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Author SHA1 Message Date
Mike Rapoport (Microsoft)
b0c4e27c68 mm: introduce numa_emulation 
Move numa_emulation code from arch/x86 to mm/numa_emulation.c

This code will be later reused by arch_numa.

No functional changes.

Link: https://lkml.kernel.org/r/20240807064110.1003856-20-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Zi Yan <ziy@nvidia.com> # for x86_64 and arm64
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [arm64 + CXL via QEMU]
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Rob Herring (Arm) <robh@kernel.org>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-03 21:15:31 -07:00
Mike Rapoport (Microsoft)
8748270821 mm: introduce numa_memblks 
Move code dealing with numa_memblks from arch/x86 to mm/ and add Kconfig
options to let x86 select it in its Kconfig.

This code will be later reused by arch_numa.

No functional changes.

Link: https://lkml.kernel.org/r/20240807064110.1003856-18-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Zi Yan <ziy@nvidia.com> # for x86_64 and arm64
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [arm64 + CXL via QEMU]
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Rob Herring (Arm) <robh@kernel.org>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-03 21:15:30 -07:00
Mike Rapoport (Microsoft)
0e8b67982b mm: move kernel/numa.c to mm/ 
Patch series "mm: introduce numa_memblks", v4.

Following the discussion about handling of CXL fixed memory windows on
arm64 [1] I decided to bite the bullet and move numa_memblks from x86 to
the generic code so they will be available on arm64/riscv and maybe on
loongarch sometime later.

While it could be possible to use memblock to describe CXL memory windows,
it currently lacks notion of unpopulated memory ranges and numa_memblks
does implement this.

Another reason to make numa_memblks generic is that both arch_numa (arm64
and riscv) and loongarch use trimmed copy of x86 code although there is no
fundamental reason why the same code cannot be used on all these
platforms.  Having numa_memblks in mm/ will make it's interaction with
ACPI and FDT more consistent and I believe will reduce maintenance burden.

And with generic numa_memblks it is (almost) straightforward to enable
NUMA emulation on arm64 and riscv.

The first 9 commits in this series are cleanups that are not strictly
related to numa_memblks.
Commits 10-16 slightly reorder code in x86 to allow extracting numa_memblks
and NUMA emulation to the generic code.
Commits 17-19 actually move the code from arch/x86/ to mm/ and commits 20-22
does some aftermath cleanups.
Commit 23 updates of_numa_init() to return error of no NUMA nodes were
found in the device tree.
Commit 24 switches arch_numa to numa_memblks.
Commit 25 enables usage of phys_to_target_node() and
memory_add_physaddr_to_nid() with numa_memblks.
Commit 26 moves the description for numa=fake from x86 to admin-guide.

[1] https://lore.kernel.org/all/20240529171236.32002-1-Jonathan.Cameron@huawei.com/


This patch (of 26):

The stub functions in kernel/numa.c belong to mm/ rather than to kernel/

Link: https://lkml.kernel.org/r/20240807064110.1003856-1-rppt@kernel.org
Link: https://lkml.kernel.org/r/20240807064110.1003856-2-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Tested-by: Zi Yan <ziy@nvidia.com> # for x86_64 and arm64
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> [arm64 + CXL via QEMU]
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Rob Herring (Arm) <robh@kernel.org>
Cc: Samuel Holland <samuel.holland@sifive.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-03 21:15:26 -07:00
Lorenzo Stoakes
49b1b8d6f6 mm: move internal core VMA manipulation functions to own file 
This patch introduces vma.c and moves internal core VMA manipulation
functions to this file from mmap.c.

This allows us to isolate VMA functionality in a single place such that we
can create userspace testing code that invokes this functionality in an
environment where we can implement simple unit tests of core
functionality.

This patch ensures that core VMA functionality is explicitly marked as
such by its presence in mm/vma.h.

It also places the header includes required by vma.c in vma_internal.h,
which is simply imported by vma.c.  This makes the VMA functionality
testable, as userland testing code can simply stub out functionality as
required.

Link: https://lkml.kernel.org/r/c77a6aafb4c42aaadb8e7271a853658cbdca2e22.1722251717.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Gow <davidgow@google.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kees Cook <kees@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Rae Moar <rmoar@google.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-01 20:25:54 -07:00
Carlos Maiolino
9eace7e8e6 shmem_quota: build the object file conditionally to the config option 
Initially I added shmem-quota to obj-y, move it to the correct place and
remove the unneeded full file #ifdef

Link: https://lkml.kernel.org/r/20240717063737.910840-1-cem@kernel.org
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Suggested-by: Aristeu Rozanski <aris@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-09-01 20:25:45 -07:00
Roman Gushchin
e93d4166b4 mm: memcg: put cgroup v1-specific code under a config option 
Put legacy cgroup v1 memory controller code under a new CONFIG_MEMCG_V1
config option.  The option is turned off by default.  Nobody except those
who are still using cgroup v1 should turn it on.

If the option is not set, memory controller can still be mounted under
cgroup v1, but none of memcg-specific control files are present.

Please note, that not all cgroup v1's memory controller code is guarded
yet (but most of it), it's a subject for some follow-up work.

Thanks to Michal Hocko for providing a better Kconfig option description.

[roman.gushchin@linux.dev: better config option description provided by Michal]
  Link: https://lkml.kernel.org/r/ZnxXNtvqllc9CDoo@google.com
Link: https://lkml.kernel.org/r/20240625005906.106920-14-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-04 18:05:54 -07:00
Roman Gushchin
1b1e13440c mm: memcg: introduce memcontrol-v1.c 
Patch series "mm: memcg: separate legacy cgroup v1 code and put under
config option", v2.

Cgroups v2 have been around for a while and many users have fully adopted
them, so they never use cgroups v1 features and functionality.  Yet they
have to "pay" for the cgroup v1 support anyway:
1) the kernel binary contains an unused cgroup v1 code,
2) some code paths have additional checks which are not needed,
3) some common structures like task_struct and mem_cgroup contain unused
   cgroup v1-specific members.

Cgroup v1's memory controller has a number of features that are not
supported by cgroup v2 and their implementation is pretty much self
contained.  Most notably, these features are: soft limit reclaim, oom
handling in userspace, complicated event notification system, charge
migration.  Cgroup v1-specific code in memcontrol.c is close to 4k lines
in size and it's intervened with generic and cgroup v2-specific code. 
It's a burden on developers and maintainers.

This patchset aims to solve these problems by:
1) moving cgroup v1-specific memcg code to the new mm/memcontrol-v1.c file,
2) putting definitions shared by memcontrol.c and memcontrol-v1.c into the
   mm/memcontrol-v1.h header,
3) introducing the CONFIG_MEMCG_V1 config option, turned off by default,
4) making memcontrol-v1.c to compile only if CONFIG_MEMCG_V1 is set.

If CONFIG_MEMCG_V1 is not set, cgroup v1 memory controller is still available
for mounting, however no memory-specific control knobs are present.

This patch (of 14):


This patch introduces the mm/memcontrol-v1.c source file which will be
used for all legacy (cgroup v1) memory cgroup code.  It also introduces
mm/memcontrol-v1.h to keep declarations shared between mm/memcontrol.c and
mm/memcontrol-v1.c.

As of now, let's compile it if CONFIG_MEMCG is set, similar to
mm/memcontrol.c.  Later on it can be switched to use a separate config
option, so that the legacy code won't be compiled if not required.

Link: https://lkml.kernel.org/r/20240625005906.106920-1-roman.gushchin@linux.dev
Link: https://lkml.kernel.org/r/20240625005906.106920-2-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-07-04 18:05:51 -07:00
Jeff Xu
8be7258aad mseal: add mseal syscall 
The new mseal() is an syscall on 64 bit CPU, and with following signature:

int mseal(void addr, size_t len, unsigned long flags)
addr/len: memory range.
flags: reserved.

mseal() blocks following operations for the given memory range.

1> Unmapping, moving to another location, and shrinking the size,
   via munmap() and mremap(), can leave an empty space, therefore can
   be replaced with a VMA with a new set of attributes.

2> Moving or expanding a different VMA into the current location,
   via mremap().

3> Modifying a VMA via mmap(MAP_FIXED).

4> Size expansion, via mremap(), does not appear to pose any specific
   risks to sealed VMAs. It is included anyway because the use case is
   unclear. In any case, users can rely on merging to expand a sealed VMA.

5> mprotect() and pkey_mprotect().

6> Some destructive madvice() behaviors (e.g. MADV_DONTNEED) for anonymous
   memory, when users don't have write permission to the memory. Those
   behaviors can alter region contents by discarding pages, effectively a
   memset(0) for anonymous memory.

Following input during RFC are incooperated into this patch:

Jann Horn: raising awareness and providing valuable insights on the
destructive madvise operations.
Linus Torvalds: assisting in defining system call signature and scope.
Liam R. Howlett: perf optimization.
Theo de Raadt: sharing the experiences and insight gained from
  implementing mimmutable() in OpenBSD.

Finally, the idea that inspired this patch comes from Stephen Röttger's
work in Chrome V8 CFI.

[jeffxu@chromium.org: add branch prediction hint, per Pedro]
  Link: https://lkml.kernel.org/r/20240423192825.1273679-2-jeffxu@chromium.org
Link: https://lkml.kernel.org/r/20240415163527.626541-3-jeffxu@chromium.org
Signed-off-by: Jeff Xu <jeffxu@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jorge Lucangeli Obes <jorgelo@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Stephen Röttger <sroettger@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Amer Al Shanawany <amer.shanawany@gmail.com>
Cc: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-05-23 19:40:26 -07:00
Linus Torvalds
61307b7be4 The usual shower of singleton fixes and minor series all over MM, 
documented (hopefully adequately) in the respective changelogs.  Notable
 series include:
 
 - Lucas Stach has provided some page-mapping
   cleanup/consolidation/maintainability work in the series "mm/treewide:
   Remove pXd_huge() API".
 
 - In the series "Allow migrate on protnone reference with
   MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
   MPOL_PREFERRED_MANY mode, yielding almost doubled performance in one
   test.
 
 - In their series "Memory allocation profiling" Kent Overstreet and
   Suren Baghdasaryan have contributed a means of determining (via
   /proc/allocinfo) whereabouts in the kernel memory is being allocated:
   number of calls and amount of memory.
 
 - Matthew Wilcox has provided the series "Various significant MM
   patches" which does a number of rather unrelated things, but in largely
   similar code sites.
 
 - In his series "mm: page_alloc: freelist migratetype hygiene" Johannes
   Weiner has fixed the page allocator's handling of migratetype requests,
   with resulting improvements in compaction efficiency.
 
 - In the series "make the hugetlb migration strategy consistent" Baolin
   Wang has fixed a hugetlb migration issue, which should improve hugetlb
   allocation reliability.
 
 - Liu Shixin has hit an I/O meltdown caused by readahead in a
   memory-tight memcg.  Addressed in the series "Fix I/O high when memory
   almost met memcg limit".
 
 - In the series "mm/filemap: optimize folio adding and splitting" Kairui
   Song has optimized pagecache insertion, yielding ~10% performance
   improvement in one test.
 
 - Baoquan He has cleaned up and consolidated the early zone
   initialization code in the series "mm/mm_init.c: refactor
   free_area_init_core()".
 
 - Baoquan has also redone some MM initializatio code in the series
   "mm/init: minor clean up and improvement".
 
 - MM helper cleanups from Christoph Hellwig in his series "remove
   follow_pfn".
 
 - More cleanups from Matthew Wilcox in the series "Various page->flags
   cleanups".
 
 - Vlastimil Babka has contributed maintainability improvements in the
   series "memcg_kmem hooks refactoring".
 
 - More folio conversions and cleanups in Matthew Wilcox's series
 
 	"Convert huge_zero_page to huge_zero_folio"
 	"khugepaged folio conversions"
 	"Remove page_idle and page_young wrappers"
 	"Use folio APIs in procfs"
 	"Clean up __folio_put()"
 	"Some cleanups for memory-failure"
 	"Remove page_mapping()"
 	"More folio compat code removal"
 
 - David Hildenbrand chipped in with "fs/proc/task_mmu: convert hugetlb
   functions to work on folis".
 
 - Code consolidation and cleanup work related to GUP's handling of
   hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".
 
 - Rick Edgecombe has developed some fixes to stack guard gaps in the
   series "Cover a guard gap corner case".
 
 - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the series
   "mm/ksm: fix ksm exec support for prctl".
 
 - Baolin Wang has implemented NUMA balancing for multi-size THPs.  This
   is a simple first-cut implementation for now.  The series is "support
   multi-size THP numa balancing".
 
 - Cleanups to vma handling helper functions from Matthew Wilcox in the
   series "Unify vma_address and vma_pgoff_address".
 
 - Some selftests maintenance work from Dev Jain in the series
   "selftests/mm: mremap_test: Optimizations and style fixes".
 
 - Improvements to the swapping of multi-size THPs from Ryan Roberts in
   the series "Swap-out mTHP without splitting".
 
 - Kefeng Wang has significantly optimized the handling of arm64's
   permission page faults in the series
 
 	"arch/mm/fault: accelerate pagefault when badaccess"
 	"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"
 
 - GUP cleanups from David Hildenbrand in "mm/gup: consistently call it
   GUP-fast".
 
 - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault path to
   use struct vm_fault".
 
 - selftests build fixes from John Hubbard in the series "Fix
   selftests/mm build without requiring "make headers"".
 
 - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
   series "Improved Memory Tier Creation for CPUless NUMA Nodes".  Fixes
   the initialization code so that migration between different memory types
   works as intended.
 
