kernel_optimize_test/Documentation/cgroups
KAMEZAWA Hiroyuki ec64f51545 cgroup: fix frequent -EBUSY at rmdir
In following situation, with memory subsystem,

	/groupA use_hierarchy==1
		/01 some tasks
		/02 some tasks
		/03 some tasks
		/04 empty

When tasks under 01/02/03 hit limit on /groupA, hierarchical reclaim
is triggered and the kernel walks tree under groupA. In this case,
rmdir /groupA/04 fails with -EBUSY frequently because of temporal
refcnt from the kernel.

In general. cgroup can be rmdir'd if there are no children groups and
no tasks. Frequent fails of rmdir() is not useful to users.
(And the reason for -EBUSY is unknown to users.....in most cases)

This patch tries to modify above behavior, by
	- retries if css_refcnt is got by someone.
	- add "return value" to pre_destroy() and allows subsystem to
	  say "we're really busy!"

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:54 -07:00
..
cgroups.txt cgroup: fix frequent -EBUSY at rmdir 2009-04-02 19:04:54 -07:00
cpuacct.txt cgroups: consolidate cgroup documents 2009-01-15 16:39:37 -08:00
cpusets.txt cpuset: various documentation fixes and updates 2009-02-20 17:57:49 -08:00
devices.txt cgroups: consolidate cgroup documents 2009-01-15 16:39:37 -08:00
freezer-subsystem.txt
memcg_test.txt memcg: update document to mention that swapoff should be tested 2009-01-29 18:04:44 -08:00
memory.txt cgroups: consolidate cgroup documents 2009-01-15 16:39:37 -08:00
resource_counter.txt cgroups: consolidate cgroup documents 2009-01-15 16:39:37 -08:00