kernel_optimize_test/mm
Hugh Dickins 245132643e SHM_UNLOCK: fix Unevictable pages stranded after swap
Commit cc39c6a9bb ("mm: account skipped entries to avoid looping in
find_get_pages") correctly fixed an infinite loop; but left a problem
that find_get_pages() on shmem would return 0 (appearing to callers to
mean end of tree) when it meets a run of nr_pages swap entries.

The only uses of find_get_pages() on shmem are via pagevec_lookup(),
called from invalidate_mapping_pages(), and from shmctl SHM_UNLOCK's
scan_mapping_unevictable_pages().  The first is already commented, and
not worth worrying about; but the second can leave pages on the
Unevictable list after an unusual sequence of swapping and locking.

Fix that by using shmem_find_get_pages_and_swap() (then ignoring the
swap) instead of pagevec_lookup().

But I don't want to contaminate vmscan.c with shmem internals, nor
shmem.c with LRU locking.  So move scan_mapping_unevictable_pages() into
shmem.c, renaming it shmem_unlock_mapping(); and rename
check_move_unevictable_page() to check_move_unevictable_pages(), looping
down an array of pages, oftentimes under the same lock.

Leave out the "rotate unevictable list" block: that's a leftover from
when this was used for /proc/sys/vm/scan_unevictable_pages, whose flawed
handling involved looking at pages at tail of LRU.

Was there significance to the sequence first ClearPageUnevictable, then
test page_evictable, then SetPageUnevictable here? I think not, we're
under LRU lock, and have no barriers between those.

Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shaohua.li@intel.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: <stable@vger.kernel.org> [back to 3.1 but will need respins]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-01-23 08:38:48 -08:00
..
backing-dev.c
bootmem.c mm: bootmem: try harder to free pages in bulk 2012-01-10 16:30:45 -08:00
bounce.c
cleancache.c
compaction.c mm: compaction: introduce sync-light migration for use by compaction 2012-01-12 20:13:09 -08:00
debug-pagealloc.c
dmapool.c
fadvise.c fadvise: only initiate writeback for specified range with FADV_DONTNEED 2012-01-10 16:30:43 -08:00
failslab.c switch debugfs to umode_t 2012-01-03 22:54:56 -05:00
filemap_xip.c
filemap.c memcg: add mem_cgroup_replace_page_cache() to fix LRU issue 2012-01-12 20:13:04 -08:00
fremap.c
highmem.c
huge_memory.c memcg: fix split_huge_page_refcounts() 2012-01-12 20:13:09 -08:00
hugetlb.c mm/hugetlb.c: undo change to page mapcount in fault handler 2012-01-23 08:38:48 -08:00
hwpoison-inject.c
init-mm.c
internal.h
Kconfig
Kconfig.debug mm: more intensive memory corruption debugging 2012-01-10 16:30:42 -08:00
kmemcheck.c
kmemleak-test.c
kmemleak.c
ksm.c memcg: clear pc->mem_cgroup if necessary. 2012-01-12 20:13:07 -08:00
maccess.c
madvise.c
Makefile
memblock.c
memcontrol.c mm: memcg: update the correct soft limit tree during migration 2012-01-23 08:38:48 -08:00
memory_hotplug.c mm: compaction: introduce sync-light migration for use by compaction 2012-01-12 20:13:09 -08:00
memory-failure.c mm: compaction: introduce sync-light migration for use by compaction 2012-01-12 20:13:09 -08:00
memory.c thp: add tlb_remove_pmd_tlb_entry 2012-01-12 20:13:08 -08:00
mempolicy.c mm: compaction: introduce sync-light migration for use by compaction 2012-01-12 20:13:09 -08:00
mempool.c mempool: fix first round failure behavior 2012-01-10 16:30:45 -08:00
migrate.c mm: compaction: introduce sync-light migration for use by compaction 2012-01-12 20:13:09 -08:00
mincore.c
mlock.c
mm_init.c
mmap.c mm: simplify find_vma_prev() 2012-01-10 16:30:44 -08:00
mmu_context.c
mmu_notifier.c
mmzone.c
mprotect.c
mremap.c mremap: enforce rmap src/dst vma ordering in case of vma_merge() succeeding in copy_vma() 2012-01-10 16:30:44 -08:00
msync.c
nobootmem.c
nommu.c
oom_kill.c mm: unify remaining mem_cont, mem, etc. variable names to memcg 2012-01-12 20:13:06 -08:00
page_alloc.c mm: __count_immobile_pages(): make sure the node is online 2012-01-23 08:38:47 -08:00
page_cgroup.c page_cgroup: drop multi CONFIG_MEMORY_HOTPLUG 2012-01-12 20:13:08 -08:00
page_io.c
page_isolation.c
page-writeback.c Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux 2012-01-10 16:59:59 -08:00
pagewalk.c
percpu-km.c
percpu-vm.c
percpu.c Kmemleak patches 2012-01-14 18:11:11 -08:00
pgtable-generic.c
prio_tree.c
process_vm_access.c
quicklist.c
readahead.c
rmap.c mm: unify remaining mem_cont, mem, etc. variable names to memcg 2012-01-12 20:13:06 -08:00
shmem.c SHM_UNLOCK: fix Unevictable pages stranded after swap 2012-01-23 08:38:48 -08:00
slab.c Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux 2012-01-11 18:52:23 -08:00
slob.c
slub.c mm,x86,um: move CMPXCHG_DOUBLE config option 2012-01-12 20:13:03 -08:00
sparse-vmemmap.c
sparse.c
swap_state.c memcg: clear pc->mem_cgroup if necessary. 2012-01-12 20:13:07 -08:00
swap.c mm: remove del_page_from_lru, add page_off_lru 2012-01-12 20:13:10 -08:00
swapfile.c mm: unify remaining mem_cont, mem, etc. variable names to memcg 2012-01-12 20:13:06 -08:00
thrash.c
truncate.c
util.c
vmalloc.c mm/vmalloc.c: eliminate extra loop in pcpu_get_vm_areas error path 2012-01-12 20:13:10 -08:00
vmscan.c SHM_UNLOCK: fix Unevictable pages stranded after swap 2012-01-23 08:38:48 -08:00
vmstat.c mm,x86,um: move CMPXCHG_LOCAL config option 2012-01-12 20:13:03 -08:00