 - David Hildenbrand has improved follow_pte() and fixed an errant driver
   in the series "mm: follow_pte() improvements and acrn follow_pte()
   fixes".
 
 - David also did some cleanup work on large folio mapcounts in his
   series "mm: mapcount for large folios + page_mapcount() cleanups".
 
 - Folio conversions in KSM in Alex Shi's series "transfer page to folio
   in KSM".
 
 - Barry Song has added some sysfs stats for monitoring multi-size THP's
   in the series "mm: add per-order mTHP alloc and swpout counters".
 
 - Some zswap cleanups from Yosry Ahmed in the series "zswap same-filled
   and limit checking cleanups".
 
 - Matthew Wilcox has been looking at buffer_head code and found the
   documentation to be lacking.  The series is "Improve buffer head
   documentation".
 
 - Multi-size THPs get more work, this time from Lance Yang.  His series
   "mm/madvise: enhance lazyfreeing with mTHP in madvise_free" optimizes
   the freeing of these things.
 
 - Kemeng Shi has added more userspace-visible writeback instrumentation
   in the series "Improve visibility of writeback".
 
 - Kemeng Shi then sent some maintenance work on top in the series "Fix
   and cleanups to page-writeback".
 
 - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in the
   series "Improve anon_vma scalability for anon VMAs".  Intel's test bot
   reported an improbable 3x improvement in one test.
 
 - SeongJae Park adds some DAMON feature work in the series
 
 	"mm/damon: add a DAMOS filter type for page granularity access recheck"
 	"selftests/damon: add DAMOS quota goal test"
 
 - Also some maintenance work in the series
 
 	"mm/damon/paddr: simplify page level access re-check for pageout"
 	"mm/damon: misc fixes and improvements"
 
 - David Hildenbrand has disabled some known-to-fail selftests ni the
   series "selftests: mm: cow: flag vmsplice() hugetlb tests as XFAIL".
 
 - memcg metadata storage optimizations from Shakeel Butt in "memcg:
   reduce memory consumption by memcg stats".
 
 - DAX fixes and maintenance work from Vishal Verma in the series
   "dax/bus.c: Fixups for dax-bus locking".
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Merge tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull mm updates from Andrew Morton:
 "The usual shower of singleton fixes and minor series all over MM,
  documented (hopefully adequately) in the respective changelogs.
  Notable series include:

   - Lucas Stach has provided some page-mapping cleanup/consolidation/
     maintainability work in the series "mm/treewide: Remove pXd_huge()
     API".

   - In the series "Allow migrate on protnone reference with
     MPOL_PREFERRED_MANY policy", Donet Tom has optimized mempolicy's
     MPOL_PREFERRED_MANY mode, yielding almost doubled performance in
     one test.

   - In their series "Memory allocation profiling" Kent Overstreet and
     Suren Baghdasaryan have contributed a means of determining (via
     /proc/allocinfo) whereabouts in the kernel memory is being
     allocated: number of calls and amount of memory.

   - Matthew Wilcox has provided the series "Various significant MM
     patches" which does a number of rather unrelated things, but in
     largely similar code sites.

   - In his series "mm: page_alloc: freelist migratetype hygiene"
     Johannes Weiner has fixed the page allocator's handling of
     migratetype requests, with resulting improvements in compaction
     efficiency.

   - In the series "make the hugetlb migration strategy consistent"
     Baolin Wang has fixed a hugetlb migration issue, which should
     improve hugetlb allocation reliability.

   - Liu Shixin has hit an I/O meltdown caused by readahead in a
     memory-tight memcg. Addressed in the series "Fix I/O high when
     memory almost met memcg limit".

   - In the series "mm/filemap: optimize folio adding and splitting"
     Kairui Song has optimized pagecache insertion, yielding ~10%
     performance improvement in one test.

   - Baoquan He has cleaned up and consolidated the early zone
     initialization code in the series "mm/mm_init.c: refactor
     free_area_init_core()".

   - Baoquan has also redone some MM initializatio code in the series
     "mm/init: minor clean up and improvement".

   - MM helper cleanups from Christoph Hellwig in his series "remove
     follow_pfn".

   - More cleanups from Matthew Wilcox in the series "Various
     page->flags cleanups".

   - Vlastimil Babka has contributed maintainability improvements in the
     series "memcg_kmem hooks refactoring".

   - More folio conversions and cleanups in Matthew Wilcox's series:
	"Convert huge_zero_page to huge_zero_folio"
	"khugepaged folio conversions"
	"Remove page_idle and page_young wrappers"
	"Use folio APIs in procfs"
	"Clean up __folio_put()"
	"Some cleanups for memory-failure"
	"Remove page_mapping()"
	"More folio compat code removal"

   - David Hildenbrand chipped in with "fs/proc/task_mmu: convert
     hugetlb functions to work on folis".

   - Code consolidation and cleanup work related to GUP's handling of
     hugetlbs in Peter Xu's series "mm/gup: Unify hugetlb, part 2".

   - Rick Edgecombe has developed some fixes to stack guard gaps in the
     series "Cover a guard gap corner case".

   - Jinjiang Tu has fixed KSM's behaviour after a fork+exec in the
     series "mm/ksm: fix ksm exec support for prctl".

   - Baolin Wang has implemented NUMA balancing for multi-size THPs.
     This is a simple first-cut implementation for now. The series is
     "support multi-size THP numa balancing".

   - Cleanups to vma handling helper functions from Matthew Wilcox in
     the series "Unify vma_address and vma_pgoff_address".

   - Some selftests maintenance work from Dev Jain in the series
     "selftests/mm: mremap_test: Optimizations and style fixes".

   - Improvements to the swapping of multi-size THPs from Ryan Roberts
     in the series "Swap-out mTHP without splitting".

   - Kefeng Wang has significantly optimized the handling of arm64's
     permission page faults in the series
	"arch/mm/fault: accelerate pagefault when badaccess"
	"mm: remove arch's private VM_FAULT_BADMAP/BADACCESS"

   - GUP cleanups from David Hildenbrand in "mm/gup: consistently call
     it GUP-fast".

   - hugetlb fault code cleanups from Vishal Moola in "Hugetlb fault
     path to use struct vm_fault".

   - selftests build fixes from John Hubbard in the series "Fix
     selftests/mm build without requiring "make headers"".

   - Memory tiering fixes/improvements from Ho-Ren (Jack) Chuang in the
     series "Improved Memory Tier Creation for CPUless NUMA Nodes".
     Fixes the initialization code so that migration between different
     memory types works as intended.

   - David Hildenbrand has improved follow_pte() and fixed an errant
     driver in the series "mm: follow_pte() improvements and acrn
     follow_pte() fixes".

   - David also did some cleanup work on large folio mapcounts in his
     series "mm: mapcount for large folios + page_mapcount() cleanups".

   - Folio conversions in KSM in Alex Shi's series "transfer page to
     folio in KSM".

   - Barry Song has added some sysfs stats for monitoring multi-size
     THP's in the series "mm: add per-order mTHP alloc and swpout
     counters".

   - Some zswap cleanups from Yosry Ahmed in the series "zswap
     same-filled and limit checking cleanups".

   - Matthew Wilcox has been looking at buffer_head code and found the
     documentation to be lacking. The series is "Improve buffer head
     documentation".

   - Multi-size THPs get more work, this time from Lance Yang. His
     series "mm/madvise: enhance lazyfreeing with mTHP in madvise_free"
     optimizes the freeing of these things.

   - Kemeng Shi has added more userspace-visible writeback
     instrumentation in the series "Improve visibility of writeback".

   - Kemeng Shi then sent some maintenance work on top in the series
     "Fix and cleanups to page-writeback".

   - Matthew Wilcox reduces mmap_lock traffic in the anon vma code in
     the series "Improve anon_vma scalability for anon VMAs". Intel's
     test bot reported an improbable 3x improvement in one test.

   - SeongJae Park adds some DAMON feature work in the series
	"mm/damon: add a DAMOS filter type for page granularity access recheck"
	"selftests/damon: add DAMOS quota goal test"

   - Also some maintenance work in the series
	"mm/damon/paddr: simplify page level access re-check for pageout"
	"mm/damon: misc fixes and improvements"

   - David Hildenbrand has disabled some known-to-fail selftests ni the
     series "selftests: mm: cow: flag vmsplice() hugetlb tests as
     XFAIL".

   - memcg metadata storage optimizations from Shakeel Butt in "memcg:
     reduce memory consumption by memcg stats".

   - DAX fixes and maintenance work from Vishal Verma in the series
     "dax/bus.c: Fixups for dax-bus locking""

* tag 'mm-stable-2024-05-17-19-19' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (426 commits)
  memcg, oom: cleanup unused memcg_oom_gfp_mask and memcg_oom_order
  selftests/mm: hugetlb_madv_vs_map: avoid test skipping by querying hugepage size at runtime
  mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_wp
  mm/hugetlb: add missing VM_FAULT_SET_HINDEX in hugetlb_fault
  selftests: cgroup: add tests to verify the zswap writeback path
  mm: memcg: make alloc_mem_cgroup_per_node_info() return bool
  mm/damon/core: fix return value from damos_wmark_metric_value
  mm: do not update memcg stats for NR_{FILE/SHMEM}_PMDMAPPED
  selftests: cgroup: remove redundant enabling of memory controller
  Docs/mm/damon/maintainer-profile: allow posting patches based on damon/next tree
  Docs/mm/damon/maintainer-profile: change the maintainer's timezone from PST to PT
  Docs/mm/damon/design: use a list for supported filters
  Docs/admin-guide/mm/damon/usage: fix wrong schemes effective quota update command
  Docs/admin-guide/mm/damon/usage: fix wrong example of DAMOS filter matching sysfs file
  selftests/damon: classify tests for functionalities and regressions
  selftests/damon/_damon_sysfs: use 'is' instead of '==' for 'None'
  selftests/damon/_damon_sysfs: find sysfs mount point from /proc/mounts
  selftests/damon/_damon_sysfs: check errors from nr_schemes file reads
  mm/damon/core: initialize ->esz_bp from damos_quota_init_priv()
  selftests/damon: add a test for DAMOS quota goal
  ...
 2024-05-19 09:21:03 -07:00
Mike Rapoport (IBM)
12af2b83d0 mm: introduce execmem_alloc() and execmem_free() 
module_alloc() is used everywhere as a mean to allocate memory for code.

Beside being semantically wrong, this unnecessarily ties all subsystems
that need to allocate code, such as ftrace, kprobes and BPF to modules and
puts the burden of code allocation to the modules code.

Several architectures override module_alloc() because of various
constraints where the executable memory can be located and this causes
additional obstacles for improvements of code allocation.

Start splitting code allocation from modules by introducing execmem_alloc()
and execmem_free() APIs.

Initially, execmem_alloc() is a wrapper for module_alloc() and
execmem_free() is a replacement of module_memfree() to allow updating all
call sites to use the new APIs.

Since architectures define different restrictions on placement,
permissions, alignment and other parameters for memory that can be used by
different subsystems that allocate executable memory, execmem_alloc() takes
a type argument, that will be used to identify the calling subsystem and to
allow architectures define parameters for ranges suitable for that
subsystem.

No functional changes.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
 2024-05-14 00:31:43 -07:00
Waiman Long
c8d36bc2df mm/kmemleak: disable KASAN instrumentation in kmemleak 
Kmemleak ia a memory leak checker.  KASAN is also a memory checker but it
focuses more on finding out-of-bounds and use-after-free bugs.  Since
kmemleak is inherently slow especially on systems with large number of
CPUs, adding KASAN instrumentation will make it slower even more.  As
kmemleak is not for production use, the utility of enabling KASAN there is
questionable.

This patch disables KASAN instrumentation for configurations that enable
both of them to slightly reduce performance overhead.

Link: https://lkml.kernel.org/r/20240307190548.963626-3-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2024-04-25 20:56:05 -07:00
Arnd Bergmann
c40845e319 kbuild: make -Woverride-init warnings more consistent 
The -Woverride-init warn about code that may be intentional or not,
but the inintentional ones tend to be real bugs, so there is a bit of
disagreement on whether this warning option should be enabled by default
and we have multiple settings in scripts/Makefile.extrawarn as well as
individual subsystems.

Older versions of clang only supported -Wno-initializer-overrides with
the same meaning as gcc's -Woverride-init, though all supported versions
now work with both. Because of this difference, an earlier cleanup of
mine accidentally turned the clang warning off for W=1 builds and only
left it on for W=2, while it's still enabled for gcc with W=1.

There is also one driver that only turns the warning off for newer
versions of gcc but not other compilers, and some but not all the
Makefiles still use a cc-disable-warning conditional that is no
longer needed with supported compilers here.

Address all of the above by removing the special cases for clang
and always turning the warning off unconditionally where it got
in the way, using the syntax that is supported by both compilers.

Fixes: 2cd3271b7a ("kbuild: avoid duplicate warning options")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
 2024-03-31 11:32:26 +09:00
Vlastimil Babka
2a19be61a6 mm/slab: remove CONFIG_SLAB from all Kconfig and Makefile 
Remove CONFIG_SLAB, CONFIG_DEBUG_SLAB, CONFIG_SLAB_DEPRECATED and
everything in Kconfig files and mm/Makefile that depends on those. Since
SLUB is the only remaining allocator, remove the allocator choice, make
CONFIG_SLUB a "def_bool y" for now and remove all explicit dependencies
on SLUB or SLAB as it's now always enabled. Make every option's verbose
name and description refer to "the slab allocator" without refering to
the specific implementation. Do not rename the CONFIG_ option names yet.

