pmdpp parameters of follow_invalidate_pte() is gone, it is safe to remove them and make it static to simlify the code. This is revertant of the following commits: |
||
Rik van Riel
|
3149c79f3c |
mm,hwpoison: unmap poisoned page before invalidation
In some cases it appears the invalidation of a hwpoisoned page fails
because the page is still mapped in another process. This can cause a
program to be continuously restarted and die when it page faults on the
page that was not invalidated. Avoid that problem by unmapping the
hwpoisoned page when we find it.
Another issue is that sometimes we end up oopsing in finish_fault, if
the code tries to do something with the now-NULL vmf->page. I did not
hit this error when submitting the previous patch because there are
several opportunities for alloc_set_pte to bail out before accessing
vmf->page, and that apparently happened on those systems, and most of
the time on other systems, too.
However, across several million systems that error does occur a handful
of times a day. It can be avoided by returning VM_FAULT_NOPAGE which
will cause do_read_fault to return before calling finish_fault.
Link: https://lkml.kernel.org/r/20220325161428.5068d97e@imladris.surriel.com
Fixes:
|
||
|
Hugh Dickins
|
2c86599516 |
mm: unmap_mapping_range_tree() with i_mmap_rwsem shared
Revert |
||
|
David Hildenbrand
|
c145e0b47c |
mm: streamline COW logic in do_swap_page()
Currently we have a different COW logic when: * triggering a read-fault to swapin first and then trigger a write-fault -> do_swap_page() + do_wp_page() * triggering a write-fault to swapin -> do_swap_page() + do_wp_page() only if we fail reuse in do_swap_page() The COW logic in do_swap_page() is different than our reuse logic in do_wp_page(). The COW logic in do_wp_page() -- page_count() == 1 -- makes currently sure that we certainly don't have a remaining reference, e.g., via GUP, on the target page we want to reuse: if there is any unexpected reference, we have to copy to avoid information leaks. As do_swap_page() behaves differently, in environments with swap enabled we can currently have an unintended information leak from the parent to the child, similar as known from CVE-2020-29374: 1. Parent writes to anonymous page -> Page is mapped writable and modified 2. Page is swapped out -> Page is unmapped and replaced by swap entry 3. fork() -> Swap entries are copied to child 4. Child pins page R/O -> Page is mapped R/O into child 5. Child unmaps page -> Child still holds GUP reference 6. Parent writes to page -> Page is reused in do_swap_page() -> Child can observe changes Exchanging 2. and 3. should have the same effect. Let's apply the same COW logic as in do_wp_page(), conditionally trying to remove the page from the swapcache after freeing the swap entry, however, before actually mapping our page. We can change the order now that we use try_to_free_swap(), which doesn't care about the mapcount, instead of reuse_swap_page(). To handle references from the LRU pagevecs, conditionally drain the local LRU pagevecs when required, however, don't consider the page_count() when deciding whether to drain to keep it simple for now. Link: https://lkml.kernel.org/r/20220131162940.210846-5-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
David Hildenbrand
|
84d60fdd37 |
mm: slightly clarify KSM logic in do_swap_page()
Let's make it clearer that KSM might only have to copy a page in case we have a page in the swapcache, not if we allocated a fresh page and bypassed the swapcache. While at it, add a comment why this is usually necessary and merge the two swapcache conditions. [akpm@linux-foundation.org: fix comment, per David] Link: https://lkml.kernel.org/r/20220131162940.210846-4-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: David Rientjes <rientjes@google.com> Cc: Don Dutile <ddutile@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Liang Zhang <zhangliang5@huawei.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeelb@google.com> Cc: Yang Shi <shy828301@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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David Hildenbrand
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d4c470970d |
mm: optimize do_wp_page() for fresh pages in local LRU pagevecs
For example, if a page just got swapped in via a read fault, the LRU
pagevecs might still hold a reference to the page. If we trigger a write
fault on such a page, the additional reference from the LRU pagevecs will
prohibit reusing the page.
Let's conditionally drain the local LRU pagevecs when we stumble over a
!PageLRU() page. We cannot easily drain remote LRU pagevecs and it might
not be desirable performance-wise. Consequently, this will only avoid
copying in some cases.
Add a simple "page_count(page) > 3" check first but keep the
"page_count(page) > 1 + PageSwapCache(page)" check in place, as we want to
minimize cases where we remove a page from the swapcache but won't be able
to reuse it, for example, because another process has it mapped R/O, to
not affect reclaim.
We cannot easily handle the following cases and we will always have to
copy:
(1) The page is referenced in the LRU pagevecs of other CPUs. We really
would have to drain the LRU pagevecs of all CPUs -- most probably
copying is much cheaper.
(2) The page is already PageLRU() but is getting moved between LRU
lists, for example, for activation (e.g., mark_page_accessed()),
deactivation (MADV_COLD), or lazyfree (MADV_FREE). We'd have to
drain mostly unconditionally, which might be bad performance-wise.
Most probably this won't happen too often in practice.
Note that there are other reasons why an anon page might temporarily not
be PageLRU(): for example, compaction and migration have to isolate LRU
pages from the LRU lists first (isolate_lru_page()), moving them to
temporary local lists and clearing PageLRU() and holding an additional
reference on the page. In that case, we'll always copy.
This change seems to be fairly effective with the reproducer [1] shared by
Nadav, as long as writeback is done synchronously, for example, using
zram. However, with asynchronous writeback, we'll usually fail to free
the swapcache because the page is still under writeback: something we
cannot easily optimize for, and maybe it's not really relevant in
practice.
[1] https://lkml.kernel.org/r/0480D692-D9B2-429A-9A88-9BBA1331AC3A@gmail.com
Link: https://lkml.kernel.org/r/20220131162940.210846-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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