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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2011-07-26 19:08:26 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-26 19:49:42 -0400
commit82f9d486e59f588c7d100865c36510644abda356 (patch)
tree266f3dcf4f57538196bddd77a129adfb2752335b /Documentation/cgroups
parent108b6a78463bb8c7163e4f9779f36ad8bbade334 (diff)
memcg: add memory.vmscan_stat
The commit log of 0ae5e89c60c9 ("memcg: count the soft_limit reclaim in...") says it adds scanning stats to memory.stat file. But it doesn't because we considered we needed to make a concensus for such new APIs. This patch is a trial to add memory.scan_stat. This shows - the number of scanned pages(total, anon, file) - the number of rotated pages(total, anon, file) - the number of freed pages(total, anon, file) - the number of elaplsed time (including sleep/pause time) for both of direct/soft reclaim. The biggest difference with oringinal Ying's one is that this file can be reset by some write, as # echo 0 ...../memory.scan_stat Example of output is here. This is a result after make -j 6 kernel under 300M limit. [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.vmscan_stat scanned_pages_by_limit 9471864 scanned_anon_pages_by_limit 6640629 scanned_file_pages_by_limit 2831235 rotated_pages_by_limit 4243974 rotated_anon_pages_by_limit 3971968 rotated_file_pages_by_limit 272006 freed_pages_by_limit 2318492 freed_anon_pages_by_limit 962052 freed_file_pages_by_limit 1356440 elapsed_ns_by_limit 351386416101 scanned_pages_by_system 0 scanned_anon_pages_by_system 0 scanned_file_pages_by_system 0 rotated_pages_by_system 0 rotated_anon_pages_by_system 0 rotated_file_pages_by_system 0 freed_pages_by_system 0 freed_anon_pages_by_system 0 freed_file_pages_by_system 0 elapsed_ns_by_system 0 scanned_pages_by_limit_under_hierarchy 9471864 scanned_anon_pages_by_limit_under_hierarchy 6640629 scanned_file_pages_by_limit_under_hierarchy 2831235 rotated_pages_by_limit_under_hierarchy 4243974 rotated_anon_pages_by_limit_under_hierarchy 3971968 rotated_file_pages_by_limit_under_hierarchy 272006 freed_pages_by_limit_under_hierarchy 2318492 freed_anon_pages_by_limit_under_hierarchy 962052 freed_file_pages_by_limit_under_hierarchy 1356440 elapsed_ns_by_limit_under_hierarchy 351386416101 scanned_pages_by_system_under_hierarchy 0 scanned_anon_pages_by_system_under_hierarchy 0 scanned_file_pages_by_system_under_hierarchy 0 rotated_pages_by_system_under_hierarchy 0 rotated_anon_pages_by_system_under_hierarchy 0 rotated_file_pages_by_system_under_hierarchy 0 freed_pages_by_system_under_hierarchy 0 freed_anon_pages_by_system_under_hierarchy 0 freed_file_pages_by_system_under_hierarchy 0 elapsed_ns_by_system_under_hierarchy 0 total_xxxx is for hierarchy management. This will be useful for further memcg developments and need to be developped before we do some complicated rework on LRU/softlimit management. This patch adds a new struct memcg_scanrecord into scan_control struct. sc->nr_scanned at el is not designed for exporting information. For example, nr_scanned is reset frequentrly and incremented +2 at scanning mapped pages. To avoid complexity, I added a new param in scan_control which is for exporting scanning score. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: Andrew Bresticker <abrestic@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/cgroups')
-rw-r--r--Documentation/cgroups/memory.txt85
1 files changed, 84 insertions, 1 deletions
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 06eb6d957c83..6f3c598971fc 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -380,7 +380,7 @@ will be charged as a new owner of it.
380 380
3815.2 stat file 3815.2 stat file
382 382
383memory.stat file includes following statistics 3835.2.1 memory.stat file includes following statistics
384 384
385# per-memory cgroup local status 385# per-memory cgroup local status
386cache - # of bytes of page cache memory. 386cache - # of bytes of page cache memory.
