Roman Gushchin e1a366be5c mm: memcontrol: switch to rcu protection in drain_all_stock() ... Commit 72f0184c8a ("mm, memcg: remove hotplug locking from try_charge") introduced css_tryget()/css_put() calls in drain_all_stock(), which are supposed to protect the target memory cgroup from being released during the mem_cgroup_is_descendant() call. However, it's not completely safe. In theory, memcg can go away between reading stock->cached pointer and calling css_tryget(). This can happen if drain_all_stock() races with drain_local_stock() performed on the remote cpu as a result of a work, scheduled by the previous invocation of drain_all_stock(). The race is a bit theoretical and there are few chances to trigger it, but the current code looks a bit confusing, so it makes sense to fix it anyway. The code looks like as if css_tryget() and css_put() are used to protect stocks drainage. It's not necessary because stocked pages are holding references to the cached cgroup. And it obviously won't work for works, scheduled on other cpus. So, let's read the stock->cached pointer and evaluate the memory cgroup inside a rcu read section, and get rid of css_tryget()/css_put() calls. Link: http://lkml.kernel.org/r/20190802192241.3253165-1-guro@fb.com Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hdanton@sina.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2019-09-24 15:54:08 -07:00
..
kasan	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
backing-dev.c	writeback: Separate out wb_get_lookup() from wb_get_create()	2019-08-27 09:22:38 -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: fix the break condition in cma_maxchunk_get()	2019-05-14 09:47:45 -07:00
cma.c	mm/cma.c: fail if fixed declaration can't be honored	2019-07-16 19:23:21 -07:00
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: introduce compound_nr()	2019-09-24 15:54:08 -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: update references to page _refcount	2019-05-14 19:52:47 -07:00
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: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
frame_vector.c	mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()'	2017-12-14 16:00:48 -08:00
frontswap.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 482	2019-06-19 17:09:52 +02:00
gup_benchmark.c	mm/gup: replace get_user_pages_longterm() with FOLL_LONGTERM	2019-05-14 09:47:45 -07:00
gup.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
highmem.c	mm: convert totalram_pages and totalhigh_pages variables to atomic	2018-12-28 12:11:47 -08:00
hmm.c	pagewalk: separate function pointers from iterator data	2019-09-07 04:28:04 -03:00
huge_memory.c	mm: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
hugetlb_cgroup.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
hugetlb.c	hugetlbfs: fix hugetlb page migration/fault race causing SIGBUS	2019-08-13 16:06:53 -07:00
hwpoison-inject.c	hwpoison-inject: no need to check return value of debugfs_create functions	2019-06-03 15:39:40 +02:00
init-mm.c	mm: Allocate the mm_cpumask (mm->cpu_bitmap[]) dynamically based on nr_cpu_ids	2018-07-17 09:35:30 +02:00
internal.h	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
interval_tree.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 248	2019-06-19 17:09:08 +02:00
Kconfig	mm: remove CONFIG_MIGRATE_VMA_HELPER	2019-08-20 09:35:03 -03:00
Kconfig.debug	mm, page_owner, debug_pagealloc: save and dump freeing stack trace	2019-09-24 15:54:08 -07:00
khugepaged.c	mm: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
kmemleak-test.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 333	2019-06-05 17:37:06 +02:00
kmemleak.c	mm/kmemleak.c: record the current memory pool size	2019-09-24 15:54:07 -07:00
ksm.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 482	2019-06-19 17:09:52 +02:00
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	The main changes in this release include:	2019-07-18 11:51:00 -07:00
madvise.c	hmm related patches for 5.4	2019-09-21 10:07:42 -07:00
Makefile	memremap: move from kernel/ to mm/	2019-08-03 07:02:01 -07:00
memblock.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
memcontrol.c	mm: memcontrol: switch to rcu protection in drain_all_stock()	2019-09-24 15:54:08 -07:00
memfd.c	mm: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
memory_hotplug.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
memory-failure.c	HMM patches for 5.3	2019-07-14 19:42:11 -07:00
memory.c	vfs: don't allow writes to swap files	2019-08-20 07:55:16 -07:00
mempolicy.c	pagewalk: separate function pointers from iterator data	2019-09-07 04:28:04 -03:00
mempool.c	docs/core-api/mm: fix return value descriptions in mm/	2019-03-05 21:07:20 -08:00
