The patch titled
memcg: fix documentation
has been added to the -mm tree. Its filename is
memcg-fix-documentation.patch
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Subject: memcg: fix documentation
From: Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx>
The description about various statistics from memory.stat is not accurate
and confusing at times.
Correct this along with a few other minor cleanups.
Signed-off-by: Bharata B Rao <bharata@xxxxxxxxxxxxxxxxxx>
Acked-by: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/cgroups/memory.txt | 53 ++++++++++++++++-------------
1 file changed, 31 insertions(+), 22 deletions(-)
diff -puN Documentation/cgroups/memory.txt~memcg-fix-documentation Documentation/cgroups/memory.txt
--- a/Documentation/cgroups/memory.txt~memcg-fix-documentation
+++ a/Documentation/cgroups/memory.txt
@@ -6,15 +6,14 @@ used here with the memory controller tha
Salient features
-a. Enable control of both RSS (mapped) and Page Cache (unmapped) pages
+a. Enable control of Anonymous, Page Cache (mapped and unmapped) and
+ Swap Cache memory pages.
b. The infrastructure allows easy addition of other types of memory to control
c. Provides *zero overhead* for non memory controller users
d. Provides a double LRU: global memory pressure causes reclaim from the
global LRU; a cgroup on hitting a limit, reclaims from the per
cgroup LRU
-NOTE: Swap Cache (unmapped) is not accounted now.
-
Benefits and Purpose of the memory controller
The memory controller isolates the memory behaviour of a group of tasks
@@ -290,34 +289,44 @@ will be charged as a new owner of it.
moved to the parent. If you want to avoid that, force_empty will be useful.
5.2 stat file
- memory.stat file includes following statistics (now)
- cache - # of pages from page-cache and shmem.
- rss - # of pages from anonymous memory.
- pgpgin - # of event of charging
- pgpgout - # of event of uncharging
- active_anon - # of pages on active lru of anon, shmem.
- inactive_anon - # of pages on active lru of anon, shmem
- active_file - # of pages on active lru of file-cache
- inactive_file - # of pages on inactive lru of file cache
- unevictable - # of pages cannot be reclaimed.(mlocked etc)
-
- Below is depend on CONFIG_DEBUG_VM.
- inactive_ratio - VM internal parameter. (see mm/page_alloc.c)
- recent_rotated_anon - VM internal parameter. (see mm/vmscan.c)
- recent_rotated_file - VM internal parameter. (see mm/vmscan.c)
- recent_scanned_anon - VM internal parameter. (see mm/vmscan.c)
- recent_scanned_file - VM internal parameter. (see mm/vmscan.c)
- Memo:
+memory.stat file includes following statistics
+
+cache - # of bytes of page cache memory.
+rss - # of bytes of anonymous and swap cache memory.
+pgpgin - # of pages paged in (equivalent to # of charging events).
+pgpgout - # of pages paged out (equivalent to # of uncharging events).
+active_anon - # of bytes of anonymous and swap cache memory on active
+ lru list.
+inactive_anon - # of bytes of anonymous memory and swap cache memory on
+ inactive lru list.
+active_file - # of bytes of file-backed memory on active lru list.
+inactive_file - # of bytes of file-backed memory on inactive lru list.
+unevictable - # of bytes of memory that cannot be reclaimed (mlocked etc).
+
+The following additional stats are dependent on CONFIG_DEBUG_VM.
+
+inactive_ratio - VM internal parameter. (see mm/page_alloc.c)
+recent_rotated_anon - VM internal parameter. (see mm/vmscan.c)
+recent_rotated_file - VM internal parameter. (see mm/vmscan.c)
+recent_scanned_anon - VM internal parameter. (see mm/vmscan.c)
+recent_scanned_file - VM internal parameter. (see mm/vmscan.c)
+
+Memo:
recent_rotated means recent frequency of lru rotation.
recent_scanned means recent # of scans to lru.
showing for better debug please see the code for meanings.
+Note:
+ Only anonymous and swap cache memory is listed as part of 'rss' stat.
+ This should not be confused with the true 'resident set size' or the
+ amount of physical memory used by the cgroup. Per-cgroup rss
+ accounting is not done yet.
5.3 swappiness
Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
- Following cgroup's swapiness can't be changed.
+ Following cgroups' swapiness can't be changed.
- root cgroup (uses /proc/sys/vm/swappiness).
- a cgroup which uses hierarchy and it has child cgroup.
- a cgroup which uses hierarchy and not the root of hierarchy.
_
Patches currently in -mm which might be from bharata@xxxxxxxxxxxxxxxxxx are
origin.patch
memcg-fix-documentation.patch
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