linux.git/Documentation/cgroups/memory.txt, branch v3.10

mm, memcg: add rss_huge stat to memory.stat

2013-05-08T01:38:26+00:00

This exports the amount of anonymous transparent hugepages for each
memcg via the new "rss_huge" stat in memory.stat.  The units are in
bytes.

This is helpful to determine the hugepage utilization for individual
jobs on the system in comparison to rss and opportunities where
MADV_HUGEPAGE may be helpful.

The amount of anonymous transparent hugepages is also included in "rss"
for backwards compatibility.

Signed-off-by: David Rientjes 
Acked-by: Michal Hocko 
Acked-by: Johannes Weiner 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-04-30T16:36:50+00:00

Pull trivial tree updates from Jiri Kosina:
 "Usual stuff, mostly comment fixes, typo fixes, printk fixes and small
  code cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (45 commits)
  mm: Convert print_symbol to %pSR
  gfs2: Convert print_symbol to %pSR
  m32r: Convert print_symbol to %pSR
  iostats.txt: add easy-to-find description for field 6
  x86 cmpxchg.h: fix wrong comment
  treewide: Fix typo in printk and comments
  doc: devicetree: Fix various typos
  docbook: fix 8250 naming in device-drivers
  pata_pdc2027x: Fix compiler warning
  treewide: Fix typo in printks
  mei: Fix comments in drivers/misc/mei
  treewide: Fix typos in kernel messages
  pm44xx: Fix comment for "CONFIG_CPU_IDLE"
  doc: Fix typo "CONFIG_CGROUP_CGROUP_MEMCG_SWAP"
  mmzone: correct "pags" to "pages" in comment.
  kernel-parameters: remove outdated 'noresidual' parameter
  Remove spurious _H suffixes from ifdef comments
  sound: Remove stray pluses from Kconfig file
  radio-shark: Fix printk "CONFIG_LED_CLASS"
  doc: put proper reference to CONFIG_MODULE_SIG_ENFORCE
  ...

memcg: add memory.pressure_level events

2013-04-29T22:54:38+00:00

With this patch userland applications that want to maintain the
interactivity/memory allocation cost can use the pressure level
notifications.  The levels are defined like this:

The "low" level means that the system is reclaiming memory for new
allocations.  Monitoring this reclaiming activity might be useful for
maintaining cache level.  Upon notification, the program (typically
"Activity Manager") might analyze vmstat and act in advance (i.e.
prematurely shutdown unimportant services).

The "medium" level means that the system is experiencing medium memory
pressure, the system might be making swap, paging out active file
caches, etc.  Upon this event applications may decide to further analyze
vmstat/zoneinfo/memcg or internal memory usage statistics and free any
resources that can be easily reconstructed or re-read from a disk.

The "critical" level means that the system is actively thrashing, it is
about to out of memory (OOM) or even the in-kernel OOM killer is on its
way to trigger.  Applications should do whatever they can to help the
system.  It might be too late to consult with vmstat or any other
statistics, so it's advisable to take an immediate action.

The events are propagated upward until the event is handled, i.e.  the
events are not pass-through.  Here is what this means: for example you
have three cgroups: A->B->C.  Now you set up an event listener on
cgroups A, B and C, and suppose group C experiences some pressure.  In
this situation, only group C will receive the notification, i.e.  groups
A and B will not receive it.  This is done to avoid excessive
"broadcasting" of messages, which disturbs the system and which is
especially bad if we are low on memory or thrashing.  So, organize the
cgroups wisely, or propagate the events manually (or, ask us to
implement the pass-through events, explaining why would you need them.)

Performance wise, the memory pressure notifications feature itself is
lightweight and does not require much of bookkeeping, in contrast to the
rest of memcg features.  Unfortunately, as of current memcg
implementation, pages accounting is an inseparable part and cannot be
turned off.  The good news is that there are some efforts[1] to improve
the situation; plus, implementing the same, fully API-compatible[2]
interface for CONFIG_MEMCG=n case (e.g.  embedded) is also a viable
option, so it will not require any changes on the userland side.

