linux/mm
KAMEZAWA Hiroyuki 246e87a939 memcg: fix get_scan_count() for small targets
During memory reclaim we determine the number of pages to be scanned per
zone as

	(anon + file) >> priority.
Assume
	scan = (anon + file) >> priority.

If scan < SWAP_CLUSTER_MAX, the scan will be skipped for this time and
priority gets higher.  This has some problems.

  1. This increases priority as 1 without any scan.
     To do scan in this priority, amount of pages should be larger than 512M.
     If pages>>priority < SWAP_CLUSTER_MAX, it's recorded and scan will be
     batched, later. (But we lose 1 priority.)
     If memory size is below 16M, pages >> priority is 0 and no scan in
     DEF_PRIORITY forever.

  2. If zone->all_unreclaimabe==true, it's scanned only when priority==0.
     So, x86's ZONE_DMA will never be recoverred until the user of pages
     frees memory by itself.

  3. With memcg, the limit of memory can be small. When using small memcg,
     it gets priority < DEF_PRIORITY-2 very easily and need to call
     wait_iff_congested().
     For doing scan before priorty=9, 64MB of memory should be used.

Then, this patch tries to scan SWAP_CLUSTER_MAX of pages in force...when

  1. the target is enough small.
  2. it's kswapd or memcg reclaim.

Then we can avoid rapid priority drop and may be able to recover
all_unreclaimable in a small zones.  And this patch removes nr_saved_scan.
 This will allow scanning in this priority even when pages >> priority is
very small.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Ying Han <yinghan@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 17:12:35 -07:00
..
backing-dev.c backing-dev: Kill set but not used var in bdi_debug_stats_show() 2011-05-20 21:23:37 +02:00
bootmem.c
bounce.c
cleancache.c mm: cleancache core ops functions and config 2011-05-26 10:01:36 -06:00
compaction.c
debug-pagealloc.c
dmapool.c
fadvise.c
failslab.c
filemap_xip.c mm: Convert i_mmap_lock to a mutex 2011-05-25 08:39:18 -07:00
filemap.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem 2011-05-26 10:50:56 -07:00
fremap.c mm: don't access vm_flags as 'int' 2011-05-26 09:20:31 -07:00
highmem.c
huge_memory.c mm: thp: optimize memcg charge in khugepaged 2011-05-25 08:39:21 -07:00
hugetlb.c mm: don't access vm_flags as 'int' 2011-05-26 09:20:31 -07:00
hwpoison-inject.c Fix common misspellings 2011-03-31 11:26:23 -03:00
init-mm.c mm: convert mm->cpu_vm_cpumask into cpumask_var_t 2011-05-25 08:39:21 -07:00
internal.h mm: nommu: sort mm->mmap list properly 2011-05-25 08:39:05 -07:00
Kconfig mm: cleancache core ops functions and config 2011-05-26 10:01:36 -06:00
Kconfig.debug
kmemcheck.c
kmemleak-test.c
kmemleak.c kmemleak: Do not return a pointer to an object that kmemleak did not get 2011-05-19 17:35:28 +01:00
ksm.c oom: replace PF_OOM_ORIGIN with toggling oom_score_adj 2011-05-25 08:39:10 -07:00
maccess.c
madvise.c
Makefile mm: cleancache core ops functions and config 2011-05-26 10:01:36 -06:00
memblock.c
memcontrol.c memcg: reclaim memory from nodes in round-robin order 2011-05-26 17:12:35 -07:00
memory_hotplug.c mm: remove dependency on CONFIG_FLATMEM from online_page() 2011-05-25 08:39:28 -07:00
memory-failure.c vmscan: change shrinker API by passing shrink_control struct 2011-05-25 08:39:26 -07:00
memory.c mm: don't access vm_flags as 'int' 2011-05-26 09:20:31 -07:00
mempolicy.c mm: proc: move show_numa_map() to fs/proc/task_mmu.c 2011-05-25 08:39:34 -07:00
mempool.c
migrate.c mm: use refcounts for page_lock_anon_vma() 2011-05-25 08:39:19 -07:00
mincore.c
mlock.c mm: don't access vm_flags as 'int' 2011-05-26 09:20:31 -07:00
mm_init.c
mmap.c mm: don't access vm_flags as 'int' 2011-05-26 09:20:31 -07:00
mmu_context.c
mmu_notifier.c
mmzone.c
mprotect.c
mremap.c mm: Convert i_mmap_lock to a mutex 2011-05-25 08:39:18 -07:00
msync.c
nobootmem.c memblock/nobootmem: remove unneeded code from alloc_bootmem_node_high() 2011-05-25 08:39:31 -07:00
nommu.c nommu: add page alignment to mmap 2011-05-25 08:39:38 -07:00
oom_kill.c oom: replace PF_OOM_ORIGIN with toggling oom_score_adj 2011-05-25 08:39:10 -07:00
page_alloc.c memcg: fix get_scan_count() for small targets 2011-05-26 17:12:35 -07:00
page_cgroup.c memcg: move page-freeing code out of lock 2011-05-26 17:12:35 -07:00
page_io.c
page_isolation.c
page-writeback.c
pagewalk.c
percpu-km.c
percpu-vm.c
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
prio_tree.c sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00
quicklist.c
readahead.c readahead: readahead page allocations are OK to fail 2011-05-25 08:39:25 -07:00
rmap.c mm: optimize page_lock_anon_vma() fast-path 2011-05-25 08:39:20 -07:00
shmem.c tmpfs: implement generic xattr support 2011-05-25 08:39:31 -07:00
slab.c sanitize <linux/prefetch.h> usage 2011-05-20 12:50:29 -07:00
slob.c
slub.c slub: remove no-longer used 'unlock_out' label 2011-05-25 18:06:54 -07:00
sparse-vmemmap.c
sparse.c Fix common misspellings 2011-03-31 11:26:23 -03:00
swap_state.c
swap.c mm: batch activate_page() to reduce lock contention 2011-05-25 08:39:37 -07:00
swapfile.c oom: replace PF_OOM_ORIGIN with toggling oom_score_adj 2011-05-25 08:39:10 -07:00
thrash.c
truncate.c mm/fs: add hooks to support cleancache 2011-05-26 10:01:43 -06:00
util.c mm: nommu: sort mm->mmap list properly 2011-05-25 08:39:05 -07:00
vmalloc.c mm: print vmalloc() state after allocation failures 2011-05-25 08:39:22 -07:00
vmscan.c memcg: fix get_scan_count() for small targets 2011-05-26 17:12:35 -07:00
vmstat.c mm, mem-hotplug: update pcp->stat_threshold when memory hotplug occur 2011-05-25 08:39:09 -07:00