From: Paul Menage <menage@google.com>
To: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: linux-mm <linux-mm@kvack.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Li Zefan <lizf@cn.fujitsu.com>
Subject: Re: [RFC][PATCH 1/8] cgroup: introduce cancel_attach()
Date: Thu, 15 Oct 2009 00:37:23 -0700 [thread overview]
Message-ID: <6599ad830910150037j7aca0020mfbe29d6c03befbf7@mail.gmail.com> (raw)
In-Reply-To: <20091013135027.c60285a8.nishimura@mxp.nes.nec.co.jp>
On Mon, Oct 12, 2009 at 9:50 PM, Daisuke Nishimura
<nishimura@mxp.nes.nec.co.jp> wrote:
> int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> {
> int retval = 0;
> - struct cgroup_subsys *ss;
> + struct cgroup_subsys *ss, *fail = NULL;
Maybe give this a more descriptive name, such as "failed_subsys" ?
> @@ -1553,8 +1553,10 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
> for_each_subsys(root, ss) {
> if (ss->can_attach) {
> retval = ss->can_attach(ss, cgrp, tsk, false);
> - if (retval)
> - return retval;
> + if (retval) {
> + fail = ss;
Comment here on why you set "fail" ?
> +out:
> + if (retval)
> + for_each_subsys(root, ss) {
> + if (ss == fail)
Comment here?
The problem with this API is that the subsystem doesn't know how long
it needs to hold on to the potential rollback state for. The design
for transactional cgroup attachment that I sent out over a year ago
presented a more robust API, but I've not had time to work on it. So
maybe this patch could be a stop-gap.
Paul
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next prev parent reply other threads:[~2009-10-15 7:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-13 4:49 [RFC][PATCH 0/8] memcg: recharge at task move (Oct13) Daisuke Nishimura
2009-10-13 4:50 ` [RFC][PATCH 1/8] cgroup: introduce cancel_attach() Daisuke Nishimura
2009-10-15 7:37 ` Paul Menage [this message]
2009-10-15 8:50 ` Paul Menage
2009-10-15 11:08 ` Daisuke Nishimura
2009-10-13 4:51 ` [RFC][PATCH 2/8] memcg: cleanup mem_cgroup_move_parent() Daisuke Nishimura
2009-10-13 4:52 ` [RFC][PATCH 3/8] memcg: move memcg_tasklist mutex Daisuke Nishimura
2009-10-13 4:53 ` [RFC][PATCH 4/8] memcg: add interface to recharge at task move Daisuke Nishimura
2009-10-13 4:55 ` [RFC][PATCH 5/8] memcg: recharge charges of mapped page Daisuke Nishimura
2009-10-13 4:56 ` [RFC][PATCH 6/8] memcg: avoid oom during recharge at task move Daisuke Nishimura
2009-10-13 4:57 ` [RFC][PATCH 7/8] memcg: recharge charges of anonymous swap Daisuke Nishimura
2009-10-13 4:58 ` [RFC][PATCH 8/8] memcg: recharge charges of shmem swap Daisuke Nishimura
2009-10-14 7:03 ` [RFC][PATCH 0/8] memcg: recharge at task move (Oct13) KAMEZAWA Hiroyuki
2009-10-15 0:27 ` Daisuke Nishimura
-- strict thread matches above, loose matches on Subject: below --
2009-09-17 2:23 [RFC][EXPERIMENTAL][PATCH 0/8] memcg: migrate charge at task move Daisuke Nishimura
2009-09-17 7:01 ` Daisuke Nishimura
2009-09-24 5:42 ` [RFC][PATCH 0/8] memcg: migrate charge at task move (24/Sep) Daisuke Nishimura
2009-09-24 5:43 ` [RFC][PATCH 1/8] cgroup: introduce cancel_attach() Daisuke Nishimura
2009-09-24 6:33 ` KAMEZAWA Hiroyuki
2009-09-24 23:39 ` Daisuke Nishimura
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