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| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2008-02-07 09:14:27 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-07 17:42:20 +0100 |
| commit | 4fca88c87b7969c698912e2de9b1b31088c777cb (patch) | |
| tree | 6a086aaffb4ec17eadd2f2427c5816a02be6606f /kernel | |
| parent | memory cgroup enhancements: add memory.stat file (diff) | |
| download | linux-4fca88c87b7969c698912e2de9b1b31088c777cb.tar.xz linux-4fca88c87b7969c698912e2de9b1b31088c777cb.zip | |
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>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 4d67a39c58a8..4e8b16a8266c 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -586,6 +586,21 @@ static struct inode *cgroup_new_inode(mode_t mode, struct super_block *sb) return inode; } +/* + * Call subsys's pre_destroy handler. + * This is called before css refcnt check. + */ + +static void cgroup_call_pre_destroy(struct cgroup *cgrp) +{ + struct cgroup_subsys *ss; + for_each_subsys(cgrp->root, ss) + if (ss->pre_destroy && cgrp->subsys[ss->subsys_id]) + ss->pre_destroy(ss, cgrp); + return; +} + + static void cgroup_diput(struct dentry *dentry, struct inode *inode) { /* is dentry a directory ? if so, kfree() associated cgroup */ @@ -2160,6 +2175,13 @@ static int cgroup_rmdir(struct inode *unused_dir, struct dentry *dentry) parent = cgrp->parent; root = cgrp->root; sb = root->sb; + /* + * Call pre_destroy handlers of subsys + */ + cgroup_call_pre_destroy(cgrp); + /* + * Notify subsyses that rmdir() request comes. + */ if (cgroup_has_css_refs(cgrp)) { mutex_unlock(&cgroup_mutex); |