Everything under #ifdef CONFIG_SLAB, and mm/slab.c is now dead code, all
code under #ifdef CONFIG_SLUB is now always compiled.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Tested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
 2023-12-05 11:14:40 +01:00
Qi Zheng
96f7b2b9bb mm: vmscan: move shrinker-related code into a separate file 
The mm/vmscan.c file is too large, so separate the shrinker-related code
from it into a separate file.  No functional changes.

Link: https://lkml.kernel.org/r/20230911092517.64141-3-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sean Paul <sean@poorly.run>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-10-04 10:32:23 -07:00
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
  ...
 2023-08-29 14:25:26 -07:00
Johannes Weiner
42c06a0e8e mm: kill frontswap 
The only user of frontswap is zswap, and has been for a long time.  Have
swap call into zswap directly and remove the indirection.

[hannes@cmpxchg.org: remove obsolete comment, per Yosry]
  Link: https://lkml.kernel.org/r/20230719142832.GA932528@cmpxchg.org
[fengwei.yin@intel.com: don't warn if none swapcache folio is passed to zswap_load]
  Link: https://lkml.kernel.org/r/20230810095652.3905184-1-fengwei.yin@intel.com
Link: https://lkml.kernel.org/r/20230717160227.GA867137@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-08-21 13:37:26 -07:00
Carlos Maiolino
eafc474e20 shmem: prepare shmem quota infrastructure 
Add new shmem quota format, its quota_format_ops together with
dquot_operations

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Message-Id: <20230725144510.253763-5-cem@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
 2023-08-09 09:15:39 +02:00
Kefeng Wang
884c175f12 mm: page_alloc: split out DEBUG_PAGEALLOC 
Move DEBUG_PAGEALLOC related functions into a single file to reduce a bit
of page_alloc.c.

Link: https://lkml.kernel.org/r/20230516063821.121844-9-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: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-06-09 16:25:23 -07:00
Kefeng Wang
0866e82e40 mm: page_alloc: split out FAIL_PAGE_ALLOC 
... to a single file to reduce a bit of page_alloc.c.

Link: https://lkml.kernel.org/r/20230516063821.121844-8-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: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-06-09 16:25:23 -07:00
Kefeng Wang
e9aae17092 mm: page_alloc: collect mem statistic into show_mem.c 
Let's move show_mem.c from lib to mm, as it belongs memory subsystem, also
split some memory statistic related functions from page_alloc.c to
show_mem.c, and we cleanup some unneeded include.

There is no functional change.

Link: https://lkml.kernel.org/r/20230516063821.121844-5-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: Iurii Zaikin <yzaikin@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-06-09 16:25:22 -07:00
Linus Torvalds
7fa8a8ee94 - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of 
switching from a user process to a kernel thread.
 
 - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj Raghav.
 
 - zsmalloc performance improvements from Sergey Senozhatsky.
 
 - Yue Zhao has found and fixed some data race issues around the
   alteration of memcg userspace tunables.
 
 - VFS rationalizations from Christoph Hellwig:
 
   - removal of most of the callers of write_one_page().
 
   - make __filemap_get_folio()'s return value more useful
 
 - Luis Chamberlain has changed tmpfs so it no longer requires swap
   backing.  Use `mount -o noswap'.
 
 - Qi Zheng has made the slab shrinkers operate locklessly, providing
   some scalability benefits.
 
 - Keith Busch has improved dmapool's performance, making part of its
   operations O(1) rather than O(n).
 
 - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
   permitting userspace to wr-protect anon memory unpopulated ptes.
 
 - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive rather
   than exclusive, and has fixed a bunch of errors which were caused by its
   unintuitive meaning.
 
 - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
   which causes minor faults to install a write-protected pte.
 
 - Vlastimil Babka has done some maintenance work on vma_merge():
   cleanups to the kernel code and improvements to our userspace test
   harness.
 
 - Cleanups to do_fault_around() by Lorenzo Stoakes.
 
 - Mike Rapoport has moved a lot of initialization code out of various
   mm/ files and into mm/mm_init.c.
 
 - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
   DRM, but DRM doesn't use it any more.
 
 - Lorenzo has also coverted read_kcore() and vread() to use iterators
   and has thereby removed the use of bounce buffers in some cases.
 
 - Lorenzo has also contributed further cleanups of vma_merge().
 
 - Chaitanya Prakash provides some fixes to the mmap selftesting code.
 
 - Matthew Wilcox changes xfs and afs so they no longer take sleeping
   locks in ->map_page(), a step towards RCUification of pagefaults.
 
 - Suren Baghdasaryan has improved mmap_lock scalability by switching to
   per-VMA locking.
 
 - Frederic Weisbecker has reworked the percpu cache draining so that it
   no longer causes latency glitches on cpu isolated workloads.
 
 - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
   logic.
 
 - Liu Shixin has changed zswap's initialization so we no longer waste a
   chunk of memory if zswap is not being used.
 
 - Yosry Ahmed has improved the performance of memcg statistics flushing.
 
 - David Stevens has fixed several issues involving khugepaged,
   userfaultfd and shmem.
 
 - Christoph Hellwig has provided some cleanup work to zram's IO-related
   code paths.
 
 - David Hildenbrand has fixed up some issues in the selftest code's
   testing of our pte state changing.
 
 - Pankaj Raghav has made page_endio() unneeded and has removed it.
 
 - Peter Xu contributed some rationalizations of the userfaultfd
   selftests.
 
 - Yosry Ahmed has fixed an issue around memcg's page recalim accounting.
 
 - Chaitanya Prakash has fixed some arm-related issues in the
   selftests/mm code.
 
 - Longlong Xia has improved the way in which KSM handles hwpoisoned
   pages.
 
 - Peter Xu fixes a few issues with uffd-wp at fork() time.
 
 - Stefan Roesch has changed KSM so that it may now be used on a
   per-process and per-cgroup basis.
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Merge tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Nick Piggin's "shoot lazy tlbs" series, to improve the peformance of
   switching from a user process to a kernel thread.

 - More folio conversions from Kefeng Wang, Zhang Peng and Pankaj
   Raghav.

 - zsmalloc performance improvements from Sergey Senozhatsky.

 - Yue Zhao has found and fixed some data race issues around the
   alteration of memcg userspace tunables.

 - VFS rationalizations from Christoph Hellwig:
     - removal of most of the callers of write_one_page()
     - make __filemap_get_folio()'s return value more useful

 - Luis Chamberlain has changed tmpfs so it no longer requires swap
   backing. Use `mount -o noswap'.

 - Qi Zheng has made the slab shrinkers operate locklessly, providing
   some scalability benefits.

 - Keith Busch has improved dmapool's performance, making part of its
   operations O(1) rather than O(n).

 - Peter Xu adds the UFFD_FEATURE_WP_UNPOPULATED feature to userfaultd,
   permitting userspace to wr-protect anon memory unpopulated ptes.

 - Kirill Shutemov has changed MAX_ORDER's meaning to be inclusive
   rather than exclusive, and has fixed a bunch of errors which were
   caused by its unintuitive meaning.

 - Axel Rasmussen give userfaultfd the UFFDIO_CONTINUE_MODE_WP feature,
   which causes minor faults to install a write-protected pte.

 - Vlastimil Babka has done some maintenance work on vma_merge():
   cleanups to the kernel code and improvements to our userspace test
   harness.

 - Cleanups to do_fault_around() by Lorenzo Stoakes.

 - Mike Rapoport has moved a lot of initialization code out of various
   mm/ files and into mm/mm_init.c.

 - Lorenzo Stoakes removd vmf_insert_mixed_prot(), which was added for
   DRM, but DRM doesn't use it any more.

 - Lorenzo has also coverted read_kcore() and vread() to use iterators
   and has thereby removed the use of bounce buffers in some cases.

 - Lorenzo has also contributed further cleanups of vma_merge().

 - Chaitanya Prakash provides some fixes to the mmap selftesting code.

 - Matthew Wilcox changes xfs and afs so they no longer take sleeping
   locks in ->map_page(), a step towards RCUification of pagefaults.

 - Suren Baghdasaryan has improved mmap_lock scalability by switching to
   per-VMA locking.

 - Frederic Weisbecker has reworked the percpu cache draining so that it
   no longer causes latency glitches on cpu isolated workloads.

 - Mike Rapoport cleans up and corrects the ARCH_FORCE_MAX_ORDER Kconfig
   logic.

 - Liu Shixin has changed zswap's initialization so we no longer waste a
   chunk of memory if zswap is not being used.

 - Yosry Ahmed has improved the performance of memcg statistics
   flushing.

 - David Stevens has fixed several issues involving khugepaged,
   userfaultfd and shmem.

 - Christoph Hellwig has provided some cleanup work to zram's IO-related
   code paths.

 - David Hildenbrand has fixed up some issues in the selftest code's
   testing of our pte state changing.

 - Pankaj Raghav has made page_endio() unneeded and has removed it.

 - Peter Xu contributed some rationalizations of the userfaultfd
   selftests.

 - Yosry Ahmed has fixed an issue around memcg's page recalim
   accounting.

 - Chaitanya Prakash has fixed some arm-related issues in the
   selftests/mm code.

 - Longlong Xia has improved the way in which KSM handles hwpoisoned
   pages.

 - Peter Xu fixes a few issues with uffd-wp at fork() time.

 - Stefan Roesch has changed KSM so that it may now be used on a
   per-process and per-cgroup basis.

* tag 'mm-stable-2023-04-27-15-30' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (369 commits)
  mm,unmap: avoid flushing TLB in batch if PTE is inaccessible
  shmem: restrict noswap option to initial user namespace
  mm/khugepaged: fix conflicting mods to collapse_file()
  sparse: remove unnecessary 0 values from rc
  mm: move 'mmap_min_addr' logic from callers into vm_unmapped_area()
  hugetlb: pte_alloc_huge() to replace huge pte_alloc_map()
  maple_tree: fix allocation in mas_sparse_area()
  mm: do not increment pgfault stats when page fault handler retries
  zsmalloc: allow only one active pool compaction context
  selftests/mm: add new selftests for KSM
  mm: add new KSM process and sysfs knobs
  mm: add new api to enable ksm per process
  mm: shrinkers: fix debugfs file permissions
  mm: don't check VMA write permissions if the PTE/PMD indicates write permissions
  migrate_pages_batch: fix statistics for longterm pin retry
  userfaultfd: use helper function range_in_vma()
  lib/show_mem.c: use for_each_populated_zone() simplify code
  mm: correct arg in reclaim_pages()/reclaim_clean_pages_from_list()
  fs/buffer: convert create_page_buffers to folio_create_buffers
  fs/buffer: add folio_create_empty_buffers helper
  ...
 2023-04-27 19:42:02 -07:00
Keith Busch
def8574308 dmapool: add alloc/free performance test 
Patch series "dmapool enhancements", v4.

Time spent in dma_pool alloc/free increases linearly with the number of
pages backing the pool.  We can reduce this to constant time with minor
changes to how free pages are tracked.


This patch (of 12):

Provide a module that allocates and frees many blocks of various sizes and
report how long it takes.  This is intended to provide a consistent way to
measure how changes to the dma_pool_alloc/free routines affect timing.

Link: https://lkml.kernel.org/r/20230126215125.4069751-1-kbusch@meta.com
Link: https://lkml.kernel.org/r/20230126215125.4069751-2-kbusch@meta.com
Signed-off-by: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2023-04-05 19:42:38 -07:00
Vlastimil Babka
c9929f0e34 mm/slob: remove CONFIG_SLOB 
Remove SLOB from Kconfig and Makefile. Everything under #ifdef
CONFIG_SLOB, and mm/slob.c is now dead code.

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Acked-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
 2023-03-29 10:31:40 +02:00
Johannes Weiner
e55b9f9686 mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol 
Since 2d1c498072 ("mm: memcontrol: make swap tracking an integral part
of memory control"), CONFIG_MEMCG_SWAP hasn't been a user-visible config
option anymore, it just means CONFIG_MEMCG && CONFIG_SWAP.

Update the sites accordingly and drop the symbol.

[ While touching the docs, remove two references to CONFIG_MEMCG_KMEM,
  which hasn't been a user-visible symbol for over half a decade. ]

Link: https://lkml.kernel.org/r/20220926135704.400818-5-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-10-03 14:03:36 -07:00
Alexander Potapenko
f80be4571b kmsan: add KMSAN runtime core 
For each memory location KernelMemorySanitizer maintains two types of
metadata:

1. The so-called shadow of that location - а byte:byte mapping describing
   whether or not individual bits of memory are initialized (shadow is 0)
   or not (shadow is 1).
2. The origins of that location - а 4-byte:4-byte mapping containing
   4-byte IDs of the stack traces where uninitialized values were
   created.

Each struct page now contains pointers to two struct pages holding KMSAN
metadata (shadow and origins) for the original struct page.  Utility
routines in mm/kmsan/core.c and mm/kmsan/shadow.c handle the metadata
creation, addressing, copying and checking.  mm/kmsan/report.c performs
error reporting in the cases an uninitialized value is used in a way that
leads to undefined behavior.

KMSAN compiler instrumentation is responsible for tracking the metadata
along with the kernel memory.  mm/kmsan/instrumentation.c provides the
implementation for instrumentation hooks that are called from files
compiled with -fsanitize=kernel-memory.

To aid parameter passing (also done at instrumentation level), each
task_struct now contains a struct kmsan_task_state used to track the
metadata of function parameters and return values for that task.

Finally, this patch provides CONFIG_KMSAN that enables KMSAN, and declares
CFLAGS_KMSAN, which are applied to files compiled with KMSAN.  The
KMSAN_SANITIZE:=n Makefile directive can be used to completely disable
KMSAN instrumentation for certain files.

