From: Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: axboe-tSWWG44O7X1aa/9Udqfwiw@public.gmane.org,
ctalbott-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
rni-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 4/4] blkcg: use radix tree to index blkgs from blkcg
Date: Fri, 20 Apr 2012 13:26:39 -0400 [thread overview]
Message-ID: <20120420172639.GM22419@redhat.com> (raw)
In-Reply-To: <1334878164-24788-5-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
On Thu, Apr 19, 2012 at 04:29:24PM -0700, Tejun Heo wrote:
> blkg lookup is currently performed by traversing linked list anchored
> at blkcg->blkg_list. This is very unscalable and with blk-throttle
> enabled and enough request queues on the system, this can get very
> ugly quickly (blk-throttle performs look up on every bio submission).
>
> This patch makes blkcg use radix tree to index blkgs combined with
> simple last-looked-up hint. This is mostly identical to how icqs are
> indexed from ioc.
>
> Note that because __blkg_lookup() may be invoked without holding queue
> lock, hint is only updated from __blkg_lookup_create(). Due to cfq's
> cfqq caching, this makes hint updates overly lazy. This will be
> improved with scheduled blkcg aware request allocation.
>
> Signed-off-by: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
> Cc: Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Nice to see radix tree lookup and caching hint. Helps with scalability.
Acked-by: Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Vivek
WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com,
cgroups@vger.kernel.org, containers@lists.linux-foundation.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/4] blkcg: use radix tree to index blkgs from blkcg
Date: Fri, 20 Apr 2012 13:26:39 -0400 [thread overview]
Message-ID: <20120420172639.GM22419@redhat.com> (raw)
In-Reply-To: <1334878164-24788-5-git-send-email-tj@kernel.org>
On Thu, Apr 19, 2012 at 04:29:24PM -0700, Tejun Heo wrote:
> blkg lookup is currently performed by traversing linked list anchored
> at blkcg->blkg_list. This is very unscalable and with blk-throttle
> enabled and enough request queues on the system, this can get very
> ugly quickly (blk-throttle performs look up on every bio submission).
>
> This patch makes blkcg use radix tree to index blkgs combined with
> simple last-looked-up hint. This is mostly identical to how icqs are
> indexed from ioc.
>
> Note that because __blkg_lookup() may be invoked without holding queue
> lock, hint is only updated from __blkg_lookup_create(). Due to cfq's
> cfqq caching, this makes hint updates overly lazy. This will be
> improved with scheduled blkcg aware request allocation.
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Vivek Goyal <vgoyal@redhat.com>
Nice to see radix tree lookup and caching hint. Helps with scalability.
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Vivek
next prev parent reply other threads:[~2012-04-20 17:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-19 23:29 [PATCHSET] block: fixes for long standing issues Tejun Heo
2012-04-19 23:29 ` Tejun Heo
[not found] ` <1334878164-24788-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-04-19 23:29 ` [PATCH 1/4] block: collapse blk_alloc_request() into get_request() Tejun Heo
2012-04-19 23:29 ` Tejun Heo
2012-04-19 23:29 ` Tejun Heo
2012-04-19 23:29 ` [PATCH 2/4] block: fix elvpriv allocation failure handling Tejun Heo
2012-04-19 23:29 ` Tejun Heo
2012-04-19 23:29 ` Tejun Heo
2012-04-19 23:29 ` [PATCH 3/4] blkcg: fix blkcg->css ref leak in __blkg_lookup_create() Tejun Heo
2012-04-19 23:29 ` Tejun Heo
2012-04-19 23:29 ` [PATCH 4/4] blkcg: use radix tree to index blkgs from blkcg Tejun Heo
2012-04-20 8:10 ` [PATCHSET] block: fixes for long standing issues Jens Axboe
2012-04-20 8:10 ` Jens Axboe
2012-04-19 23:29 ` [PATCH 4/4] blkcg: use radix tree to index blkgs from blkcg Tejun Heo
[not found] ` <1334878164-24788-5-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-04-20 17:26 ` Vivek Goyal
2012-04-20 17:26 ` Vivek Goyal [this message]
2012-04-20 17:26 ` Vivek Goyal
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