linux-toradex.git/include/linux/res_counter.h, branch v2.6.35.4

memcg: some modification to softlimit under hierarchical memory reclaim.

2009-10-01T23:11:13+00:00

This patch clean up/fixes for memcg's uncharge soft limit path.

Problems:
  Now, res_counter_charge()/uncharge() handles softlimit information at
  charge/uncharge and softlimit-check is done when event counter per memcg
  goes over limit. Now, event counter per memcg is updated only when
  memory usage is over soft limit. Here, considering hierarchical memcg
  management, ancesotors should be taken care of.

  Now, ancerstors(hierarchy) are handled in charge() but not in uncharge().
  This is not good.

  Prolems:
  1. memcg's event counter incremented only when softlimit hits. That's bad.
     It makes event counter hard to be reused for other purpose.

  2. At uncharge, only the lowest level rescounter is handled. This is bug.
     Because ancesotor's event counter is not incremented, children should
     take care of them.

  3. res_counter_uncharge()'s 3rd argument is NULL in most case.
     ops under res_counter->lock should be small. No "if" sentense is better.

Fixes:
  * Removed soft_limit_xx poitner and checks in charge and uncharge.
    Do-check-only-when-necessary scheme works enough well without them.

  * make event-counter of memcg incremented at every charge/uncharge.
    (per-cpu area will be accessed soon anyway)

  * All ancestors are checked at soft-limit-check. This is necessary because
    ancesotor's event counter may never be modified. Then, they should be
    checked at the same time.

Reviewed-by: Daisuke Nishimura 
Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Paul Menage 
Cc: Li Zefan 
Cc: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory controller: soft limit organize cgroups

2009-09-24T14:20:59+00:00

Organize cgroups over soft limit in a RB-Tree

Introduce an RB-Tree for storing memory cgroups that are over their soft
limit.  The overall goal is to

1. Add a memory cgroup to the RB-Tree when the soft limit is exceeded.
   We are careful about updates, updates take place only after a particular
   time interval has passed
2. We remove the node from the RB-Tree when the usage goes below the soft
   limit

The next set of patches will exploit the RB-Tree to get the group that is
over its soft limit by the largest amount and reclaim from it, when we
face memory contention.

[hugh.dickins@tiscali.co.uk: CONFIG_CGROUP_MEM_RES_CTLR=y CONFIG_PREEMPT=y fails to boot]
Signed-off-by: Balbir Singh 
Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Li Zefan 
Cc: KOSAKI Motohiro 
Signed-off-by: Hugh Dickins 
Cc: Jiri Slaby 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memory controller: soft limit interface

2009-09-24T14:20:59+00:00

Add an interface to allow get/set of soft limits.  Soft limits for memory
plus swap controller (memsw) is currently not supported.  Resource
counters have been enhanced to support soft limits and new type
RES_SOFT_LIMIT has been added.  Unlike hard limits, soft limits can be
directly set and do not need any reclaim or checks before setting them to
a newer value.

Kamezawa-San raised a question as to whether soft limit should belong to
res_counter.  Since all resources understand the basic concepts of hard
and soft limits, it is justified to add soft limits here.  Soft limits are
a generic resource usage feature, even file system quotas support soft
limits.

Signed-off-by: Balbir Singh 
Cc: KAMEZAWA Hiroyuki 
Cc: Li Zefan 
Cc: KOSAKI Motohiro 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: add interface to reset limits

2009-06-18T20:03:48+00:00

We don't have an interface to reset mem.limit or memsw.limit now.

This patch allows to reset mem.limit or memsw.limit when they are being
set to -1.

Signed-off-by: Daisuke Nishimura 
Cc: KAMEZAWA Hiroyuki 
Cc: Balbir Singh 
Cc: Li Zefan 
Cc: Dhaval Giani 
Cc: YAMAMOTO Takashi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: consolidate cgroup documents

2009-01-16T00:39:37+00:00

Move Documentation/cpusets.txt and Documentation/controllers/* to
Documentation/cgroups/

Signed-off-by: Li Zefan 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Balbir Singh 
Acked-by: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: memory cgroup resource counters for hierarchy

2009-01-08T16:31:05+00:00

Add support for building hierarchies in resource counters.  Cgroups allows
us to build a deep hierarchy, but we currently don't link the resource
counters belonging to the memory controller control groups, in the same
fashion as the corresponding cgroup entries in the cgroup hierarchy.  This
patch provides the infrastructure for resource counters that have the same
hiearchy as their cgroup counter parts.

These set of patches are based on the resource counter hiearchy patches
posted by Pavel Emelianov.

NOTE: Building hiearchies is expensive, deeper hierarchies imply charging
the all the way up to the root.  It is known that hiearchies are
expensive, so the user needs to be careful and aware of the trade-offs
before creating very deep ones.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Balbir Singh 
Cc: YAMAMOTO Takashi 
Cc: Paul Menage 
Cc: Li Zefan 
Cc: David Rientjes 
Cc: Pavel Emelianov 
Cc: Dhaval Giani 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

res_counter: fix off-by-one bug in setting limit

2008-09-05T21:39:37+00:00

I found we can no longer set limit to 0 with 2.6.27-rcX:
 # mount -t cgroup -omemory xxx /mnt
 # mkdir /mnt/0
 # echo 0 > /mnt/0/memory.limit_in_bytes
 bash: echo: write error: Device or resource busy

It turned out 'limit' can't be set to 'usage', which is wrong IMO.

Signed-off-by: Li Zefan 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Balbir Singh 
Acked-by: Pavel Emelyanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

res_counter: limit change support ebusy

2008-07-25T17:53:37+00:00

Add an interface to set limit.  This is necessary to memory resource
controller because it shrinks usage at set limit.

Other controllers may not need this interface to shrink usage because
shrinking is not necessary or impossible.

Acked-by: Balbir Singh 
Acked-by: Pavel Emelyanov 
Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Paul Menage 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup files: convert res_counter_write() to be a cgroups write_string() handler

2008-07-25T17:53:36+00:00

Currently res_counter_write() is a raw file handler even though it's
ultimately taking a number, since in some cases it wants to
pre-process the string when converting it to a number.

This patch converts res_counter_write() from a raw file handler to a
write_string() handler; this allows some of the boilerplate
copying/locking/checking to be removed, and simplies the cleanup path,
since these functions are now performed by the cgroups framework.

[lizf@cn.fujitsu.com: build fix]
Signed-off-by: Paul Menage 
Cc: Paul Jackson 
Cc: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: Serge Hallyn 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Li Zefan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Mark res_counter_charge(_locked) with __must_check

2008-07-25T17:53:35+00:00

Ignoring their return values may result in counter underflow in the future -
when the value charged will be uncharged (or in "leaks" - when the value is
not uncharged).

This also prevents from using charging routines to decrement the
counter value (i.e. uncharge it) ;)

(Current code works OK with res_counter, however :) )

Signed-off-by: Pavel Emelyanov 
Cc: Balbir Singh 
Cc: Paul Menage 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds