linux/mm
Waiman Long c77c0a8ac4 mm/hugetlb: defer freeing of huge pages if in non-task context
The following lockdep splat was observed when a certain hugetlbfs test
was run:

  ================================
  WARNING: inconsistent lock state
  4.18.0-159.el8.x86_64+debug #1 Tainted: G        W --------- -  -
  --------------------------------
  inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
  swapper/30/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
  ffffffff9acdc038 (hugetlb_lock){+.?.}, at: free_huge_page+0x36f/0xaa0
  {SOFTIRQ-ON-W} state was registered at:
    lock_acquire+0x14f/0x3b0
    _raw_spin_lock+0x30/0x70
    __nr_hugepages_store_common+0x11b/0xb30
    hugetlb_sysctl_handler_common+0x209/0x2d0
    proc_sys_call_handler+0x37f/0x450
    vfs_write+0x157/0x460
    ksys_write+0xb8/0x170
    do_syscall_64+0xa5/0x4d0
    entry_SYSCALL_64_after_hwframe+0x6a/0xdf
  irq event stamp: 691296
  hardirqs last  enabled at (691296): [<ffffffff99bb034b>] _raw_spin_unlock_irqrestore+0x4b/0x60
  hardirqs last disabled at (691295): [<ffffffff99bb0ad2>] _raw_spin_lock_irqsave+0x22/0x81
  softirqs last  enabled at (691284): [<ffffffff97ff0c63>] irq_enter+0xc3/0xe0
  softirqs last disabled at (691285): [<ffffffff97ff0ebe>] irq_exit+0x23e/0x2b0

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(hugetlb_lock);
    <Interrupt>
      lock(hugetlb_lock);

   *** DEADLOCK ***
      :
  Call Trace:
   <IRQ>
   __lock_acquire+0x146b/0x48c0
   lock_acquire+0x14f/0x3b0
   _raw_spin_lock+0x30/0x70
   free_huge_page+0x36f/0xaa0
   bio_check_pages_dirty+0x2fc/0x5c0
   clone_endio+0x17f/0x670 [dm_mod]
   blk_update_request+0x276/0xe50
   scsi_end_request+0x7b/0x6a0
   scsi_io_completion+0x1c6/0x1570
   blk_done_softirq+0x22e/0x350
   __do_softirq+0x23d/0xad8
   irq_exit+0x23e/0x2b0
   do_IRQ+0x11a/0x200
   common_interrupt+0xf/0xf
   </IRQ>

Both the hugetbl_lock and the subpool lock can be acquired in
free_huge_page().  One way to solve the problem is to make both locks
irq-safe.  However, Mike Kravetz had learned that the hugetlb_lock is
held for a linear scan of ALL hugetlb pages during a cgroup reparentling
operation.  So it is just too long to have irq disabled unless we can
break hugetbl_lock down into finer-grained locks with shorter lock hold
times.

Another alternative is to defer the freeing to a workqueue job.  This
patch implements the deferred freeing by adding a free_hpage_workfn()
work function to do the actual freeing.  The free_huge_page() call in a
non-task context saves the page to be freed in the hpage_freelist linked
list in a lockless manner using the llist APIs.

The generic workqueue is used to process the work, but a dedicated
workqueue can be used instead if it is desirable to have the huge page
freed ASAP.

Thanks to Kirill Tkhai <ktkhai@virtuozzo.com> for suggesting the use of
llist APIs which simplfy the code.