@@ -438,6 +438,89 @@ Note:
438 file_mapped is accounted only when the memory cgroup is owner of page 438 file_mapped is accounted only when the memory cgroup is owner of page
439 cache.) 439 cache.)
440 440
4415.2.2 memory.vmscan_stat
442
443memory.vmscan_stat includes statistics information for memory scanning and
444freeing, reclaiming. The statistics shows memory scanning information since
445memory cgroup creation and can be reset to 0 by writing 0 as
446
447 #echo 0 > ../memory.vmscan_stat
448
449This file contains following statistics.
450
451[param]_[file_or_anon]_pages_by_[reason]_[under_heararchy]
452[param]_elapsed_ns_by_[reason]_[under_hierarchy]
453
454For example,
455
456 scanned_file_pages_by_limit indicates the number of scanned
457 file pages at vmscan.
458
459Now, 3 parameters are supported
460
461 scanned - the number of pages scanned by vmscan
462 rotated - the number of pages activated at vmscan
463 freed - the number of pages freed by vmscan
464
465If "rotated" is high against scanned/freed, the memcg seems busy.
466
467Now, 2 reason are supported
468
469 limit - the memory cgroup's limit
470 system - global memory pressure + softlimit
471 (global memory pressure not under softlimit is not handled now)
472
473When under_hierarchy is added in the tail, the number indicates the
474total memcg scan of its children and itself.
475
476elapsed_ns is a elapsed time in nanosecond. This may include sleep time
477and not indicates CPU usage. So, please take this as just showing
478latency.
479
480Here is an example.
481
482# cat /cgroup/memory/A/memory.vmscan_stat
483scanned_pages_by_limit 9471864
484scanned_anon_pages_by_limit 6640629
485scanned_file_pages_by_limit 2831235
486rotated_pages_by_limit 4243974
487rotated_anon_pages_by_limit 3971968
488rotated_file_pages_by_limit 272006
489freed_pages_by_limit 2318492
490freed_anon_pages_by_limit 962052
491freed_file_pages_by_limit 1356440
492elapsed_ns_by_limit 351386416101
493scanned_pages_by_system 0
494scanned_anon_pages_by_system 0
495scanned_file_pages_by_system 0
496rotated_pages_by_system 0
497rotated_anon_pages_by_system 0
498rotated_file_pages_by_system 0
499freed_pages_by_system 0
500freed_anon_pages_by_system 0
501freed_file_pages_by_system 0
502elapsed_ns_by_system 0
503scanned_pages_by_limit_under_hierarchy 9471864
504scanned_anon_pages_by_limit_under_hierarchy 6640629
505scanned_file_pages_by_limit_under_hierarchy 2831235
506rotated_pages_by_limit_under_hierarchy 4243974
507rotated_anon_pages_by_limit_under_hierarchy 3971968
508rotated_file_pages_by_limit_under_hierarchy 272006
509freed_pages_by_limit_under_hierarchy 2318492
510freed_anon_pages_by_limit_under_hierarchy 962052
511freed_file_pages_by_limit_under_hierarchy 1356440
512elapsed_ns_by_limit_under_hierarchy 351386416101
513scanned_pages_by_system_under_hierarchy 0
514scanned_anon_pages_by_system_under_hierarchy 0
515scanned_file_pages_by_system_under_hierarchy 0
516rotated_pages_by_system_under_hierarchy 0
517rotated_anon_pages_by_system_under_hierarchy 0
518rotated_file_pages_by_system_under_hierarchy 0
519freed_pages_by_system_under_hierarchy 0
520freed_anon_pages_by_system_under_hierarchy 0
521freed_file_pages_by_system_under_hierarchy 0
522elapsed_ns_by_system_under_hierarchy 0
523
4415.3 swappiness 5245.3 swappiness
442 525
443Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only. 526Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.