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 08/17] blkcg: shoot down blkio_groups on elevator switch
Date: Mon, 23 Jan 2012 08:16:19 -0800 [thread overview]
Message-ID: <20120123161619.GE12652@google.com> (raw)
In-Reply-To: <20120123161042.GG25986@redhat.com>
On Mon, Jan 23, 2012 at 11:10:42AM -0500, Vivek Goyal wrote:
> This does not work well in hierachical management/scenario. Think that
> a user gets an upper limit of 10MB/s on a device and now user can manage
> its own children groups and divide allocated 10MB/s in children the way
> he wants.
>
> Now if root does the elevator switch, and saves all the rules (including
> user's rules) and then restores back, these can very well race with
> user's scripts of changing rules. If user changed a cgroup device rule
> during elevator switch and after elevator switch root restored back
> old rules, user's new rule will be lost leading to confusion.
It simply doesn't matter. Just declare elvswitch and policy change
reset blkcg configurations. If some people are crazy enough to switch
elevators regularly with full system running and parallel
configuration going on, let them deal with synchronizing their
scripts.
--
tejun
next prev parent reply other threads:[~2012-01-23 16:16 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 [this message]
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
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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