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,
Lennart Poettering <mzxreary@0pointer.de>
Subject: Re: [PATCH 08/17] blkcg: shoot down blkio_groups on elevator switch
Date: Mon, 23 Jan 2012 11:33:35 -0800 [thread overview]
Message-ID: <20120123193335.GK12652@google.com> (raw)
In-Reply-To: <20120123184336.GI12652@google.com>
On Mon, Jan 23, 2012 at 10:43:36AM -0800, Tejun Heo wrote:
> Yeah, this is much more arguable. I don't think it would be too
> complex to keep per-policy granularity even w/ unified blkg managed by
> blkcg core (we'll just need to point to separately allocated
> per-policy data from the unified blkg and clear them selectively).
> I'm just not convinced of its necessity. With initial config out of
> the way, elvs and blkcg policies don't get molested all that often.
>
> I'll see how complex it actually gets. If it isn't too much
> complexity, yeah, why not...
Hmmm... while this isn't terribly complex, it involves considerable
amount of churn as core layer doesn't currently know what policies are
bound to which queues how - we'll have to add some part of that before
shootdown change, use it there, and then later replace it with proper
per-queue thing. The conversion is already painful enough without
adding another chunk to juggle around. Given that clearing all on pol
change isn't too crazy, how about the following?
* For now, clear unconditionally on pol/elv change.
* But structure things such that policy specific data are allocated
separately and on pol/elv change only those policy specific part is
flushed.
* Later, if deemed necessary, make the clearing of pol-specific part
selective.
--
tejun
next prev parent reply other threads:[~2012-01-23 19:33 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-22 3:25 [PATCHSET] blkcg: kill policy node and blkg->dev, take#2 Tejun Heo
2012-01-22 3:25 ` [PATCH 01/17] blkcg: make CONFIG_BLK_CGROUP bool Tejun Heo
2012-01-23 15:00 ` Vivek Goyal
2012-01-23 15:34 ` Tejun Heo
2012-01-22 3:25 ` [PATCH 02/17] cfq: don't register propio policy if !CONFIG_CFQ_GROUP_IOSCHED Tejun Heo
2012-01-22 3:25 ` [PATCH 03/17] elevator: clear auxiliary data earlier during elevator switch Tejun Heo
2012-01-22 3:25 ` [PATCH 04/17] elevator: make elevator_init_fn() return 0/-errno Tejun Heo
2012-01-22 3:25 ` [PATCH 05/17] block: implement blk_queue_bypass_start/end() Tejun Heo
2012-01-22 3:25 ` [PATCH 06/17] block: extend queue bypassing to cover blkcg policies Tejun Heo
2012-01-22 3:25 ` [PATCH 07/17] blkcg: make blkio_list_lock irq-safe Tejun Heo
2012-01-22 3:25 ` [PATCH 08/17] blkcg: shoot down blkio_groups on elevator switch Tejun Heo
2012-01-23 15:20 ` Vivek Goyal
2012-01-23 15:36 ` Vivek Goyal
2012-01-23 15:49 ` Tejun Heo
2012-01-23 15:39 ` Tejun Heo
2012-01-23 15:52 ` Vivek Goyal
2012-01-23 15:57 ` Tejun Heo
2012-01-23 16:10 ` Vivek Goyal
2012-01-23 16:13 ` Vivek Goyal
2012-01-23 16:20 ` Tejun Heo
2012-01-23 16:28 ` Vivek Goyal
2012-01-23 16:32 ` Tejun Heo
2012-01-23 16:16 ` Tejun Heo
2012-01-23 16:25 ` Vivek Goyal
2012-01-23 17:10 ` Tejun Heo
2012-01-23 18:27 ` Vivek Goyal
2012-01-23 18:43 ` Tejun Heo
2012-01-23 19:33 ` Tejun Heo [this message]
2012-01-23 19:57 ` Vivek Goyal
2012-01-23 20:33 ` Tejun Heo
2012-01-23 20:43 ` Lennart Poettering
2012-01-23 20:47 ` Tejun Heo
2012-01-23 21:03 ` Vivek Goyal
2012-01-23 20:40 ` Lennart Poettering
2012-01-23 18:32 ` Vivek Goyal
2012-01-23 18:51 ` Tejun Heo
2012-01-22 3:25 ` [PATCH 09/17] blkcg: move rcu_read_lock() outside of blkio_group get functions Tejun Heo
2012-01-22 3:25 ` [PATCH 10/17] blkcg: update blkg get functions take blkio_cgroup as parameter Tejun Heo
2012-01-22 3:25 ` [PATCH 11/17] blkcg: use q and plid instead of opaque void * for blkio_group association Tejun Heo
2012-01-22 3:25 ` [PATCH 12/17] blkcg: add blkio_policy[] array and allow one policy per policy ID Tejun Heo
2012-01-22 3:25 ` [PATCH 13/17] blkcg: use the usual get blkg path for root blkio_group Tejun Heo
2012-01-22 3:25 ` [PATCH 14/17] blkcg: factor out blkio_group creation Tejun Heo
2012-01-22 3:25 ` [PATCH 15/17] blkcg: don't allow or retain configuration of missing devices Tejun Heo
2012-01-22 3:25 ` [PATCH 16/17] blkcg: kill blkio_policy_node Tejun Heo
2012-01-22 3:25 ` [PATCH 17/17] blkcg: kill the mind-bending blkg->dev Tejun Heo
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