From: Vivek Goyal <vgoyal@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 05/12] blkcg: update blkg get functions take blkio_cgroup as parameter
Date: Thu, 19 Jan 2012 06:21:02 -0500 [thread overview]
Message-ID: <20120119112102.GD2649@redhat.com> (raw)
In-Reply-To: <1326935490-11827-6-git-send-email-tj@kernel.org>
On Wed, Jan 18, 2012 at 05:11:23PM -0800, Tejun Heo wrote:
[..]
> -static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
> +static struct throtl_grp *throtl_get_tg(struct throtl_data *td,
> + struct blkio_cgroup *blkcg)
> {
> struct throtl_grp *tg = NULL, *__tg = NULL;
> - struct blkio_cgroup *blkcg;
> struct request_queue *q = td->queue;
>
> /* no throttling for dead queue */
> if (unlikely(blk_queue_dead(q)))
> return NULL;
>
> - blkcg = task_blkio_cgroup(current);
> tg = throtl_find_tg(td, blkcg);
> if (tg)
> return tg;
>
> + if (!css_tryget(&blkcg->css))
> + return NULL;
> +
This reference is to make sure that blkcg does not go away while we drop
the rcu lock and do the group allocation?
Thanks
Vivek
next prev parent reply other threads:[~2012-01-19 11:21 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-19 1:11 [PATCHSET] blkcg: kill policy node and blkg->dev Tejun Heo
2012-01-19 1:11 ` [PATCH 01/12] blkcg: obtaining blkg should be enclosed inside rcu_read_lock() Tejun Heo
2012-01-19 10:07 ` Vivek Goyal
2012-01-19 15:39 ` Tejun Heo
2012-01-19 15:54 ` Vivek Goyal
2012-01-19 15:58 ` Tejun Heo
2012-01-19 1:11 ` [PATCH 02/12] cfq: don't register propio policy if !CONFIG_CFQ_GROUP_IOSCHED Tejun Heo
2012-01-19 10:11 ` Vivek Goyal
2012-01-19 1:11 ` [PATCH 03/12] elevator: clear auxiliary data earlier during elevator switch Tejun Heo
2012-01-19 1:11 ` [PATCH 04/12] elevator: make elevator_init_fn() return 0/-errno Tejun Heo
2012-01-19 11:11 ` Vivek Goyal
2012-01-19 15:44 ` Tejun Heo
2012-01-19 1:11 ` [PATCH 05/12] blkcg: update blkg get functions take blkio_cgroup as parameter Tejun Heo
2012-01-19 11:21 ` Vivek Goyal [this message]
2012-01-19 15:45 ` Tejun Heo
2012-01-19 1:11 ` [PATCH 06/12] blkcg: use q and plid instead of opaque void * for blkio_group association Tejun Heo
2012-01-19 14:04 ` Vivek Goyal
2012-01-19 15:55 ` Tejun Heo
2012-01-19 16:16 ` Vivek Goyal
2012-01-19 16:25 ` Tejun Heo
2012-01-19 16:42 ` Tejun Heo
2012-01-19 1:11 ` [PATCH 07/12] blkcg: add blkio_policy[] array and allow one policy per policy ID Tejun Heo
2012-01-19 1:11 ` [PATCH 08/12] blkcg: use the usual get blkg path for root blkio_group Tejun Heo
2012-01-19 14:41 ` Vivek Goyal
2012-01-19 16:17 ` Tejun Heo
2012-01-19 1:11 ` [PATCH 09/12] blkcg: factor out blkio_group creation Tejun Heo
2012-01-19 1:11 ` [PATCH 10/12] blkcg: don't allow or retain configuration of missing devices Tejun Heo
2012-01-19 1:11 ` [PATCH 11/12] blkcg: kill blkio_policy_node Tejun Heo
2012-01-19 20:32 ` Vivek Goyal
2012-01-19 22:03 ` Tejun Heo
2012-01-19 22:30 ` Vivek Goyal
2012-01-19 1:11 ` [PATCH 12/12] blkcg: kill the mind-bending blkg->dev Tejun Heo
2012-01-19 15:49 ` Vivek Goyal
2012-01-19 16:30 ` Tejun Heo
2012-01-19 16:46 ` Vivek Goyal
2012-01-19 1:18 ` [PATCHSET] blkcg: kill policy node and blkg->dev Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120119112102.GD2649@redhat.com \
--to=vgoyal@redhat.com \
--cc=axboe@kernel.dk \
--cc=ctalbott@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rni@google.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).