Link: http://lkml.kernel.org/r/20191217170331.30893-1-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-01-04 13:55:09 -08:00
..
kasan kasan: use apply_to_existing_page_range() for releasing vmalloc shadow 2019-12-17 20:59:59 -08:00
backing-dev.c bdi: Do not use freezable workqueue 2019-10-06 09:11:35 -06:00
balloon_compaction.c mm/balloon_compaction: suppress allocation warnings 2019-09-04 07:42:01 -04:00
cleancache.c Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
cma_debug.c mm/cma_debug.c: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops 2019-12-01 12:59:09 -08:00
cma.c mm/cma.c: switch to bitmap_zalloc() for cma bitmap allocation 2019-12-01 12:59:09 -08:00
cma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compaction.c mm, compaction: fix wrong pfn handling in __reset_isolation_pfn() 2019-10-14 15:04:01 -07:00
debug_page_ref.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debug.c mm/debug.c: PageAnon() is true for PageKsm() pages 2019-11-15 18:34:00 -08:00
dmapool.c mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options 2019-07-12 11:05:46 -07:00
early_ioremap.c mm/early_ioremap: Fix boot hang with earlyprintk=efi,keep 2017-12-11 14:54:44 +01:00
fadvise.c fs: Export generic_fadvise() 2019-08-30 22:43:58 -07:00
failslab.c mm/failslab.c: by default, do not fail allocations with direct reclaim only 2019-07-12 11:05:43 -07:00
filemap.c mm: drop mmap_sem before calling balance_dirty_pages() in write fault 2019-12-01 06:29:18 -08:00
frame_vector.c mm: untag user pointers in get_vaddr_frames 2019-09-25 17:51:41 -07:00
frontswap.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 482 2019-06-19 17:09:52 +02:00
gup_benchmark.c mm/gup: fix memory leak in __gup_benchmark_ioctl 2020-01-04 13:55:09 -08:00
gup.c mm/gup.c: fix comments of __get_user_pages() and get_user_pages_remote() 2019-12-01 06:29:18 -08:00
highmem.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
hmm.c mm/hmm: remove hmm_range_dma_map and hmm_range_dma_unmap 2019-11-23 19:56:45 -04:00
huge_memory.c mm/huge_memory.c: split_huge_pages_fops should be defined with DEFINE_DEBUGFS_ATTRIBUTE 2019-12-01 12:59:09 -08:00
hugetlb_cgroup.c mm: hugetlb: switch to css_tryget() in hugetlb_cgroup_charge_cgroup() 2019-11-15 18:34:00 -08:00
hugetlb.c mm/hugetlb: defer freeing of huge pages if in non-task context 2020-01-04 13:55:09 -08:00
hwpoison-inject.c mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops 2019-12-01 12:59:09 -08:00
init-mm.c mm/init-mm.c: include <linux/mman.h> for vm_committed_as_batch 2019-10-19 06:32:32 -04:00
internal.h mm, pcpu: make zone pcp updates and reset internal to the mm 2019-12-01 12:59:06 -08:00
interval_tree.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 248 2019-06-19 17:09:08 +02:00
Kconfig mm/Kconfig: fix trivial help text punctuation 2019-12-01 12:59:10 -08:00
Kconfig.debug mm, page_owner, debug_pagealloc: save and dump freeing stack trace 2019-09-24 15:54:08 -07:00
khugepaged.c mm/thp: flush file for !is_shmem PageDirty() case in collapse_file() 2019-12-01 12:59:09 -08:00
kmemleak-test.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333 2019-06-05 17:37:06 +02:00
kmemleak.c kmemleak: Do not corrupt the object_list during clean-up 2019-10-14 08:56:16 -07:00
ksm.c * PPC secure guest support 2019-12-04 11:08:30 -08:00
list_lru.c mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages 2019-07-12 11:05:44 -07:00
maccess.c uaccess: Add strict non-pagefault kernel-space read function 2019-11-02 12:39:12 -07:00
madvise.c mm/madvise.c: use PAGE_ALIGN[ED] for range checking 2019-12-01 12:59:09 -08:00
Makefile mm: Add write-protect and clean utilities for address space ranges 2019-11-06 13:03:36 +01:00
mapping_dirty_helpers.c mm: Add write-protect and clean utilities for address space ranges 2019-11-06 13:03:36 +01:00
memblock.c mm: support memblock alloc on the exact node for sparse_buffer_init() 2019-12-01 12:59:08 -08:00
memcontrol.c mm/memcontrol: use vmstat names for printing statistics 2019-12-04 19:44:11 -08:00
memfd.c mm: page cache: store only head pages in i_pages 2019-09-24 15:54:08 -07:00
memory_hotplug.c mm/memory_hotplug: shrink zones when offlining memory 2020-01-04 13:55:08 -08:00
memory-failure.c mm/memory-failure.c: use page_shift() in add_to_kill() 2019-12-01 12:59:04 -08:00
memory.c mm/memory.c: add apply_to_existing_page_range() helper 2019-12-17 20:59:59 -08:00
mempolicy.c mm/mempolicy.c: fix checking unmapped holes for mbind 2019-12-01 12:59:07 -08:00
mempool.c docs/core-api/mm: fix return value descriptions in mm/ 2019-03-05 21:07:20 -08:00
memremap.c mm/memory_hotplug: shrink zones when offlining memory 2020-01-04 13:55:08 -08:00
memtest.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
migrate.c mm: move_pages: return valid node id in status if the page is already on the target node 2020-01-04 13:55:09 -08:00
mincore.c mm: untag user pointers passed to memory syscalls 2019-09-25 17:51:41 -07:00
mlock.c mm: untag user pointers passed to memory syscalls 2019-09-25 17:51:41 -07:00
mm_init.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
mmap.c mm/mmap.c: make vma_merge() comment more easy to understand 2019-12-01 12:59:09 -08:00
mmu_context.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
mmu_gather.c mm: remove quicklist page table caches 2019-09-24 15:54:09 -07:00
mmu_notifier.c hmm related patches for 5.5 2019-11-30 10:33:14 -08:00
mmzone.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mprotect.c autonuma: reduce cache footprint when scanning page tables 2019-12-01 12:59:09 -08:00
mremap.c mm/mmap.c: use IS_ERR_VALUE to check return value of get_unmapped_area 2019-12-01 06:29:19 -08:00
msync.c mm: untag user pointers passed to memory syscalls 2019-09-25 17:51:41 -07:00
nommu.c mm/mmap.c: rb_parent is not necessary in __vma_link_list() 2019-12-01 06:29:19 -08:00
oom_kill.c mm/oom: fix pgtables units mismatch in Killed process message 2020-01-04 13:55:09 -08:00
page_alloc.c mm: clean up and clarify lruvec lookup procedure 2019-12-01 12:59:06 -08:00
page_counter.c memcg: introduce memory.min 2018-06-07 17:34:36 -07:00
page_ext.c mm, page_owner: fix off-by-one error in __set_page_owner_handle() 2019-10-14 15:04:00 -07:00
page_idle.c mm/page_idle.c: fix oops because end_pfn is larger than max_pfn 2019-06-29 16:43:45 +08:00
page_io.c mm/page_io.c: annotate refault stalls from swap_readpage 2019-12-01 12:59:11 -08:00
page_isolation.c mm/page_isolation.c: convert SKIP_HWPOISON to MEMORY_OFFLINE 2019-12-01 12:59:04 -08:00
page_owner.c mm/page_owner: don't access uninitialized memmaps when reading /proc/pagetypeinfo 2019-10-19 06:32:31 -04:00
page_poison.c mm/page_poison.c: fix a typo in a comment 2019-09-24 15:54:08 -07:00
page_vma_mapped.c mm: introduce page_size() 2019-09-24 15:54:08 -07:00
page-writeback.c writeback, memcg: Implement foreign dirty flushing 2019-08-27 09:22:38 -06:00
pagewalk.c mm: Add a walk_page_mapping() function to the pagewalk code 2019-11-06 13:02:43 +01:00
percpu-internal.h percpu: convert chunk hints to be based on pcpu_block_md 2019-03-13 12:25:31 -07:00
percpu-km.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
percpu-stats.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
percpu-vm.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
percpu.c percpu: Use struct_size() helper 2019-09-04 13:40:49 -07:00
pgtable-generic.c asm-generic/mm: stub out p{4,u}d_clear_bad() if __PAGETABLE_P{4,U}D_FOLDED 2019-12-01 06:29:19 -08:00
process_vm_access.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
readahead.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
rmap.c mm, thp: do not queue fully unmapped pages for deferred split 2019-12-01 12:59:09 -08:00
rodata_test.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
shmem.c mm/shmem.c: cast the type of unmap_start to u64 2019-12-01 12:59:10 -08:00
shuffle.c mm: fix -Wmissing-prototypes warnings 2019-10-07 15:47:19 -07:00
shuffle.h mm: maintain randomization of page free lists 2019-05-14 19:52:48 -07:00
slab_common.c mm: memcg/slab: wait for !root kmem_cache refcnt killing on root kmem_cache destruction 2019-12-04 19:44:11 -08:00
slab.c mm, slab: remove unused kmalloc_size() 2019-12-01 06:29:17 -08:00
slab.h mm: clean up and clarify lruvec lookup procedure 2019-12-01 12:59:06 -08:00
slob.c mm, sl[aou]b: guarantee natural alignment for kmalloc(power-of-two) 2019-10-07 15:47:20 -07:00
slub.c mm/slub.c: clean up validate_slab() 2019-12-01 06:29:18 -08:00
sparse-vmemmap.c mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap() 2019-07-18 17:08:07 -07:00
sparse.c mm: support memblock alloc on the exact node for sparse_buffer_init() 2019-12-01 12:59:08 -08:00
swap_cgroup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swap_slots.c mm, swap, get_swap_pages: use entry_size instead of cluster in parameter 2018-08-22 10:52:44 -07:00
swap_state.c mm: page cache: store only head pages in i_pages 2019-09-24 15:54:08 -07:00
swap.c mm/swap.c: piggyback lru_add_drain_all() calls 2019-12-01 06:29:19 -08:00
swapfile.c mm, swap: disallow swapon() on zoned block devices 2019-12-01 06:29:18 -08:00
truncate.c mm/thp: allow dropping THP from page cache 2019-10-19 06:32:33 -04:00
usercopy.c usercopy: Avoid HIGHMEM pfn warning 2019-09-17 15:20:17 -07:00
userfaultfd.c mm: fix typos in comments when calling __SetPageUptodate() 2019-12-01 12:59:10 -08:00
util.c mm/mmap.c: rb_parent is not necessary in __vma_link_list() 2019-12-01 06:29:19 -08:00
vmacache.c mm: get rid of vmacache_flush_all() entirely 2018-09-13 15:18:04 -10:00
vmalloc.c kasan: don't assume percpu shadow allocations will succeed 2019-12-17 20:59:59 -08:00
vmpressure.c mm/vmpressure.c: fix a signedness bug in vmpressure_register_event() 2019-10-07 15:47:19 -07:00
vmscan.c mm: vmscan: protect shrinker idr replace with CONFIG_MEMCG 2019-12-17 20:59:59 -08:00
vmstat.c mm/memcontrol: use vmstat names for printing statistics 2019-12-04 19:44:11 -08:00
workingset.c mm: vmscan: detect file thrashing at the reclaim root 2019-12-01 12:59:07 -08:00
z3fold.c mm/z3fold.c: add inter-page compaction 2019-12-01 12:59:07 -08:00
zbud.c treewide: Add SPDX license identifier for more missed files 2019-05-21 10:50:45 +02:00
zpool.c zpool: add malloc_support_movable to zpool_driver 2019-09-24 15:54:12 -07:00
zsmalloc.c mm/zsmalloc.c: fix the migrated zspage statistics. 2020-01-04 13:55:09 -08:00
zswap.c zswap: do not map same object twice 2019-09-24 15:54:12 -07:00