[1] http://permalink.gmane.org/gmane.linux.kernel.cgroups/6291
[2] http://lkml.org/lkml/2013/2/21/454

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix CONFIG_CGROPUPS=n warnings]
Signed-off-by: Anton Vorontsov 
Acked-by: Kirill A. Shutemov 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Tejun Heo 
Cc: David Rientjes 
Cc: Pekka Enberg 
Cc: Mel Gorman 
Cc: Glauber Costa 
Cc: Michal Hocko 
Cc: Luiz Capitulino 
Cc: Greg Thelen 
Cc: Leonid Moiseichuk 
Cc: KOSAKI Motohiro 
Cc: Minchan Kim 
Cc: Bartlomiej Zolnierkiewicz 
Cc: John Stultz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

doc: Fix typo "CONFIG_CGROUP_CGROUP_MEMCG_SWAP"

2013-03-27T13:14:02+00:00

Signed-off-by: Paul Bolle 
Acked-by: Rob Landley 
Signed-off-by: Jiri Kosina

kmem: add slab-specific documentation about the kmem controller

2012-12-18T23:02:15+00:00

Signed-off-by: Glauber Costa 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Frederic Weisbecker 
Cc: Greg Thelen 
Cc: Johannes Weiner 
Cc: JoonSoo Kim 
Cc: KAMEZAWA Hiroyuki 
Cc: Mel Gorman 
Cc: Michal Hocko 
Cc: Pekka Enberg 
Cc: Rik van Riel 
Cc: Suleiman Souhlal 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: add documentation about the kmem controller

2012-12-18T23:02:13+00:00

Signed-off-by: Glauber Costa 
Acked-by: Kamezawa Hiroyuki 
Acked-by: Michal Hocko 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Frederic Weisbecker 
Cc: Greg Thelen 
Cc: Johannes Weiner 
Cc: JoonSoo Kim 
Cc: Mel Gorman 
Cc: Pekka Enberg 
Cc: Rik van Riel 
Cc: Suleiman Souhlal 
Cc: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation/cgroups/memory.txt: s/mem_cgroup_charge/mem_cgroup_change_common/

2012-12-12T01:22:24+00:00

mem_cgroup_charge_common() is invoked as the entry point for cgroup limits
charge rather than mem_cgroup_charge(), as the later has been removed for
years.  Update the cgroup/memory.txt to reflect this change.

Signed-off-by: Jie Liu 
Cc: Ying Han 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: oom: fix totalpages calculation for memory.swappiness==0

2012-11-16T22:33:04+00:00

oom_badness() takes a totalpages argument which says how many pages are
available and it uses it as a base for the score calculation.  The value
is calculated by mem_cgroup_get_limit which considers both limit and
total_swap_pages (resp.  memsw portion of it).

This is usually correct but since fe35004fbf9e ("mm: avoid swapping out
with swappiness==0") we do not swap when swappiness is 0 which means
that we cannot really use up all the totalpages pages.  This in turn
confuses oom score calculation if the memcg limit is much smaller than
the available swap because the used memory (capped by the limit) is
negligible comparing to totalpages so the resulting score is too small
if adj!=0 (typically task with CAP_SYS_ADMIN or non zero oom_score_adj).
A wrong process might be selected as result.

The problem can be worked around by checking mem_cgroup_swappiness==0
and not considering swap at all in such a case.

Signed-off-by: Michal Hocko 
Acked-by: David Rientjes 
Acked-by: Johannes Weiner 
Acked-by: KOSAKI Motohiro 
Acked-by: KAMEZAWA Hiroyuki 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: trivial fixes for Documentation/cgroups/memory.txt

2012-10-09T07:22:54+00:00

While reading through Documentation/cgroups/memory.txt, I found a number
of minor wordos and typos.  The patch below is a conservative handling of
some of these: it provides just a number of "obviously correct" fixes to
the English that improve the readability of the document somewhat.
Obviously some more significant fixes need to be made to the document, but
some of those may not be in the "obvious correct" category.

Signed-off-by: Michael Kerrisk 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memcg: complete documentation for tcp memcg files

2012-08-01T01:42:43+00:00

Signed-off-by: Wanpeng Li 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds