Hugh Dickins 3d470fc385 mm: munlock use mapcount to avoid terrible overhead ... A process spent 30 minutes exiting, just munlocking the pages of a large anonymous area that had been alternately mprotected into page-sized vmas: for every single page there's an anon_vma walk through all the other little vmas to find the right one. A general fix to that would be a lot more complicated (use prio_tree on anon_vma?), but there's one very simple thing we can do to speed up the common case: if a page to be munlocked is mapped only once, then it is our vma that it is mapped into, and there's no need whatever to walk through all the others. Okay, there is a very remote race in munlock_vma_pages_range(), if between its follow_page() and lock_page(), another process were to munlock the same page, then page reclaim remove it from our vma, then another process mlock it again. We would find it with page_mapcount 1, yet it's still mlocked in another process. But never mind, that's much less likely than the down_read_trylock() failure which munlocking already tolerates (in try_to_unmap_one()): in due course page reclaim will discover and move the page to unevictable instead. [akpm@linux-foundation.org: add comment] Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2011-10-31 17:30:51 -07:00
..
backing-dev.c	mm-add-comment-explaining-task-state-setting-in-bdi_forker_thread-fix	2011-10-31 17:30:49 -07:00
bootmem.c	crash_dump: export is_kdump_kernel to modules, consolidate elfcorehdr_addr, setup_elfcorehdr and saved_max_pfn	2011-03-23 19:47:19 -07:00
bounce.c	bounce: call flush_dcache_page() after bounce_copy_vec()	2010-09-09 18:57:25 -07:00
cleancache.c	mm: cleancache core ops functions and config	2011-05-26 10:01:36 -06:00
compaction.c	mm: compaction: make compact_zone_order() static	2011-10-31 17:30:49 -07:00
debug-pagealloc.c	debug-pagealloc: add support for highmem pages	2011-10-31 17:30:48 -07:00
dmapool.c	devres: fix possible use after free	2011-07-25 20:57:14 -07:00
fadvise.c	readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM	2010-03-06 11:26:25 -08:00
failslab.c	fault-injection: add ability to export fault_attr in arbitrary directory	2011-08-03 14:25:20 -10:00
filemap_xip.c	mm: Convert i_mmap_lock to a mutex	2011-05-25 08:39:18 -07:00
filemap.c	vfs: iov_iter: have iov_iter_advance decrement nr_segs appropriately	2011-10-28 13:55:08 +02:00
fremap.c	mm: don't access vm_flags as 'int'	2011-05-26 09:20:31 -07:00
highmem.c	mm: fix kunmap_high() comment	2011-10-31 17:30:49 -07:00
huge_memory.c	mm/huge_memory: fix typo when updating mmu cache	2011-10-31 17:30:51 -07:00
hugetlb.c	mm: hugetlb: fix coding style issues	2011-07-25 20:57:09 -07:00
hwpoison-inject.c	Fix common misspellings	2011-03-31 11:26:23 -03:00
init-mm.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
internal.h	mm: nommu: sort mm->mmap list properly	2011-05-25 08:39:05 -07:00
Kconfig	memblock: add NO_BOOTMEM config symbol	2011-10-31 17:30:47 -07:00
Kconfig.debug	mm: debug-pagealloc: fix kconfig dependency warning	2011-03-22 17:44:02 -07:00
kmemcheck.c	kmemcheck: Fix build errors due to missing slab.h	2010-03-30 22:02:32 +09:00
kmemleak-test.c	kmemleak: remove memset by using kzalloc	2011-01-27 18:31:51 +00:00
kmemleak.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
ksm.c	oom: fix race while temporarily setting current's oom_score_adj	2011-10-31 17:30:45 -07:00
maccess.c	maccess,probe_kernel: Make write/read src const void *	2011-05-25 19:56:23 -04:00
madvise.c	fs: kill i_alloc_sem	2011-07-20 20:47:46 -04:00
Makefile	Cross Memory Attach	2011-10-31 17:30:44 -07:00
memblock.c	mm/memblock.c: quiet sparse noise	2011-10-31 17:30:50 -07:00
memcontrol.c	mm: change isolate mode from #define to bitwise type	2011-10-31 17:30:44 -07:00
memory_hotplug.c	mm: extend memory hotplug API to allow memory hotplug in virtual machines	2011-07-25 20:57:08 -07:00
memory-failure.c	HWPOISON: convert pr_debug()s to pr_info()s	2011-10-31 17:30:49 -07:00
memory.c	mm/futex: fix futex writes on archs with SW tracking of dirty & young	2011-07-25 20:57:11 -07:00
mempolicy.c	mm/mempolicy.c: quiet sparse noise	2011-10-31 17:30:50 -07:00
mempool.c	mm: remove broken 'kzalloc' mempool	2009-09-22 07:17:35 -07:00
migrate.c	mm: migration: clean up unmap_and_move()	2011-10-31 17:30:45 -07:00
mincore.c	mm: clarify the radix_tree exceptional cases	2011-08-03 14:25:24 -10:00
mlock.c	mm: munlock use mapcount to avoid terrible overhead	2011-10-31 17:30:51 -07:00
mm_init.c
mmap.c	mm/mmap.c: eliminate the ret variable from mm_take_all_locks()	2011-10-31 17:30:49 -07:00
mmu_context.c	exit: fix oops in sync_mm_rss	2010-03-24 16:31:21 -07:00
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	thp: mremap support and TLB optimization	2011-10-31 17:30:48 -07:00
msync.c	sanitize vfs_fsync calling conventions	2010-05-21 18:31:21 -04:00
nobootmem.c	memblock/nobootmem: remove unneeded code from alloc_bootmem_node_high()	2011-05-25 08:39:31 -07:00
nommu.c	mmap: fix and tidy up overcommit page arithmetic	2011-07-25 20:57:09 -07:00
oom_kill.c	oom: fix race while temporarily setting current's oom_score_adj	2011-10-31 17:30:45 -07:00
page_alloc.c	mm: neaten warn_alloc_failed	2011-10-31 17:30:48 -07:00
page_cgroup.c	mm: Convert vmalloc/memset to vzalloc	2011-09-15 13:56:56 +02:00
page_io.c	block: kill off REQ_UNPLUG	2011-03-10 08:52:27 +01:00
page_isolation.c	mm: page_isolation: codeclean fix comment and rm unneeded val init	2010-10-26 16:52:11 -07:00
page-writeback.c	mm/page-writeback.c: document bdi_min_ratio	2011-10-31 17:30:45 -07:00
pagewalk.c	pagewalk: fix code comment for THP	2011-07-25 20:57:09 -07:00
percpu-km.c	percpu: clear memory allocated with the km allocator	2010-10-02 10:28:42 +03:00
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-2.6.40' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu	2011-05-24 11:53:42 -07:00
pgtable-generic.c	mm/pgtable-generic.c: fix CONFIG_SWAP=n build	2011-01-26 10:49:58 +10:00
prio_tree.c	sanitize <linux/prefetch.h> usage	2011-05-20 12:50:29 -07:00
process_vm_access.c	Cross Memory Attach	2011-10-31 17:30:44 -07:00
quicklist.c	include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h	2010-03-30 22:02:32 +09:00
readahead.c	readahead: readahead page allocations are OK to fail	2011-05-25 08:39:25 -07:00
rmap.c	ksm: fix the comment of try_to_unmap_one()	2011-10-31 17:30:49 -07:00
shmem.c	vmscan: add barrier to prevent evictable page in unevictable list	2011-10-31 17:30:50 -07:00
slab.c	mm: restrict access to slab files under procfs and sysfs	2011-09-27 22:59:27 +03:00
slob.c	atomic: use <linux/atomic.h>	2011-07-26 16:49:47 -07:00
slub.c	lib/string.c: introduce memchr_inv()	2011-10-31 17:30:47 -07:00
sparse-vmemmap.c	tree-wide: fix comment/printk typos	2010-11-01 15:38:34 -04:00
sparse.c	mm: make some struct page's const	2011-07-25 20:57:07 -07:00
swap_state.c	block: remove per-queue plugging	2011-03-10 08:52:07 +01:00
swap.c	mm: batch activate_page() to reduce lock contention	2011-05-25 08:39:37 -07:00
swapfile.c	oom: fix race while temporarily setting current's oom_score_adj	2011-10-31 17:30:45 -07:00
thrash.c	mm/thrash.c: quiet sparse noise	2011-10-31 17:30:50 -07:00
truncate.c	mm: a few small updates for radix-swap	2011-08-03 14:25:24 -10:00
util.c	mm: nommu: sort mm->mmap list properly	2011-05-25 08:39:05 -07:00
vmalloc.c	mm/vmalloc.c: report more vmalloc failures	2011-10-31 17:30:48 -07:00
vmscan.c	vmscan: abort reclaim/compaction if compaction can proceed	2011-10-31 17:30:50 -07:00
vmstat.c	mm: vmscan: immediately reclaim end-of-LRU dirty pages when writeback completes	2011-10-31 17:30:47 -07:00