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5b280c0cc7
kernel-ark/mm
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Hugh Dickins 5b280c0cc7 mm: don't return 0 too early from find_get_pages() 
Callers of find_get_pages(), or its wrapper pagevec_lookup() - notably
truncate_inode_pages_range() - stop looking further when it returns 0.

But if an interrupt comes just after its radix_tree_gang_lookup_slot(),
especially if we have preemptible RCU enabled, isn't it conceivable that
all 14 pages returned could be removed from the page cache by
shrink_page_list(), before find_get_pages() gets to process them?  So
causing it to return 0 although there may be plenty more pages beyond.

Make find_get_pages() and find_get_pages_tag() check for this unlikely
case, and restart should it occur; but callers of find_get_pages_contig()
have no such expectation, it's okay for that to return 0 early.

I have not seen this in practice, just worried by the possibility.

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Salman Qazi <sqazi@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-22 17:44:04 -07:00
..
backing-dev.c
bootmem.c bootmem: Move contig_page_data definition to bootmem.c/nobootmem.c 2011-02-24 14:43:06 +01:00
bounce.c
compaction.c mm/compaction: check migrate_pages's return value instead of list_empty() 2011-03-22 17:44:00 -07:00
debug-pagealloc.c
dmapool.c mm/dmapool.c: use TASK_UNINTERRUPTIBLE in dma_pool_alloc() 2011-01-13 17:32:48 -08:00
fadvise.c
failslab.c
filemap_xip.c
filemap.c mm: don't return 0 too early from find_get_pages() 2011-03-22 17:44:04 -07:00
fremap.c
highmem.c
huge_memory.c thp+memcg-numa: fix BUG at include/linux/mm.h:370! 2011-03-14 08:29:50 -07:00
hugetlb.c hugetlbfs: correct handling of negative input to /proc/sys/vm/nr_hugepages 2011-03-22 17:44:04 -07:00
hwpoison-inject.c
init-mm.c
internal.h mm: export __get_user_pages 2011-03-17 13:08:27 -03:00
Kconfig mm: compaction: don't depend on HUGETLB_PAGE 2011-01-26 10:50:02 +10:00
Kconfig.debug mm: debug-pagealloc: fix kconfig dependency warning 2011-03-22 17:44:02 -07:00
kmemcheck.c
kmemleak-test.c kmemleak: remove memset by using kzalloc 2011-01-27 18:31:51 +00:00
kmemleak.c kmemleak: Allow kmemleak metadata allocations to fail 2011-01-27 18:32:06 +00:00
ksm.c mm: rename drop_anon_vma() to put_anon_vma() 2011-03-22 17:44:03 -07:00
maccess.c
madvise.c thp: khugepaged: make khugepaged aware about madvise 2011-01-13 17:32:47 -08:00
Makefile bootmem: Separate out CONFIG_NO_BOOTMEM code into nobootmem.c 2011-02-24 14:43:05 +01:00
memblock.c memblock: don't adjust size in memblock_find_base() 2011-02-11 16:12:20 -08:00
memcontrol.c pagewalk: only split huge pages when necessary 2011-03-22 17:44:04 -07:00
memory_hotplug.c Merge branch 'slub/hotplug' into slab/urgent 2011-01-15 13:28:17 +02:00
memory-failure.c mm: change __remove_from_page_cache() 2011-03-22 17:44:02 -07:00
memory.c mm: allow GUP to fail instead of waiting on a page 2011-03-22 17:44:02 -07:00
mempolicy.c mempolicy: remove redundant check in __mpol_equal() 2011-03-22 17:44:04 -07:00
mempool.c
migrate.c mm: rename drop_anon_vma() to put_anon_vma() 2011-03-22 17:44:03 -07:00
mincore.c thp: mincore transparent hugepage support 2011-01-13 17:32:44 -08:00
mlock.c mlock: operate on any regions with protection != PROT_NONE 2011-02-02 10:20:50 +11:00
mm_init.c
mmap.c brk: fix min_brk lower bound computation for COMPAT_BRK 2011-01-13 17:32:48 -08:00
mmu_context.c
mmu_notifier.c thp: mmu_notifier_test_young 2011-01-13 17:32:46 -08:00
mmzone.c mm: page allocator: adjust the per-cpu counter threshold when memory is low 2011-01-13 17:32:31 -08:00
mprotect.c thp: mprotect: transparent huge page support 2011-01-13 17:32:44 -08:00
mremap.c mm: fix possible cause of a page_mapped BUG 2011-02-23 21:55:06 -08:00
msync.c
nobootmem.c bootmem: Move __alloc_memory_core_early() to nobootmem.c 2011-02-24 14:43:06 +01:00
nommu.c mlock: do not hold mmap_sem for extended periods of time 2011-01-13 17:32:36 -08:00
oom_kill.c oom: suppress nodes that are not allowed from meminfo on oom kill 2011-03-22 17:44:01 -07:00
page_alloc.c mm: batch-free pcp list if possible 2011-03-22 17:44:02 -07:00
page_cgroup.c mm: notifier_from_errno() cleanup 2011-03-22 17:44:01 -07:00
page_io.c
page_isolation.c
page-writeback.c mm: reclaim invalidated page ASAP 2011-03-22 17:44:04 -07:00
pagewalk.c pagewalk: only split huge pages when necessary 2011-03-22 17:44:04 -07:00
percpu-km.c
percpu-vm.c mm: remove gfp mask from pcpu_get_vm_areas 2011-01-13 17:32:34 -08:00
percpu.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2011-01-13 10:05:56 -08:00
pgtable-generic.c mm/pgtable-generic.c: fix CONFIG_SWAP=n build 2011-01-26 10:49:58 +10:00
prio_tree.c
quicklist.c
readahead.c
rmap.c mm: simplify anon_vma refcounts 2011-03-22 17:44:03 -07:00
shmem.c mm: shmem: change remove_from_page_cache 2011-03-22 17:44:02 -07:00
slab.c mm: notifier_from_errno() cleanup 2011-03-22 17:44:01 -07:00
slob.c mm: Remove support for kmem_cache_name() 2011-01-23 21:00:05 +02:00
slub.c slub: Add statistics for this_cmpxchg_double failures 2011-03-22 20:48:04 +02:00
sparse-vmemmap.c
sparse.c thp: remove PG_buddy 2011-01-13 17:32:43 -08:00
swap_state.c thp: split_huge_page paging 2011-01-13 17:32:41 -08:00
swap.c mm: reclaim invalidated page ASAP 2011-03-22 17:44:04 -07:00
swapfile.c mm: swap: unlock swapfile inode mutex before closing file on bad swapfiles 2011-03-22 17:43:58 -07:00
thrash.c
truncate.c mm: deactivate invalidated pages 2011-03-22 17:44:03 -07:00
util.c kernel: kmem_ptr_validate considered harmful 2011-01-07 17:50:16 +11:00
vmalloc.c mm: vmap area cache 2011-03-22 17:44:00 -07:00
vmscan.c mm: vmscan: kswapd should not free an excessive number of pages when balancing small zones 2011-03-22 17:44:04 -07:00
vmstat.c thp: transparent hugepage vmstat 2011-01-13 17:32:43 -08:00