Similarly, KMSAN_ENABLE_CHECKS:=n disables KMSAN checks and makes newly
created stack memory initialized.

Users can also use functions from include/linux/kmsan-checks.h to mark
certain memory regions as uninitialized or initialized (this is called
"poisoning" and "unpoisoning") or check that a particular region is
initialized.

Link: https://lkml.kernel.org/r/20220915150417.722975-12-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Marco Elver <elver@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: 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>
 2022-10-03 14:03:19 -07:00
Liam R. Howlett
7964cf8caa mm: remove vmacache 
By using the maple tree and the maple tree state, the vmacache is no
longer beneficial and is complicating the VMA code.  Remove the vmacache
to reduce the work in keeping it up to date and code complexity.

Link: https://lkml.kernel.org/r/20220906194824.2110408-26-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
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: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-09-26 19:46:18 -07:00
Aneesh Kumar K.V
992bf77591 mm/demotion: add support for explicit memory tiers 
Patch series "mm/demotion: Memory tiers and demotion", v15.

The current kernel has the basic memory tiering support: Inactive pages on
a higher tier NUMA node can be migrated (demoted) to a lower tier NUMA
node to make room for new allocations on the higher tier NUMA node. 
Frequently accessed pages on a lower tier NUMA node can be migrated
(promoted) to a higher tier NUMA node to improve the performance.

In the current kernel, memory tiers are defined implicitly via a demotion
path relationship between NUMA nodes, which is created during the kernel
initialization and updated when a NUMA node is hot-added or hot-removed. 
The current implementation puts all nodes with CPU into the highest tier,
and builds the tier hierarchy tier-by-tier by establishing the per-node
demotion targets based on the distances between nodes.

This current memory tier kernel implementation needs to be improved for
several important use cases:

* The current tier initialization code always initializes each
  memory-only NUMA node into a lower tier.  But a memory-only NUMA node
  may have a high performance memory device (e.g.  a DRAM-backed
  memory-only node on a virtual machine) and that should be put into a
  higher tier.

* The current tier hierarchy always puts CPU nodes into the top tier. 
  But on a system with HBM (e.g.  GPU memory) devices, these memory-only
  HBM NUMA nodes should be in the top tier, and DRAM nodes with CPUs are
  better to be placed into the next lower tier.

* Also because the current tier hierarchy always puts CPU nodes into the
  top tier, when a CPU is hot-added (or hot-removed) and triggers a memory
  node from CPU-less into a CPU node (or vice versa), the memory tier
  hierarchy gets changed, even though no memory node is added or removed. 
  This can make the tier hierarchy unstable and make it difficult to
  support tier-based memory accounting.

* A higher tier node can only be demoted to nodes with shortest distance
  on the next lower tier as defined by the demotion path, not any other
  node from any lower tier.  This strict, demotion order does not work in
  all use cases (e.g.  some use cases may want to allow cross-socket
  demotion to another node in the same demotion tier as a fallback when
  the preferred demotion node is out of space), and has resulted in the
  feature request for an interface to override the system-wide, per-node
  demotion order from the userspace.  This demotion order is also
  inconsistent with the page allocation fallback order when all the nodes
  in a higher tier are out of space: The page allocation can fall back to
  any node from any lower tier, whereas the demotion order doesn't allow
  that.

This patch series make the creation of memory tiers explicit under the
control of device driver.

Memory Tier Initialization
==========================

Linux kernel presents memory devices as NUMA nodes and each memory device
is of a specific type.  The memory type of a device is represented by its
abstract distance.  A memory tier corresponds to a range of abstract
distance.  This allows for classifying memory devices with a specific
performance range into a memory tier.

By default, all memory nodes are assigned to the default tier with
abstract distance 512.

A device driver can move its memory nodes from the default tier.  For
example, PMEM can move its memory nodes below the default tier, whereas
GPU can move its memory nodes above the default tier.

The kernel initialization code makes the decision on which exact tier a
memory node should be assigned to based on the requests from the device
drivers as well as the memory device hardware information provided by the
firmware.

Hot-adding/removing CPUs doesn't affect memory tier hierarchy.


This patch (of 10):

In the current kernel, memory tiers are defined implicitly via a demotion
path relationship between NUMA nodes, which is created during the kernel
initialization and updated when a NUMA node is hot-added or hot-removed. 
The current implementation puts all nodes with CPU into the highest tier,
and builds the tier hierarchy by establishing the per-node demotion
targets based on the distances between nodes.

This current memory tier kernel implementation needs to be improved for
several important use cases,

The current tier initialization code always initializes each memory-only
NUMA node into a lower tier.  But a memory-only NUMA node may have a high
performance memory device (e.g.  a DRAM-backed memory-only node on a
virtual machine) that should be put into a higher tier.

The current tier hierarchy always puts CPU nodes into the top tier.  But
on a system with HBM or GPU devices, the memory-only NUMA nodes mapping
these devices should be in the top tier, and DRAM nodes with CPUs are
better to be placed into the next lower tier.

With current kernel higher tier node can only be demoted to nodes with
shortest distance on the next lower tier as defined by the demotion path,
not any other node from any lower tier.  This strict, demotion order does
not work in all use cases (e.g.  some use cases may want to allow
cross-socket demotion to another node in the same demotion tier as a
fallback when the preferred demotion node is out of space), This demotion
order is also inconsistent with the page allocation fallback order when
all the nodes in a higher tier are out of space: The page allocation can
fall back to any node from any lower tier, whereas the demotion order
doesn't allow that.

This patch series address the above by defining memory tiers explicitly.

Linux kernel presents memory devices as NUMA nodes and each memory device
is of a specific type.  The memory type of a device is represented by its
abstract distance.  A memory tier corresponds to a range of abstract
distance.  This allows for classifying memory devices with a specific
performance range into a memory tier.

This patch configures the range/chunk size to be 128.  The default DRAM
abstract distance is 512.  We can have 4 memory tiers below the default
DRAM with abstract distance range 0 - 127, 127 - 255, 256- 383, 384 - 511.
Faster memory devices can be placed in these faster(higher) memory tiers.
Slower memory devices like persistent memory will have abstract distance
higher than the default DRAM level.

[akpm@linux-foundation.org: fix comment, per Aneesh]
Link: https://lkml.kernel.org/r/20220818131042.113280-1-aneesh.kumar@linux.ibm.com
Link: https://lkml.kernel.org/r/20220818131042.113280-2-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: 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: Jagdish Gediya <jvgediya.oss@gmail.com>
Cc: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-09-26 19:46:11 -07:00
Roman Gushchin
5035ebc644 mm: shrinkers: introduce debugfs interface for memory shrinkers 
This commit introduces the /sys/kernel/debug/shrinker debugfs interface
which provides an ability to observe the state of individual kernel memory
shrinkers.

Because the feature adds some memory overhead (which shouldn't be large
unless there is a huge amount of registered shrinkers), it's guarded by a
config option (enabled by default).

This commit introduces the "count" interface for each shrinker registered
in the system.

The output is in the following format:
<cgroup inode id> <nr of objects on node 0> <nr of objects on node 1>...
<cgroup inode id> <nr of objects on node 0> <nr of objects on node 1>...
...

To reduce the size of output on machines with many thousands cgroups, if
the total number of objects on all nodes is 0, the line is omitted.

If the shrinker is not memcg-aware or CONFIG_MEMCG is off, 0 is printed as
cgroup inode id.  If the shrinker is not numa-aware, 0's are printed for
all nodes except the first one.

This commit gives debugfs entries simple numeric names, which are not very
convenient.  The following commit in the series will provide shrinkers
with more meaningful names.

[akpm@linux-foundation.org: remove WARN_ON_ONCE(), per Roman]
  Reported-by: syzbot+300d27c79fe6d4cbcc39@syzkaller.appspotmail.com
Link: https://lkml.kernel.org/r/20220601032227.4076670-3-roman.gushchin@linux.dev
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Acked-by: Muchun Song <songmuchun@bytedance.com>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hillf Danton <hdanton@sina.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-07-03 18:08:40 -07:00
Muchun Song
47010c040d mm: hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP* 
The word of "free" is not expressive enough to express the feature of
optimizing vmemmap pages associated with each HugeTLB, rename this keywork
to "optimize".  In this patch , cheanup configs to make code more
expressive.

Link: https://lkml.kernel.org/r/20220404074652.68024-4-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
 2022-04-28 23:16:15 -07:00
Christoph Hellwig
76cbbead25 mm: move the migrate_vma_* device migration code into its own file 
Split the code used to migrate to and from ZONE_DEVICE memory from
migrate.c into a new file.

Link: https://lkml.kernel.org/r/20220210072828.2930359-14-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: "Sierra Guiza, Alejandro (Alex)" <alex.sierra@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Ben Skeggs <bskeggs@redhat.com>
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Christian Knig <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Lyude Paul <lyude@redhat.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
 2022-03-03 12:47:33 -05:00
Christoph Hellwig
0a4ee51818 mm: remove cleancache 
Patch series "remove Xen tmem leftovers".

Since the removal of the Xen tmem driver in 2019, the cleancache hooks
are entirely unused, as are large parts of frontswap.  This series
against linux-next (with the folio changes included) removes
cleancaches, and cuts down frontswap to the bits actually used by zswap.

This patch (of 13):

The cleancache subsystem is unused since the removal of Xen tmem driver
in commit 814bbf49dc ("xen: remove tmem driver").

[akpm@linux-foundation.org: remove now-unreachable code]

Link: https://lkml.kernel.org/r/20211224062246.1258487-1-hch@lst.de
Link: https://lkml.kernel.org/r/20211224062246.1258487-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2022-01-22 08:33:38 +02:00
Linus Torvalds
f56caedaf9 Merge branch 'akpm' (patches from Andrew) 
Merge misc updates from Andrew Morton:
 "146 patches.

  Subsystems affected by this patch series: kthread, ia64, scripts,
  ntfs, squashfs, ocfs2, vfs, and mm (slab-generic, slab, kmemleak,
  dax, kasan, debug, pagecache, gup, shmem, frontswap, memremap,
  memcg, selftests, pagemap, dma, vmalloc, memory-failure, hugetlb,
  userfaultfd, vmscan, mempolicy, oom-kill, hugetlbfs, migration, thp,
  ksm, page-poison, percpu, rmap, zswap, zram, cleanups, hmm, and
  damon)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (146 commits)
  mm/damon: hide kernel pointer from tracepoint event
  mm/damon/vaddr: hide kernel pointer from damon_va_three_regions() failure log
  mm/damon/vaddr: use pr_debug() for damon_va_three_regions() failure logging
  mm/damon/dbgfs: remove an unnecessary variable
  mm/damon: move the implementation of damon_insert_region to damon.h
  mm/damon: add access checking for hugetlb pages
  Docs/admin-guide/mm/damon/usage: update for schemes statistics
  mm/damon/dbgfs: support all DAMOS stats
  Docs/admin-guide/mm/damon/reclaim: document statistics parameters
  mm/damon/reclaim: provide reclamation statistics
  mm/damon/schemes: account how many times quota limit has exceeded
  mm/damon/schemes: account scheme actions that successfully applied
  mm/damon: remove a mistakenly added comment for a future feature
  Docs/admin-guide/mm/damon/usage: update for kdamond_pid and (mk|rm)_contexts
  Docs/admin-guide/mm/damon/usage: mention tracepoint at the beginning
  Docs/admin-guide/mm/damon/usage: remove redundant information
  Docs/admin-guide/mm/damon/usage: update for scheme quotas and watermarks
  mm/damon: convert macro functions to static inline functions
  mm/damon: modify damon_rand() macro to static inline function
  mm/damon: move damon_rand() definition into damon.h
  ...
 2022-01-15 20:37:06 +02:00
Pasha Tatashin
df4e817b71 mm: page table check 
Check user page table entries at the time they are added and removed.

Allows to synchronously catch memory corruption issues related to double
mapping.

When a pte for an anonymous page is added into page table, we verify
that this pte does not already point to a file backed page, and vice
versa if this is a file backed page that is being added we verify that
this page does not have an anonymous mapping

We also enforce that read-only sharing for anonymous pages is allowed
(i.e.  cow after fork).  All other sharing must be for file pages.

Page table check allows to protect and debug cases where "struct page"
metadata became corrupted for some reason.  For example, when refcnt or
mapcount become invalid.

Link: https://lkml.kernel.org/r/20211221154650.1047963-4-pasha.tatashin@soleen.com
Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2022-01-15 16:30:28 +02:00
Marco Elver
d37d1fa015 mm, kcsan: Enable barrier instrumentation 
Some memory management calls imply memory barriers that are required to
avoid false positives. For example, without the correct instrumentation,
we could observe data races of the following variant:

                   T0           |           T1
        ------------------------+------------------------
                                |
         *a = 42;    ---+       |
         kfree(a);      |       |
                        |       | b = kmalloc(..); // b == a
          <reordered> <-+       | *b = 42;         // not a data race!
                                |

Therefore, instrument memory barriers in all allocator code currently
not being instrumented in a default build.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
 2021-12-09 16:42:28 -08:00
Matthew Wilcox (Oracle)
2f52578f9c mm/util: Add folio_mapping() and folio_file_mapping() 
These are the folio equivalent of page_mapping() and page_file_mapping().
Add an out-of-line page_mapping() wrapper around folio_mapping()
in order to prevent the page_folio() call from bloating every caller
of page_mapping().  Adjust page_file_mapping() and page_mapping_file()
to use folios internally.  Rename __page_file_mapping() to
swapcache_mapping() and change it to take a folio.

