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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 UPDATED 11/11] blkcg: unify blkg's for blkcg policies
Date: Fri, 3 Feb 2012 13:47:19 -0800	[thread overview]
Message-ID: <20120203214719.GE14209@google.com> (raw)
In-Reply-To: <20120203214435.GC12616@redhat.com>

On Fri, Feb 03, 2012 at 04:44:35PM -0500, Vivek Goyal wrote:
> Ok, looks like now it is needed because blkcg lock will just gurantee that
> blkg is around but blkg->pd[plid] can disappear if you are not holding
> blkio_list lock (update_root_blkgs).
> 
> I am wondering if we should take blkcg->lock if blkg is on blkcg list and
> is being modified in place. That way, once we are switching elevator,
> we should be able to shoot down the policy data without taking blkio_list
> lock.

I think it gotta become something per-queue, not global, and if we
make it per-queue, it should be able to live inside queue_lock.

Thanks.

-- 
tejun

  reply	other threads:[~2012-02-03 21:47 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-01 21:19 [PATCHSET] blkcg: unify blkgs for different policies Tejun Heo
2012-02-01 21:19 ` [PATCH 01/11] blkcg: let blkio_group point to blkio_cgroup directly Tejun Heo
2012-02-02 20:03   ` Vivek Goyal
2012-02-02 20:33     ` Tejun Heo
2012-02-02 20:55       ` Vivek Goyal
2012-02-01 21:19 ` [PATCH 02/11] block: relocate elevator initialized test from blk_cleanup_queue() to blk_drain_queue() Tejun Heo
2012-02-02 20:20   ` Vivek Goyal
2012-02-02 20:35     ` Tejun Heo
2012-02-02 20:37       ` Vivek Goyal
2012-02-02 20:38         ` Tejun Heo
2012-02-01 21:19 ` [PATCH 03/11] blkcg: add blkcg_{init|drain|exit}_queue() Tejun Heo
2012-02-01 21:19 ` [PATCH 04/11] blkcg: clear all request_queues on blkcg policy [un]registrations Tejun Heo
2012-02-01 21:19 ` [PATCH 05/11] blkcg: let blkcg core handle policy private data allocation Tejun Heo
2012-02-01 21:19 ` [PATCH 06/11] blkcg: move refcnt to blkcg core Tejun Heo
2012-02-02 22:07   ` Vivek Goyal
2012-02-02 22:11     ` Tejun Heo
2012-02-01 21:19 ` [PATCH 07/11] blkcg: make blkg->pd an array and move configuration and stats into it Tejun Heo
2012-02-01 21:19 ` [PATCH 08/11] blkcg: don't use blkg->plid in stat related functions Tejun Heo
2012-02-01 21:19 ` [PATCH 09/11] blkcg: move per-queue blkg list heads and counters to queue and blkg Tejun Heo
2012-02-02 22:47   ` Vivek Goyal
2012-02-02 22:47     ` Tejun Heo
2012-02-01 21:19 ` [PATCH 10/11] blkcg: let blkcg core manage per-queue blkg list and counter Tejun Heo
2012-02-01 21:19 ` [PATCH 11/11] blkcg: unify blkg's for blkcg policies Tejun Heo
2012-02-02  0:37   ` [PATCH UPDATED " Tejun Heo
2012-02-03 19:41     ` Vivek Goyal
2012-02-03 20:59       ` Tejun Heo
2012-02-03 21:44         ` Vivek Goyal
2012-02-03 21:47           ` Tejun Heo [this message]
2012-02-03 21:53             ` Vivek Goyal
2012-02-03 22:14               ` Tejun Heo
2012-02-03 22:23                 ` Vivek Goyal
2012-02-03 22:28                   ` Tejun Heo
2012-02-03 21:06     ` Vivek Goyal
2012-02-03 21:09       ` Tejun Heo
2012-02-03 21:10         ` Tejun Heo
2012-02-14  1:33     ` [PATCH UPDATED2 " Tejun Heo
2012-02-15 17:02       ` Vivek Goyal
2012-02-16 22:42         ` Tejun Heo
2012-02-02 19:29 ` [PATCHSET] blkcg: unify blkgs for different policies Vivek Goyal
2012-02-02 20:36   ` Tejun Heo
2012-02-02 20:43     ` Vivek Goyal
2012-02-02 20:59       ` Tejun Heo

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