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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 08/17] blkcg: shoot down blkio_groups on elevator switch
Date: Mon, 23 Jan 2012 10:20:55 -0500	[thread overview]
Message-ID: <20120123152055.GD25986@redhat.com> (raw)
In-Reply-To: <1327202725-3383-9-git-send-email-tj@kernel.org>

On Sat, Jan 21, 2012 at 07:25:16PM -0800, Tejun Heo wrote:

[..]
> diff --git a/block/elevator.c b/block/elevator.c
> index 078a491..5e371e4 100644
> --- a/block/elevator.c
> +++ b/block/elevator.c
> @@ -38,6 +38,7 @@
>  #include <trace/events/block.h>
>  
>  #include "blk.h"
> +#include "blk-cgroup.h"
>  
>  static DEFINE_SPINLOCK(elv_list_lock);
>  static LIST_HEAD(elv_list);
> @@ -939,6 +940,7 @@ static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
>  
>  	spin_lock_irq(q->queue_lock);
>  	ioc_clear_queue(q);
> +	blkcg_clear_queue(q);

What happens to per device rules (per device weight and per device
throttling rules)? IIUC, in new scheme of things, upon elevator switch
these rules will be gone.

I can understand per device weight rules disappearing but what about 
throttling rules. They are independent of IO scheduler and change of
io scheduler should not cause per device throttling rules to get lost.

This just gets worse if elevator switch fails and we fall back to old
elevator. But now we have lost of the rules as rules were part of
blkg.conf and old groups are gone.

Thanks
Vivek

  reply	other threads:[~2012-01-23 15:21 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 [this message]
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
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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