This ends up saving 122 bytes of text overall.  folio_mapping() is
45 bytes shorter than page_mapping() was, but the new page_mapping()
wrapper is 30 bytes.  The major reduction is a few bytes less in dozens
of nfs functions (which call page_file_mapping()).  Most of these appear
to be a slight change in gcc's register allocation decisions, which allow:

   48 8b 56 08         mov    0x8(%rsi),%rdx
   48 8d 42 ff         lea    -0x1(%rdx),%rax
   83 e2 01            and    $0x1,%edx
   48 0f 44 c6         cmove  %rsi,%rax

to become:

   48 8b 46 08         mov    0x8(%rsi),%rax
   48 8d 78 ff         lea    -0x1(%rax),%rdi
   a8 01               test   $0x1,%al
   48 0f 44 fe         cmove  %rsi,%rdi

for a reduction of a single byte.  Once the NFS client is converted to
use folios, this entire sequence will disappear.

Also add folio_mapping() documentation.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: David Howells <dhowells@redhat.com>
 2021-09-27 09:27:30 -04:00
SeongJae Park
2224d84854 mm: introduce Data Access MONitor (DAMON) 
Patch series "Introduce Data Access MONitor (DAMON)", v34.

Introduction
============

DAMON is a data access monitoring framework for the Linux kernel.  The
core mechanisms of DAMON called 'region based sampling' and 'adaptive
regions adjustment' (refer to 'mechanisms.rst' in the 11th patch of this
patchset for the detail) make it

- accurate (The monitored information is useful for DRAM level memory
  management.  It might not appropriate for Cache-level accuracy,
  though.),

- light-weight (The monitoring overhead is low enough to be applied
  online while making no impact on the performance of the target
  workloads.), and

- scalable (the upper-bound of the instrumentation overhead is
  controllable regardless of the size of target workloads.).

Using this framework, therefore, several memory management mechanisms such
as reclamation and THP can be optimized to aware real data access
patterns.  Experimental access pattern aware memory management
optimization works that incurring high instrumentation overhead will be
able to have another try.

Though DAMON is for kernel subsystems, it can be easily exposed to the
user space by writing a DAMON-wrapper kernel subsystem.  Then, user space
users who have some special workloads will be able to write personalized
tools or applications for deeper understanding and specialized
optimizations of their systems.

DAMON is also merged in two public Amazon Linux kernel trees that based on
v5.4.y[1] and v5.10.y[2].

[1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
[2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon

The userspace tool[1] is available, released under GPLv2, and actively
being maintained.  I am also planning to implement another basic user
interface in perf[2].  Also, the basic test suite for DAMON is available
under GPLv2[3].

[1] https://github.com/awslabs/damo
[2] https://lore.kernel.org/linux-mm/20210107120729.22328-1-sjpark@amazon.com/
[3] https://github.com/awslabs/damon-tests

Long-term Plan
--------------

DAMON is a part of a project called Data Access-aware Operating System
(DAOS).  As the name implies, I want to improve the performance and
efficiency of systems using fine-grained data access patterns.  The
optimizations are for both kernel and user spaces.  I will therefore
modify or create kernel subsystems, export some of those to user space and
implement user space library / tools.  Below shows the layers and
components for the project.

    ---------------------------------------------------------------------------
    Primitives:     PTE Accessed bit, PG_idle, rmap, (Intel CMT), ...
    Framework:      DAMON
    Features:       DAMOS, virtual addr, physical addr, ...
    Applications:   DAMON-debugfs, (DARC), ...
    ^^^^^^^^^^^^^^^^^^^^^^^    KERNEL SPACE    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    Raw Interface:  debugfs, (sysfs), (damonfs), tracepoints, (sys_damon), ...

    vvvvvvvvvvvvvvvvvvvvvvv    USER SPACE      vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    Library:        (libdamon), ...
    Tools:          DAMO, (perf), ...
    ---------------------------------------------------------------------------

The components in parentheses or marked as '...' are not implemented yet
but in the future plan.  IOW, those are the TODO tasks of DAOS project.
For more detail, please refer to the plans:
https://lore.kernel.org/linux-mm/20201202082731.24828-1-sjpark@amazon.com/

Evaluations
===========

We evaluated DAMON's overhead, monitoring quality and usefulness using 24
realistic workloads on my QEMU/KVM based virtual machine running a kernel
that v24 DAMON patchset is applied.

DAMON is lightweight.  It increases system memory usage by 0.39% and slows
target workloads down by 1.16%.

DAMON is accurate and useful for memory management optimizations.  An
experimental DAMON-based operation scheme for THP, namely 'ethp', removes
76.15% of THP memory overheads while preserving 51.25% of THP speedup.
Another experimental DAMON-based 'proactive reclamation' implementation,
'prcl', reduces 93.38% of residential sets and 23.63% of system memory
footprint while incurring only 1.22% runtime overhead in the best case
(parsec3/freqmine).

NOTE that the experimental THP optimization and proactive reclamation are
not for production but only for proof of concepts.

Please refer to the official document[1] or "Documentation/admin-guide/mm:
Add a document for DAMON" patch in this patchset for detailed evaluation
setup and results.

[1] https://damonitor.github.io/doc/html/latest-damon/admin-guide/mm/damon/eval.html

Real-world User Story
=====================

In summary, DAMON has used on production systems and proved its usefulness.

DAMON as a profiler
-------------------

We analyzed characteristics of a large scale production systems of our
customers using DAMON.  The systems utilize 70GB DRAM and 36 CPUs.  From
this, we were able to find interesting things below.

There were obviously different access pattern under idle workload and
active workload.  Under the idle workload, it accessed large memory
regions with low frequency, while the active workload accessed small
memory regions with high freuqnecy.

DAMON found a 7GB memory region that showing obviously high access
frequency under the active workload.  We believe this is the
performance-effective working set and need to be protected.

There was a 4KB memory region that showing highest access frequency under
not only active but also idle workloads.  We think this must be a hottest
code section like thing that should never be paged out.

For this analysis, DAMON used only 0.3-1% of single CPU time.  Because we
used recording-based analysis, it consumed about 3-12 MB of disk space per
20 minutes.  This is only small amount of disk space, but we can further
reduce the disk usage by using non-recording-based DAMON features.  I'd
like to argue that only DAMON can do such detailed analysis (finding 4KB
highest region in 70GB memory) with the light overhead.

DAMON as a system optimization tool
-----------------------------------

We also found below potential performance problems on the systems and made
DAMON-based solutions.

The system doesn't want to make the workload suffer from the page
reclamation and thus it utilizes enough DRAM but no swap device.  However,
we found the system is actively reclaiming file-backed pages, because the
system has intensive file IO.  The file IO turned out to be not
performance critical for the workload, but the customer wanted to ensure
performance critical file-backed pages like code section to not mistakenly
be evicted.

Using direct IO should or `mlock()` would be a straightforward solution,
but modifying the user space code is not easy for the customer.
Alternatively, we could use DAMON-based operation scheme[1].  By using it,
we can ask DAMON to track access frequency of each region and make
'process_madvise(MADV_WILLNEED)[2]' call for regions having specific size
and access frequency for a time interval.

We also found the system is having high number of TLB misses.  We tried
'always' THP enabled policy and it greatly reduced TLB misses, but the
page reclamation also been more frequent due to the THP internal
fragmentation caused memory bloat.  We could try another DAMON-based
operation scheme that applies 'MADV_HUGEPAGE' to memory regions having
>=2MB size and high access frequency, while applying 'MADV_NOHUGEPAGE' to
regions having <2MB size and low access frequency.

We do not own the systems so we only reported the analysis results and
possible optimization solutions to the customers.  The customers satisfied
about the analysis results and promised to try the optimization guides.

[1] https://lore.kernel.org/linux-mm/20201006123931.5847-1-sjpark@amazon.com/
[2] https://lore.kernel.org/linux-api/20200622192900.22757-4-minchan@kernel.org/

Comparison with Idle Page Tracking
==================================

Idle Page Tracking allows users to set and read idleness of pages using a
bitmap file which represents each page with each bit of the file.  One
recommended usage of it is working set size detection.  Users can do that
by

    1. find PFN of each page for workloads in interest,
    2. set all the pages as idle by doing writes to the bitmap file,
    3. wait until the workload accesses its working set, and
    4. read the idleness of the pages again and count pages became not idle.

NOTE: While Idle Page Tracking is for user space users, DAMON is primarily
designed for kernel subsystems though it can easily exposed to the user
space.  Hence, this section only assumes such user space use of DAMON.

For what use cases Idle Page Tracking would be better?
------------------------------------------------------

1. Flexible usecases other than hotness monitoring.

Because Idle Page Tracking allows users to control the primitive (Page
idleness) by themselves, Idle Page Tracking users can do anything they
want.  Meanwhile, DAMON is primarily designed to monitor the hotness of
each memory region.  For this, DAMON asks users to provide sampling
interval and aggregation interval.  For the reason, there could be some
use case that using Idle Page Tracking is simpler.

2. Physical memory monitoring.

Idle Page Tracking receives PFN range as input, so natively supports
physical memory monitoring.

DAMON is designed to be extensible for multiple address spaces and use
cases by implementing and using primitives for the given use case.
Therefore, by theory, DAMON has no limitation in the type of target
address space as long as primitives for the given address space exists.
However, the default primitives introduced by this patchset supports only
virtual address spaces.

Therefore, for physical memory monitoring, you should implement your own
primitives and use it, or simply use Idle Page Tracking.

Nonetheless, RFC patchsets[1] for the physical memory address space
primitives is already available.  It also supports user memory same to
Idle Page Tracking.

[1] https://lore.kernel.org/linux-mm/20200831104730.28970-1-sjpark@amazon.com/

For what use cases DAMON is better?
-----------------------------------

1. Hotness Monitoring.

Idle Page Tracking let users know only if a page frame is accessed or not.
For hotness check, the user should write more code and use more memory.
DAMON do that by itself.

2. Low Monitoring Overhead

DAMON receives user's monitoring request with one step and then provide
the results.  So, roughly speaking, DAMON require only O(1) user/kernel
context switches.

In case of Idle Page Tracking, however, because the interface receives
contiguous page frames, the number of user/kernel context switches
increases as the monitoring target becomes complex and huge.  As a result,
the context switch overhead could be not negligible.

Moreover, DAMON is born to handle with the monitoring overhead.  Because
the core mechanism is pure logical, Idle Page Tracking users might be able
to implement the mechanism on their own, but it would be time consuming
and the user/kernel context switching will still more frequent than that
of DAMON.  Also, the kernel subsystems cannot use the logic in this case.

3. Page granularity working set size detection.

Until v22 of this patchset, this was categorized as the thing Idle Page
Tracking could do better, because DAMON basically maintains additional
metadata for each of the monitoring target regions.  So, in the page
granularity working set size detection use case, DAMON would incur (number
of monitoring target pages * size of metadata) memory overhead.  Size of
the single metadata item is about 54 bytes, so assuming 4KB pages, about
1.3% of monitoring target pages will be additionally used.

All essential metadata for Idle Page Tracking are embedded in 'struct
page' and page table entries.  Therefore, in this use case, only one
counter variable for working set size accounting is required if Idle Page
Tracking is used.

There are more details to consider, but roughly speaking, this is true in
most cases.

However, the situation changed from v23.  Now DAMON supports arbitrary
types of monitoring targets, which don't use the metadata.  Using that,
DAMON can do the working set size detection with no additional space
overhead but less user-kernel context switch.  A first draft for the
implementation of monitoring primitives for this usage is available in a
DAMON development tree[1].  An RFC patchset for it based on this patchset
will also be available soon.

Since v24, the arbitrary type support is dropped from this patchset
because this patchset doesn't introduce real use of the type.  You can
still get it from the DAMON development tree[2], though.

[1] https://github.com/sjp38/linux/tree/damon/pgidle_hack
[2] https://github.com/sjp38/linux/tree/damon/master

4. More future usecases

While Idle Page Tracking has tight coupling with base primitives (PG_Idle
and page table Accessed bits), DAMON is designed to be extensible for many
use cases and address spaces.  If you need some special address type or
want to use special h/w access check primitives, you can write your own
primitives for that and configure DAMON to use those.  Therefore, if your
use case could be changed a lot in future, using DAMON could be better.

Can I use both Idle Page Tracking and DAMON?
--------------------------------------------

Yes, though using them concurrently for overlapping memory regions could
result in interference to each other.  Nevertheless, such use case would
be rare or makes no sense at all.  Even in the case, the noise would bot
be really significant.  So, you can choose whatever you want depending on
the characteristics of your use cases.

More Information
================

We prepared a showcase web site[1] that you can get more information.
There are

- the official documentations[2],
- the heatmap format dynamic access pattern of various realistic workloads for
  heap area[3], mmap()-ed area[4], and stack[5] area,
- the dynamic working set size distribution[6] and chronological working set
  size changes[7], and
- the latest performance test results[8].

[1] https://damonitor.github.io/_index
[2] https://damonitor.github.io/doc/html/latest-damon
[3] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.0.png.html
[4] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html
[5] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.2.png.html
[6] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html
[7] https://damonitor.github.io/test/result/visual/latest/rec.wss_time.png.html
[8] https://damonitor.github.io/test/result/perf/latest/html/index.html

Baseline and Complete Git Trees
===============================

The patches are based on the latest -mm tree, specifically
v5.14-rc1-mmots-2021-07-15-18-47 of https://github.com/hnaz/linux-mm.  You can
also clone the complete git tree:

    $ git clone git://github.com/sjp38/linux -b damon/patches/v34

The web is also available:
https://github.com/sjp38/linux/releases/tag/damon/patches/v34

Development Trees
-----------------

There are a couple of trees for entire DAMON patchset series and features
for future release.

