From: Tejun Heo <tj@kernel.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 11/12] blkcg: kill blkio_policy_node
Date: Thu, 19 Jan 2012 14:03:06 -0800 [thread overview]
Message-ID: <20120119220306.GK5198@google.com> (raw)
In-Reply-To: <20120119203225.GA4421@redhat.com>
Hello,
On Thu, Jan 19, 2012 at 03:32:25PM -0500, Vivek Goyal wrote:
> On Wed, Jan 18, 2012 at 05:11:29PM -0800, Tejun Heo wrote:
>
> [..]
> > @@ -1413,14 +1110,10 @@ static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
> > spin_lock_irq(&blkcg->lock);
> > blkcg->weight = (unsigned int)val;
> >
> > - hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
> > - pn = blkio_policy_search_node(blkcg, blkg->dev,
> > - BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
> > - if (pn)
> > - continue;
> > + hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
> > + if (blkg->plid == plid && !blkg->conf.weight)
> > + blkio_update_group_weight(blkg, blkcg->weight);
>
> Tejun,
>
> Why do we check for blkg->conf.weight=0 here. Even if a group already has
> weight and if user has changed the cgroup weight later, that update should
> be propogated to all the groups on all the queues.
Maybe I misread the code but if explicit per-device config exists,
cgroup-wide writes are ignored, no? The original code searches for
matching pn and if it exists, continues without updating.
> Where do we assign default cgroup weight to a blkg upon creation? May be at
> group create time, we just need to copy blkcg->weight to blkg.conf.weight.
We don't. blk->conf.weight is set only on explicit per-device
configuration. It's gonna be removed eventually after config
definition and handling are moved into policies.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-01-19 22:03 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
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 [this message]
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=20120119220306.GK5198@google.com \
--to=tj@kernel.org \
--cc=axboe@kernel.dk \
--cc=ctalbott@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=rni@google.com \
--cc=vgoyal@redhat.com \
/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).