From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Thu, 7 Feb 2008 08:14:27 +0000 (-0800)
Subject: memory cgroup enhancements: add- pre_destroy() handler
X-Git-Tag: v2.6.25-rc1~446
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4fca88c87b7969c698912e2de9b1b31088c777cb;p=pandora-kernel.git

memory cgroup enhancements: add- pre_destroy() handler

Add a handler "pre_destroy" to cgroup_subsys.  It is called before
cgroup_rmdir() checks all subsys's refcnt.

I think this is useful for subsys which have some extra refs even if there
are no tasks in cgroup.  By adding pre_destroy(), the kernel keeps the rule
"destroy() against subsystem is called only when refcnt=0." and allows css
ref to be used by other objects than tasks.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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