- For latest release: https://github.com/sjp38/linux/tree/damon/master
- For next release: https://github.com/sjp38/linux/tree/damon/next

Long-term Support Trees
-----------------------

For people who want to test DAMON but using LTS kernels, there are another
couple of trees based on two latest LTS kernels respectively and
containing the 'damon/master' backports.

- For v5.4.y: https://github.com/sjp38/linux/tree/damon/for-v5.4.y
- For v5.10.y: https://github.com/sjp38/linux/tree/damon/for-v5.10.y

Amazon Linux Kernel Trees
-------------------------

DAMON is also merged in two public Amazon Linux kernel trees that based on
v5.4.y[1] and v5.10.y[2].

[1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
[2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon

Git Tree for Diff of Patches
============================

For easy review of diff between different versions of each patch, I
prepared a git tree containing all versions of the DAMON patchset series:
https://github.com/sjp38/damon-patches

You can clone it and use 'diff' for easy review of changes between
different versions of the patchset.  For example:

    $ git clone https://github.com/sjp38/damon-patches && cd damon-patches
    $ diff -u damon/v33 damon/v34

Sequence Of Patches
===================

First three patches implement the core logics of DAMON.  The 1st patch
introduces basic sampling based hotness monitoring for arbitrary types of
targets.  Following two patches implement the core mechanisms for control
of overhead and accuracy, namely regions based sampling (patch 2) and
adaptive regions adjustment (patch 3).

Now the essential parts of DAMON is complete, but it cannot work unless
someone provides monitoring primitives for a specific use case.  The
following two patches make it just work for virtual address spaces
monitoring.  The 4th patch makes 'PG_idle' can be used by DAMON and the
5th patch implements the virtual memory address space specific monitoring
primitives using page table Accessed bits and the 'PG_idle' page flag.

Now DAMON just works for virtual address space monitoring via the kernel
space api.  To let the user space users can use DAMON, following four
patches add interfaces for them.  The 6th patch adds a tracepoint for
monitoring results.  The 7th patch implements a DAMON application kernel
module, namely damon-dbgfs, that simply wraps DAMON and exposes DAMON
interface to the user space via the debugfs interface.  The 8th patch
further exports pid of monitoring thread (kdamond) to user space for
easier cpu usage accounting, and the 9th patch makes the debugfs interface
to support multiple contexts.

Three patches for maintainability follows.  The 10th patch adds
documentations for both the user space and the kernel space.  The 11th
patch provides unit tests (based on the kunit) while the 12th patch adds
user space tests (based on the kselftest).

Finally, the last patch (13th) updates the MAINTAINERS file.

This patch (of 13):

DAMON is a data access monitoring framework for the Linux kernel.  The
core mechanisms of DAMON make it

 - accurate (the monitoring output is useful enough for DRAM level
   performance-centric memory management; It might be inappropriate for
   CPU cache levels, though),
 - light-weight (the monitoring overhead is normally low enough to be
   applied online), and
 - scalable (the upper-bound of the overhead is in constant range
   regardless of the size of target workloads).

Using this framework, hence, we can easily write efficient kernel space
data access monitoring applications.  For example, the kernel's memory
management mechanisms can make advanced decisions using this.
Experimental data access aware optimization works that incurring high
access monitoring overhead could again be implemented on top of this.

Due to its simple and flexible interface, providing user space interface
would be also easy.  Then, user space users who have some special
workloads can write personalized applications for better understanding and
optimizations of their workloads and systems.

===

Nevertheless, this commit is defining and implementing only basic access
check part without the overhead-accuracy handling core logic.  The basic
access check is as below.

The output of DAMON says what memory regions are how frequently accessed
for a given duration.  The resolution of the access frequency is
controlled by setting ``sampling interval`` and ``aggregation interval``.
In detail, DAMON checks access to each page per ``sampling interval`` and
aggregates the results.  In other words, counts the number of the accesses
to each region.  After each ``aggregation interval`` passes, DAMON calls
callback functions that previously registered by users so that users can
read the aggregated results and then clears the results.  This can be
described in below simple pseudo-code::

    init()
    while monitoring_on:
        for page in monitoring_target:
            if accessed(page):
                nr_accesses[page] += 1
        if time() % aggregation_interval == 0:
            for callback in user_registered_callbacks:
                callback(monitoring_target, nr_accesses)
            for page in monitoring_target:
                nr_accesses[page] = 0
        if time() % update_interval == 0:
            update()
        sleep(sampling interval)

The target regions constructed at the beginning of the monitoring and
updated after each ``regions_update_interval``, because the target regions
could be dynamically changed (e.g., mmap() or memory hotplug).  The
monitoring overhead of this mechanism will arbitrarily increase as the
size of the target workload grows.

The basic monitoring primitives for actual access check and dynamic target
regions construction aren't in the core part of DAMON.  Instead, it allows
users to implement their own primitives that are optimized for their use
case and configure DAMON to use those.  In other words, users cannot use
current version of DAMON without some additional works.

Following commits will implement the core mechanisms for the
overhead-accuracy control and default primitives implementations.

Link: https://lkml.kernel.org/r/20210716081449.22187-1-sj38.park@gmail.com
Link: https://lkml.kernel.org/r/20210716081449.22187-2-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Marco Elver <elver@google.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
Christoph Hellwig
82a70ce042 mm: move ioremap_page_range to vmalloc.c 
Patch series "small ioremap cleanups".

The first patch moves a little code around the vmalloc/ioremap boundary
following a bigger move by Nick earlier.  The second enforces
non-executable mapping on ioremap just like we do for vmap.  No driver
currently uses executable mappings anyway, as they should.

This patch (of 2):

This keeps it together with the implementation, and to remove the
vmap_range wrapper.

Link: https://lkml.kernel.org/r/20210824091259.1324527-1-hch@lst.de
Link: https://lkml.kernel.org/r/20210824091259.1324527-2-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
Mike Rapoport
1507f51255 mm: introduce memfd_secret system call to create "secret" memory areas 
Introduce "memfd_secret" system call with the ability to create memory
areas visible only in the context of the owning process and not mapped not
only to other processes but in the kernel page tables as well.

The secretmem feature is off by default and the user must explicitly
enable it at the boot time.

Once secretmem is enabled, the user will be able to create a file
descriptor using the memfd_secret() system call.  The memory areas created
by mmap() calls from this file descriptor will be unmapped from the kernel
direct map and they will be only mapped in the page table of the processes
that have access to the file descriptor.

Secretmem is designed to provide the following protections:

* Enhanced protection (in conjunction with all the other in-kernel
  attack prevention systems) against ROP attacks.  Seceretmem makes
  "simple" ROP insufficient to perform exfiltration, which increases the
  required complexity of the attack.  Along with other protections like
  the kernel stack size limit and address space layout randomization which
  make finding gadgets is really hard, absence of any in-kernel primitive
  for accessing secret memory means the one gadget ROP attack can't work.
  Since the only way to access secret memory is to reconstruct the missing
  mapping entry, the attacker has to recover the physical page and insert
  a PTE pointing to it in the kernel and then retrieve the contents.  That
  takes at least three gadgets which is a level of difficulty beyond most
  standard attacks.

* Prevent cross-process secret userspace memory exposures.  Once the
  secret memory is allocated, the user can't accidentally pass it into the
  kernel to be transmitted somewhere.  The secreremem pages cannot be
  accessed via the direct map and they are disallowed in GUP.

* Harden against exploited kernel flaws.  In order to access secretmem,
  a kernel-side attack would need to either walk the page tables and
  create new ones, or spawn a new privileged uiserspace process to perform
  secrets exfiltration using ptrace.

The file descriptor based memory has several advantages over the
"traditional" mm interfaces, such as mlock(), mprotect(), madvise().  File
descriptor approach allows explicit and controlled sharing of the memory
areas, it allows to seal the operations.  Besides, file descriptor based
memory paves the way for VMMs to remove the secret memory range from the
userspace hipervisor process, for instance QEMU.  Andy Lutomirski says:

  "Getting fd-backed memory into a guest will take some possibly major
  work in the kernel, but getting vma-backed memory into a guest without
  mapping it in the host user address space seems much, much worse."

memfd_secret() is made a dedicated system call rather than an extension to
memfd_create() because it's purpose is to allow the user to create more
secure memory mappings rather than to simply allow file based access to
the memory.  Nowadays a new system call cost is negligible while it is way
simpler for userspace to deal with a clear-cut system calls than with a
multiplexer or an overloaded syscall.  Moreover, the initial
implementation of memfd_secret() is completely distinct from
memfd_create() so there is no much sense in overloading memfd_create() to
begin with.  If there will be a need for code sharing between these
implementation it can be easily achieved without a need to adjust user
visible APIs.

The secret memory remains accessible in the process context using uaccess
primitives, but it is not exposed to the kernel otherwise; secret memory
areas are removed from the direct map and functions in the
follow_page()/get_user_page() family will refuse to return a page that
belongs to the secret memory area.

Once there will be a use case that will require exposing secretmem to the
kernel it will be an opt-in request in the system call flags so that user
would have to decide what data can be exposed to the kernel.

Removing of the pages from the direct map may cause its fragmentation on
architectures that use large pages to map the physical memory which
affects the system performance.  However, the original Kconfig text for
CONFIG_DIRECT_GBPAGES said that gigabyte pages in the direct map "...  can
improve the kernel's performance a tiny bit ..." (commit 00d1c5e057
("x86: add gbpages switches")) and the recent report [1] showed that "...
although 1G mappings are a good default choice, there is no compelling
evidence that it must be the only choice".  Hence, it is sufficient to
have secretmem disabled by default with the ability of a system
administrator to enable it at boot time.

Pages in the secretmem regions are unevictable and unmovable to avoid
accidental exposure of the sensitive data via swap or during page
migration.

Since the secretmem mappings are locked in memory they cannot exceed
RLIMIT_MEMLOCK.  Since these mappings are already locked independently
from mlock(), an attempt to mlock()/munlock() secretmem range would fail
and mlockall()/munlockall() will ignore secretmem mappings.

However, unlike mlock()ed memory, secretmem currently behaves more like
long-term GUP: secretmem mappings are unmovable mappings directly consumed
by user space.  With default limits, there is no excessive use of
secretmem and it poses no real problem in combination with
ZONE_MOVABLE/CMA, but in the future this should be addressed to allow
balanced use of large amounts of secretmem along with ZONE_MOVABLE/CMA.

A page that was a part of the secret memory area is cleared when it is
freed to ensure the data is not exposed to the next user of that page.

The following example demonstrates creation of a secret mapping (error
handling is omitted):

	fd = memfd_secret(0);
	ftruncate(fd, MAP_SIZE);
	ptr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
		   MAP_SHARED, fd, 0);

[1] https://lore.kernel.org/linux-mm/213b4567-46ce-f116-9cdf-bbd0c884eb3c@linux.intel.com/

[akpm@linux-foundation.org: suppress Kconfig whine]

Link: https://lkml.kernel.org/r/20210518072034.31572-5-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Hagen Paul Pfeifer <hagen@jauu.net>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tycho Andersen <tycho@tycho.ws>
Cc: Will Deacon <will@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-07-08 11:48:21 -07:00
Muchun Song
f41f2ed43c mm: hugetlb: free the vmemmap pages associated with each HugeTLB page 
Every HugeTLB has more than one struct page structure.  We __know__ that
we only use the first 4 (__NR_USED_SUBPAGE) struct page structures to
store metadata associated with each HugeTLB.

There are a lot of struct page structures associated with each HugeTLB
page.  For tail pages, the value of compound_head is the same.  So we can
reuse first page of tail page structures.  We map the virtual addresses of
the remaining pages of tail page structures to the first tail page struct,
and then free these page frames.  Therefore, we need to reserve two pages
as vmemmap areas.

When we allocate a HugeTLB page from the buddy, we can free some vmemmap
pages associated with each HugeTLB page.  It is more appropriate to do it
in the prep_new_huge_page().

The free_vmemmap_pages_per_hpage(), which indicates how many vmemmap pages
associated with a HugeTLB page can be freed, returns zero for now, which
means the feature is disabled.  We will enable it once all the
infrastructure is there.

[willy@infradead.org: fix documentation warning]
  Link: https://lkml.kernel.org/r/20210615200242.1716568-5-willy@infradead.org

Link: https://lkml.kernel.org/r/20210510030027.56044-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Tested-by: Chen Huang <chenhuang5@huawei.com>
Tested-by: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-06-30 20:47:25 -07:00
Muchun Song
426e5c429d mm: memory_hotplug: factor out bootmem core functions to bootmem_info.c 
Patch series "Free some vmemmap pages of HugeTLB page", v23.

This patch series will free some vmemmap pages(struct page structures)
associated with each HugeTLB page when preallocated to save memory.

In order to reduce the difficulty of the first version of code review.  In
this version, we disable PMD/huge page mapping of vmemmap if this feature
was enabled.  This acutely eliminates a bunch of the complex code doing
page table manipulation.  When this patch series is solid, we cam add the
code of vmemmap page table manipulation in the future.

The struct page structures (page structs) are used to describe a physical
page frame.  By default, there is an one-to-one mapping from a page frame
to it's corresponding page struct.

The HugeTLB pages consist of multiple base page size pages and is
supported by many architectures.  See hugetlbpage.rst in the Documentation
directory for more details.  On the x86 architecture, HugeTLB pages of
size 2MB and 1GB are currently supported.  Since the base page size on x86
is 4KB, a 2MB HugeTLB page consists of 512 base pages and a 1GB HugeTLB
page consists of 4096 base pages.  For each base page, there is a
corresponding page struct.

Within the HugeTLB subsystem, only the first 4 page structs are used to
contain unique information about a HugeTLB page.  HUGETLB_CGROUP_MIN_ORDER
provides this upper limit.  The only 'useful' information in the remaining
page structs is the compound_head field, and this field is the same for
all tail pages.

By removing redundant page structs for HugeTLB pages, memory can returned
to the buddy allocator for other uses.

When the system boot up, every 2M HugeTLB has 512 struct page structs which
size is 8 pages(sizeof(struct page) * 512 / PAGE_SIZE).

    HugeTLB                  struct pages(8 pages)         page frame(8 pages)
 +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
 |           |                     |     0     | -------------> |     0     |
 |           |                     +-----------+                +-----------+
 |           |                     |     1     | -------------> |     1     |
 |           |                     +-----------+                +-----------+
 |           |                     |     2     | -------------> |     2     |
 |           |                     +-----------+                +-----------+
 |           |                     |     3     | -------------> |     3     |
 |           |                     +-----------+                +-----------+
 |           |                     |     4     | -------------> |     4     |
 |    2MB    |                     +-----------+                +-----------+
 |           |                     |     5     | -------------> |     5     |
 |           |                     +-----------+                +-----------+
 |           |                     |     6     | -------------> |     6     |
 |           |                     +-----------+                +-----------+
 |           |                     |     7     | -------------> |     7     |
 |           |                     +-----------+                +-----------+
 |           |
 |           |
 |           |
 +-----------+

The value of page->compound_head is the same for all tail pages.  The
first page of page structs (page 0) associated with the HugeTLB page
contains the 4 page structs necessary to describe the HugeTLB.  The only
use of the remaining pages of page structs (page 1 to page 7) is to point
to page->compound_head.  Therefore, we can remap pages 2 to 7 to page 1.
Only 2 pages of page structs will be used for each HugeTLB page.  This
will allow us to free the remaining 6 pages to the buddy allocator.

Here is how things look after remapping.

    HugeTLB                  struct pages(8 pages)         page frame(8 pages)
 +-----------+ ---virt_to_page---> +-----------+   mapping to   +-----------+
 |           |                     |     0     | -------------> |     0     |
 |           |                     +-----------+                +-----------+
 |           |                     |     1     | -------------> |     1     |
 |           |                     +-----------+                +-----------+
 |           |                     |     2     | ----------------^ ^ ^ ^ ^ ^
 |           |                     +-----------+                   | | | | |
 |           |                     |     3     | ------------------+ | | | |
 |           |                     +-----------+                     | | | |
 |           |                     |     4     | --------------------+ | | |
 |    2MB    |                     +-----------+                       | | |
 |           |                     |     5     | ----------------------+ | |
 |           |                     +-----------+                         | |
 |           |                     |     6     | ------------------------+ |
 |           |                     +-----------+                           |
 |           |                     |     7     | --------------------------+
 |           |                     +-----------+
 |           |
 |           |
 |           |
 +-----------+

When a HugeTLB is freed to the buddy system, we should allocate 6 pages
for vmemmap pages and restore the previous mapping relationship.

Apart from 2MB HugeTLB page, we also have 1GB HugeTLB page.  It is similar
to the 2MB HugeTLB page.  We also can use this approach to free the
vmemmap pages.

In this case, for the 1GB HugeTLB page, we can save 4094 pages.  This is a
very substantial gain.  On our server, run some SPDK/QEMU applications
which will use 1024GB HugeTLB page.  With this feature enabled, we can
save ~16GB (1G hugepage)/~12GB (2MB hugepage) memory.

Because there are vmemmap page tables reconstruction on the
freeing/allocating path, it increases some overhead.  Here are some
overhead analysis.

1) Allocating 10240 2MB HugeTLB pages.

   a) With this patch series applied:
   # time echo 10240 > /proc/sys/vm/nr_hugepages

   real     0m0.166s
   user     0m0.000s
   sys      0m0.166s

   # bpftrace -e 'kprobe:alloc_fresh_huge_page { @start[tid] = nsecs; }
     kretprobe:alloc_fresh_huge_page /@start[tid]/ { @latency = hist(nsecs -
     @start[tid]); delete(@start[tid]); }'
   Attaching 2 probes...

   @latency:
   [8K, 16K)           5476 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
   [16K, 32K)          4760 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@       |
   [32K, 64K)             4 |                                                    |

   b) Without this patch series:
   # time echo 10240 > /proc/sys/vm/nr_hugepages

   real     0m0.067s
   user     0m0.000s
   sys      0m0.067s

   # bpftrace -e 'kprobe:alloc_fresh_huge_page { @start[tid] = nsecs; }
     kretprobe:alloc_fresh_huge_page /@start[tid]/ { @latency = hist(nsecs -
     @start[tid]); delete(@start[tid]); }'
   Attaching 2 probes...

   @latency:
   [4K, 8K)           10147 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
   [8K, 16K)             93 |                                                    |

   Summarize: this feature is about ~2x slower than before.

2) Freeing 10240 2MB HugeTLB pages.

   a) With this patch series applied:
   # time echo 0 > /proc/sys/vm/nr_hugepages

   real     0m0.213s
   user     0m0.000s
   sys      0m0.213s

   # bpftrace -e 'kprobe:free_pool_huge_page { @start[tid] = nsecs; }
     kretprobe:free_pool_huge_page /@start[tid]/ { @latency = hist(nsecs -
     @start[tid]); delete(@start[tid]); }'
   Attaching 2 probes...

   @latency:
   [8K, 16K)              6 |                                                    |
   [16K, 32K)         10227 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
   [32K, 64K)             7 |                                                    |

   b) Without this patch series:
   # time echo 0 > /proc/sys/vm/nr_hugepages

   real     0m0.081s
   user     0m0.000s
   sys      0m0.081s

   # bpftrace -e 'kprobe:free_pool_huge_page { @start[tid] = nsecs; }
     kretprobe:free_pool_huge_page /@start[tid]/ { @latency = hist(nsecs -
     @start[tid]); delete(@start[tid]); }'
   Attaching 2 probes...

   @latency:
   [4K, 8K)            6805 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
   [8K, 16K)           3427 |@@@@@@@@@@@@@@@@@@@@@@@@@@                          |
   [16K, 32K)             8 |                                                    |

   Summary: The overhead of __free_hugepage is about ~2-3x slower than before.

Although the overhead has increased, the overhead is not significant.
Like Mike said, "However, remember that the majority of use cases create
HugeTLB pages at or shortly after boot time and add them to the pool.  So,
additional overhead is at pool creation time.  There is no change to
'normal run time' operations of getting a page from or returning a page to
the pool (think page fault/unmap)".

Despite the overhead and in addition to the memory gains from this series.
The following data is obtained by Joao Martins.  Very thanks to his
effort.

There's an additional benefit which is page (un)pinners will see an improvement
and Joao presumes because there are fewer memmap pages and thus the tail/head
pages are staying in cache more often.

Out of the box Joao saw (when comparing linux-next against linux-next +
this series) with gup_test and pinning a 16G HugeTLB file (with 1G pages):

	get_user_pages(): ~32k -> ~9k
	unpin_user_pages(): ~75k -> ~70k

Usually any tight loop fetching compound_head(), or reading tail pages
data (e.g.  compound_head) benefit a lot.  There's some unpinning
inefficiencies Joao was fixing[2], but with that in added it shows even
more:

	unpin_user_pages(): ~27k -> ~3.8k

[1] https://lore.kernel.org/linux-mm/20210409205254.242291-1-mike.kravetz@oracle.com/
[2] https://lore.kernel.org/linux-mm/20210204202500.26474-1-joao.m.martins@oracle.com/

This patch (of 9):

Move bootmem info registration common API to individual bootmem_info.c.
And we will use {get,put}_page_bootmem() to initialize the page for the
vmemmap pages or free the vmemmap pages to buddy in the later patch.  So
move them out of CONFIG_MEMORY_HOTPLUG_SPARSE.  This is just code movement
without any functional change.

Link: https://lkml.kernel.org/r/20210510030027.56044-1-songmuchun@bytedance.com
Link: https://lkml.kernel.org/r/20210510030027.56044-2-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Tested-by: Chen Huang <chenhuang5@huawei.com>
Tested-by: Bodeddula Balasubramaniam <bodeddub@amazon.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Oliver Neukum <oneukum@suse.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Mina Almasry <almasrymina@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: Joao Martins <joao.m.martins@oracle.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-06-30 20:47:25 -07:00
Oscar Salvador
e3a9d9fcc3 mm,memory_hotplug: add kernel boot option to enable memmap_on_memory 
Self stored memmap leads to a sparse memory situation which is
unsuitable for workloads that requires large contiguous memory chunks,
so make this an opt-in which needs to be explicitly enabled.

To control this, let memory_hotplug have its own memory space, as
suggested by David, so we can add memory_hotplug.memmap_on_memory
parameter.

Link: https://lkml.kernel.org/r/20210421102701.25051-7-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-05-05 11:27:27 -07:00
Minchan Kim
43ca106fa8 mm: cma: support sysfs 
Since CMA is getting used more widely, it's more important to keep
monitoring CMA statistics for system health since it's directly related to
user experience.

This patch introduces sysfs statistics for CMA, in order to provide some
basic monitoring of the CMA allocator.

 * the number of CMA page successful allocations
 * the number of CMA page allocation failures

These two values allow the user to calcuate the allocation
failure rate for each CMA area.

e.g.)
  /sys/kernel/mm/cma/WIFI/alloc_pages_[success|fail]
  /sys/kernel/mm/cma/SENSOR/alloc_pages_[success|fail]
  /sys/kernel/mm/cma/BLUETOOTH/alloc_pages_[success|fail]

The cma_stat was intentionally allocated by dynamic allocation
to harmonize with kobject lifetime management.
https://lore.kernel.org/linux-mm/YCOAmXqt6dZkCQYs@kroah.com/

Link: https://lkml.kernel.org/r/20210324230759.2213957-1-minchan@kernel.org
Link: https://lore.kernel.org/linux-mm/20210316100433.17665-1-colin.king@canonical.com/
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>

Tested-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: John Dias <joaodias@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-05-05 11:27:24 -07:00
Christoph Hellwig
1fbaf8fc12 mm: add a io_mapping_map_user helper 
Add a helper that calls remap_pfn_range for an struct io_mapping, relying
on the pgprot pre-validation done when creating the mapping instead of
doing it at runtime.

Link: https://lkml.kernel.org/r/20210326055505.1424432-3-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-04-30 11:20:39 -07:00
Alexander Potapenko
0ce20dd840 mm: add Kernel Electric-Fence infrastructure 
Patch series "KFENCE: A low-overhead sampling-based memory safety error detector", v7.

This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a
low-overhead sampling-based memory safety error detector of heap
use-after-free, invalid-free, and out-of-bounds access errors.  This
series enables KFENCE for the x86 and arm64 architectures, and adds
KFENCE hooks to the SLAB and SLUB allocators.

KFENCE is designed to be enabled in production kernels, and has near
zero performance overhead. Compared to KASAN, KFENCE trades performance
for precision. The main motivation behind KFENCE's design, is that with
enough total uptime KFENCE will detect bugs in code paths not typically
exercised by non-production test workloads. One way to quickly achieve a
large enough total uptime is when the tool is deployed across a large
fleet of machines.

KFENCE objects each reside on a dedicated page, at either the left or
right page boundaries. The pages to the left and right of the object
page are "guard pages", whose attributes are changed to a protected
state, and cause page faults on any attempted access to them. Such page
faults are then intercepted by KFENCE, which handles the fault
gracefully by reporting a memory access error.

Guarded allocations are set up based on a sample interval (can be set
via kfence.sample_interval). After expiration of the sample interval,
the next allocation through the main allocator (SLAB or SLUB) returns a
guarded allocation from the KFENCE object pool. At this point, the timer
is reset, and the next allocation is set up after the expiration of the
interval.

To enable/disable a KFENCE allocation through the main allocator's
fast-path without overhead, KFENCE relies on static branches via the
static keys infrastructure. The static branch is toggled to redirect the
allocation to KFENCE.

The KFENCE memory pool is of fixed size, and if the pool is exhausted no
further KFENCE allocations occur. The default config is conservative
with only 255 objects, resulting in a pool size of 2 MiB (with 4 KiB
pages).

We have verified by running synthetic benchmarks (sysbench I/O,
hackbench) and production server-workload benchmarks that a kernel with
KFENCE (using sample intervals 100-500ms) is performance-neutral
compared to a non-KFENCE baseline kernel.

KFENCE is inspired by GWP-ASan [1], a userspace tool with similar
properties. The name "KFENCE" is a homage to the Electric Fence Malloc
Debugger [2].

For more details, see Documentation/dev-tools/kfence.rst added in the
series -- also viewable here:

	https://raw.githubusercontent.com/google/kasan/kfence/Documentation/dev-tools/kfence.rst

[1] http://llvm.org/docs/GwpAsan.html
[2] https://linux.die.net/man/3/efence

This patch (of 9):

This adds the Kernel Electric-Fence (KFENCE) infrastructure. KFENCE is a
low-overhead sampling-based memory safety error detector of heap
use-after-free, invalid-free, and out-of-bounds access errors.

KFENCE is designed to be enabled in production kernels, and has near
zero performance overhead. Compared to KASAN, KFENCE trades performance
for precision. The main motivation behind KFENCE's design, is that with
enough total uptime KFENCE will detect bugs in code paths not typically
exercised by non-production test workloads. One way to quickly achieve a
large enough total uptime is when the tool is deployed across a large
fleet of machines.

KFENCE objects each reside on a dedicated page, at either the left or
right page boundaries. The pages to the left and right of the object
page are "guard pages", whose attributes are changed to a protected
state, and cause page faults on any attempted access to them. Such page
faults are then intercepted by KFENCE, which handles the fault
gracefully by reporting a memory access error. To detect out-of-bounds
writes to memory within the object's page itself, KFENCE also uses
pattern-based redzones. The following figure illustrates the page
layout:

  ---+-----------+-----------+-----------+-----------+-----------+---
     | xxxxxxxxx | O :       | xxxxxxxxx |       : O | xxxxxxxxx |
     | xxxxxxxxx | B :       | xxxxxxxxx |       : B | xxxxxxxxx |
     | x GUARD x | J : RED-  | x GUARD x | RED-  : J | x GUARD x |
     | xxxxxxxxx | E :  ZONE | xxxxxxxxx |  ZONE : E | xxxxxxxxx |
     | xxxxxxxxx | C :       | xxxxxxxxx |       : C | xxxxxxxxx |
     | xxxxxxxxx | T :       | xxxxxxxxx |       : T | xxxxxxxxx |
  ---+-----------+-----------+-----------+-----------+-----------+---

Guarded allocations are set up based on a sample interval (can be set
via kfence.sample_interval). After expiration of the sample interval, a
guarded allocation from the KFENCE object pool is returned to the main
allocator (SLAB or SLUB). At this point, the timer is reset, and the
next allocation is set up after the expiration of the interval.

To enable/disable a KFENCE allocation through the main allocator's
fast-path without overhead, KFENCE relies on static branches via the
static keys infrastructure. The static branch is toggled to redirect the
allocation to KFENCE. To date, we have verified by running synthetic
benchmarks (sysbench I/O, hackbench) that a kernel compiled with KFENCE
is performance-neutral compared to the non-KFENCE baseline.

For more details, see Documentation/dev-tools/kfence.rst (added later in
the series).

[elver@google.com: fix parameter description for kfence_object_start()]
  Link: https://lkml.kernel.org/r/20201106092149.GA2851373@elver.google.com
[elver@google.com: avoid stalling work queue task without allocations]
  Link: https://lkml.kernel.org/r/CADYN=9J0DQhizAGB0-jz4HOBBh+05kMBXb4c0cXMS7Qi5NAJiw@mail.gmail.com
  Link: https://lkml.kernel.org/r/20201110135320.3309507-1-elver@google.com
[elver@google.com: fix potential deadlock due to wake_up()]
  Link: https://lkml.kernel.org/r/000000000000c0645805b7f982e4@google.com
  Link: https://lkml.kernel.org/r/20210104130749.1768991-1-elver@google.com
[elver@google.com: add option to use KFENCE without static keys]
  Link: https://lkml.kernel.org/r/20210111091544.3287013-1-elver@google.com
[elver@google.com: add missing copyright and description headers]
  Link: https://lkml.kernel.org/r/20210118092159.145934-1-elver@google.com

Link: https://lkml.kernel.org/r/20201103175841.3495947-2-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: SeongJae Park <sjpark@amazon.de>
Co-developed-by: Marco Elver <elver@google.com>
Reviewed-by: Jann Horn <jannh@google.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christopher Lameter <cl@linux.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Joern Engel <joern@purestorage.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-02-26 09:41:02 -08:00
Daniel Vetter
eb83b8e3e6 media: videobuf2: Move frame_vector into media subsystem 
It's the only user. This also garbage collects the CONFIG_FRAME_VECTOR
symbol from all over the tree (well just one place, somehow omap media
driver still had this in its Kconfig, despite not using it).

Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Acked-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Tomasz Figa <tfiga@chromium.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20201127164131.2244124-7-daniel.vetter@ffwll.ch
 2021-01-12 14:15:31 +01:00
Axel Rasmussen
2b5067a814 mm: mmap_lock: add tracepoints around lock acquisition 
The goal of these tracepoints is to be able to debug lock contention
issues.  This lock is acquired on most (all?) mmap / munmap / page fault
operations, so a multi-threaded process which does a lot of these can
experience significant contention.

We trace just before we start acquisition, when the acquisition returns
(whether it succeeded or not), and when the lock is released (or
downgraded).  The events are broken out by lock type (read / write).

The events are also broken out by memcg path.  For container-based
workloads, users often think of several processes in a memcg as a single
logical "task", so collecting statistics at this level is useful.

The end goal is to get latency information.  This isn't directly included
in the trace events.  Instead, users are expected to compute the time
between "start locking" and "acquire returned", using e.g.  synthetic
events or BPF.  The benefit we get from this is simpler code.

Because we use tracepoint_enabled() to decide whether or not to trace,
this patch has effectively no overhead unless tracepoints are enabled at
runtime.  If tracepoints are enabled, there is a performance impact, but
how much depends on exactly what e.g.  the BPF program does.

[axelrasmussen@google.com: fix use-after-free race and css ref leak in tracepoints]
  Link: https://lkml.kernel.org/r/20201130233504.3725241-1-axelrasmussen@google.com
[axelrasmussen@google.com: v3]
  Link: https://lkml.kernel.org/r/20201207213358.573750-1-axelrasmussen@google.com
[rostedt@goodmis.org: in-depth examples of tracepoint_enabled() usage, and per-cpu-per-context buffer design]

Link: https://lkml.kernel.org/r/20201105211739.568279-2-axelrasmussen@google.com
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-12-15 12:13:41 -08:00
John Hubbard
9c84f22926 mm/gup_benchmark: rename to mm/gup_test 
Patch series "selftests/vm: gup_test, hmm-tests, assorted improvements", v3.

Summary: This series provides two main things, and a number of smaller
supporting goodies.  The two main points are:

1) Add a new sub-test to gup_test, which in turn is a renamed version
   of gup_benchmark.  This sub-test allows nicer testing of dump_pages(),
   at least on user-space pages.

   For quite a while, I was doing a quick hack to gup_test.c whenever I
   wanted to try out changes to dump_page().  Then Matthew Wilcox asked me
   what I meant when I said "I used my dump_page() unit test", and I
   realized that it might be nice to check in a polished up version of
   that.

   Details about how it works and how to use it are in the commit
   description for patch #6 ("selftests/vm: gup_test: introduce the
   dump_pages() sub-test").

2) Fixes a limitation of hmm-tests: these tests are incredibly useful,
   but only if people actually build and run them.  And it turns out that
   libhugetlbfs is a little too effective at throwing a wrench in the
   works, there.  So I've added a little configuration check that removes
   just two of the 21 hmm-tests, if libhugetlbfs is not available.

   Further details in the commit description of patch #8
   ("selftests/vm: hmm-tests: remove the libhugetlbfs dependency").

Other smaller things that this series does:

a) Remove code duplication by creating gup_test.h.

b) Clear up the sub-test organization, and their invocation within
   run_vmtests.sh.

c) Other minor assorted improvements.

[1] v2 is here:
https://lore.kernel.org/linux-doc/20200929212747.251804-1-jhubbard@nvidia.com/

[2] https://lore.kernel.org/r/CAHk-=wgh-TMPHLY3jueHX7Y2fWh3D+nMBqVS__AZm6-oorquWA@mail.gmail.com

This patch (of 9):

Rename nearly every "gup_benchmark" reference and file name to "gup_test".
The one exception is for the actual gup benchmark test itself.

The current code already does a *little* bit more than benchmarking, and
definitely covers more than get_user_pages_fast().  More importantly,
however, subsequent patches are about to add some functionality that is
non-benchmark related.

Closely related changes:

* Kconfig: in addition to renaming the options from GUP_BENCHMARK to
  GUP_TEST, update the help text to reflect that it's no longer a
  benchmark-only test.

Link: https://lkml.kernel.org/r/20201026064021.3545418-1-jhubbard@nvidia.com
Link: https://lkml.kernel.org/r/20201026064021.3545418-2-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-12-15 12:13:38 -08:00
Hui Su
1abbef4f51 mm,kmemleak-test.c: move kmemleak-test.c to samples dir 
kmemleak-test.c is just a kmemleak test module, which also can not be used
as a built-in kernel module.  Thus, i think it may should not be in mm
dir, and move the kmemleak-test.c to samples/kmemleak/kmemleak-test.c.
Fix the spelling of built-in by the way.

Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rob Herring <robh@kernel.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Divya Indi <divya.indi@oracle.com>
Cc: Tomas Winkler <tomas.winkler@intel.com>
Cc: David Howells <dhowells@redhat.com>
Link: https://lkml.kernel.org/r/20200925183729.GA172837@rlk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-10-13 18:38:27 -07:00
Mike Rapoport
ab05eabfa1 mm: move lib/ioremap.c to mm/ 
The functionality in lib/ioremap.c deals with pagetables, vmalloc and
caches, so it naturally belongs to mm/ Moving it there will also allow
declaring p?d_alloc_track functions in an header file inside mm/ rather
than having those declarations in include/linux/mm.h

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-8-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2020-08-07 11:33:26 -07:00
Linus Torvalds
b791d1bdf9 The Kernel Concurrency Sanitizer (KCSAN) 
KCSAN is a dynamic race detector, which relies on compile-time
 instrumentation, and uses a watchpoint-based sampling approach to detect
 races.
 
 The feature was under development for quite some time and has already found
 legitimate bugs.
 
 Unfortunately it comes with a limitation, which was only understood late in
 the development cycle:
 
   It requires an up to date CLANG-11 compiler
 
 CLANG-11 is not yet released (scheduled for June), but it's the only
 compiler today which handles the kernel requirements and especially the
 annotations of functions to exclude them from KCSAN instrumentation
 correctly.
 
 These annotations really need to work so that low level entry code and
 especially int3 text poke handling can be completely isolated.
 
 A detailed discussion of the requirements and compiler issues can be found
 here:
 
   https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/
 
 We came to the conclusion that trying to work around compiler limitations
 and bugs again would end up in a major trainwreck, so requiring a working
 compiler seemed to be the best choice.
 
 For Continous Integration purposes the compiler restriction is manageable
 and that's where most xxSAN reports come from.
 
 For a change this limitation might make GCC people actually look at their
 bugs. Some issues with CSAN in GCC are 7 years old and one has been 'fixed'
 3 years ago with a half baken solution which 'solved' the reported issue
 but not the underlying problem.
 
 The KCSAN developers also ponder to use a GCC plugin to become independent,
 but that's not something which will show up in a few days.
 
 Blocking KCSAN until wide spread compiler support is available is not a
 really good alternative because the continuous growth of lockless
 optimizations in the kernel demands proper tooling support.
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Merge tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull the Kernel Concurrency Sanitizer from Thomas Gleixner:
 "The Kernel Concurrency Sanitizer (KCSAN) is a dynamic race detector,
  which relies on compile-time instrumentation, and uses a
  watchpoint-based sampling approach to detect races.

  The feature was under development for quite some time and has already
  found legitimate bugs.

  Unfortunately it comes with a limitation, which was only understood
  late in the development cycle:

     It requires an up to date CLANG-11 compiler

  CLANG-11 is not yet released (scheduled for June), but it's the only
  compiler today which handles the kernel requirements and especially
  the annotations of functions to exclude them from KCSAN
  instrumentation correctly.

  These annotations really need to work so that low level entry code and
  especially int3 text poke handling can be completely isolated.

  A detailed discussion of the requirements and compiler issues can be
  found here:

    https://lore.kernel.org/lkml/CANpmjNMTsY_8241bS7=XAfqvZHFLrVEkv_uM4aDUWE_kh3Rvbw@mail.gmail.com/

  We came to the conclusion that trying to work around compiler
  limitations and bugs again would end up in a major trainwreck, so
  requiring a working compiler seemed to be the best choice.

  For Continous Integration purposes the compiler restriction is
  manageable and that's where most xxSAN reports come from.

  For a change this limitation might make GCC people actually look at
  their bugs. Some issues with CSAN in GCC are 7 years old and one has
  been 'fixed' 3 years ago with a half baken solution which 'solved' the
  reported issue but not the underlying problem.

  The KCSAN developers also ponder to use a GCC plugin to become
  independent, but that's not something which will show up in a few
  days.

  Blocking KCSAN until wide spread compiler support is available is not
  a really good alternative because the continuous growth of lockless
  optimizations in the kernel demands proper tooling support"

* tag 'locking-kcsan-2020-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (76 commits)
  compiler_types.h, kasan: Use __SANITIZE_ADDRESS__ instead of CONFIG_KASAN to decide inlining
  compiler.h: Move function attributes to compiler_types.h
  compiler.h: Avoid nested statement expression in data_race()
  compiler.h: Remove data_race() and unnecessary checks from {READ,WRITE}_ONCE()
  kcsan: Update Documentation to change supported compilers
  kcsan: Remove 'noinline' from __no_kcsan_or_inline
  kcsan: Pass option tsan-instrument-read-before-write to Clang
  kcsan: Support distinguishing volatile accesses
  kcsan: Restrict supported compilers
  kcsan: Avoid inserting __tsan_func_entry/exit if possible
  ubsan, kcsan: Don't combine sanitizer with kcov on clang
  objtool, kcsan: Add kcsan_disable_current() and kcsan_enable_current_nowarn()
  kcsan: Add __kcsan_{enable,disable}_current() variants
  checkpatch: Warn about data_race() without comment
  kcsan: Use GFP_ATOMIC under spin lock
  Improve KCSAN documentation a bit
  kcsan: Make reporting aware of KCSAN tests
  kcsan: Fix function matching in report
  kcsan: Change data_race() to no longer require marking racing accesses
  kcsan: Move kcsan_{disable,enable}_current() to kcsan-checks.h
  ...
 2020-06-11 18:55:43 -07:00