memremap.c	Merge branch 'odp_fixes' into hmm.git	2019-08-21 20:58:18 -03:00
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: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
mincore.c	pagewalk: separate function pointers from iterator data	2019-09-07 04:28:04 -03:00
mlock.c	mm/mlock.c: change count_mm_mlocked_page_nr return type	2019-06-13 17:34:56 -10:00
mm_init.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
mmap.c	vfs: don't allow writes to swap files	2019-08-20 07:55:16 -07:00
mmu_context.c
mmu_gather.c	mm: mmu_gather: remove __tlb_reset_range() for force flush	2019-06-13 17:34:56 -10:00
mmu_notifier.c	mm, notifier: Catch sleeping/blocking for !blockable	2019-09-07 04:28:05 -03:00
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	pagewalk: separate function pointers from iterator data	2019-09-07 04:28:04 -03:00
mremap.c	mm/mmu_notifier: contextual information for event triggering invalidation	2019-05-14 09:47:49 -07:00
msync.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
nommu.c	mm: introduce page_size()	2019-09-24 15:54:08 -07:00
oom_kill.c	mm/oom_kill.c: remove redundant OOM score normalization in select_bad_process()	2019-07-12 11:05:47 -07:00
page_alloc.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
page_counter.c	memcg: introduce memory.min	2018-06-07 17:34:36 -07:00
page_ext.c	mm, debug_pagealloc: use a page type instead of page_ext flag	2019-07-12 11:05:43 -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, swap: use rbtree for swap_extent	2019-07-12 11:05:43 -07:00
page_isolation.c	mm/page_isolation.c: change the prototype of undo_isolate_page_range()	2019-07-12 11:05:43 -07:00
page_owner.c	mm, page_owner, debug_pagealloc: save and dump freeing stack trace	2019-09-24 15:54:08 -07:00
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	pagewalk: use lockdep_assert_held for locking validation	2019-09-07 04:28:04 -03:00
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	x86/mm: Page size aware flush_tlb_mm_range()	2018-10-09 16:51:11 +02:00
process_vm_access.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152	2019-05-30 11:26:32 -07:00
quicklist.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
readahead.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
rmap.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
rodata_test.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441	2019-06-05 17:37:17 +02:00
shmem.c	mm: page cache: store only head pages in i_pages	2019-09-24 15:54:08 -07:00
shuffle.c	mm: maintain randomization of page free lists	2019-05-14 19:52:48 -07:00
shuffle.h	mm: maintain randomization of page free lists	2019-05-14 19:52:48 -07:00
slab_common.c	mm, slab: extend slab/shrink to shrink all memcg caches	2019-09-24 15:54:07 -07:00
slab.c	mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options	2019-07-12 11:05:46 -07:00
slab.h	mm, slab: move memcg_cache_params structure to mm/slab.h	2019-09-24 15:54:07 -07:00
slob.c	mm: introduce page_size()	2019-09-24 15:54:08 -07:00
slub.c	mm: introduce page_size()	2019-09-24 15:54:08 -07:00
sparse-vmemmap.c	mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap()	2019-07-18 17:08:07 -07:00
sparse.c	mm/sparsemem: cleanup 'section number' data types	2019-07-18 17:08:07 -07:00
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: replace list_move_tail() with add_page_to_lru_list_tail()	2019-09-24 15:54:08 -07:00
swapfile.c	vfs: don't allow writes to swap files	2019-08-20 07:55:16 -07:00
truncate.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
usercopy.c	mm/usercopy: use memory range to be accessed for wraparound check	2019-08-13 16:06:52 -07:00
userfaultfd.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499	2019-06-19 17:09:53 +02:00
util.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
vmacache.c	mm: get rid of vmacache_flush_all() entirely	2018-09-13 15:18:04 -10:00
vmalloc.c	vmalloc: lift the arm flag for coherent mappings to common code	2019-09-04 11:13:19 +02:00
vmpressure.c	treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500	2019-06-19 17:09:55 +02:00
vmscan.c	mm: introduce compound_nr()	2019-09-24 15:54:08 -07:00
vmstat.c	treewide: Add SPDX license identifier for missed files	2019-05-21 10:50:45 +02:00
workingset.c	mm: workingset: fix vmstat counters for shadow nodes	2019-08-13 16:06:52 -07:00
z3fold.c	z3fold: fix retry mechanism in page reclaim	2019-09-24 15:54:06 -07:00
zbud.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
zpool.c	treewide: Add SPDX license identifier for more missed files	2019-05-21 10:50:45 +02:00
zsmalloc.c	mm/zsmalloc.c: fix build when CONFIG_COMPACTION=n	2019-08-30 18:00:50 -07:00
zswap.c	zswap: ignore debugfs_create_dir() return value	2019-06-03 15:39:39 +02:00