From: Tejun Heo <tj@kernel.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: lizefan@huawei.com, axboe@kernel.dk,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, ctalbott@google.com,
rni@google.com
Subject: Re: [PATCH 06/12] cfq-iosched: implement cfq_group->nr_active and ->level_weight
Date: Mon, 17 Dec 2012 13:15:17 -0800 [thread overview]
Message-ID: <20121217211517.GC1844@htj.dyndns.org> (raw)
In-Reply-To: <20121217204609.GH7235@redhat.com>
Hello, Vivek.
On Mon, Dec 17, 2012 at 03:46:09PM -0500, Vivek Goyal wrote:
> On Fri, Dec 14, 2012 at 02:41:19PM -0800, Tejun Heo wrote:
> > To prepare for blkcg hierarchy support, add cfqg->nr_active and
> > ->level_weight. cfqg->nr_active counts the number of active cfqgs at
> > the cfqg's level and ->level_weight is sum of weights of those cfqgs.
> > The level covers itself (cfqg->leaf_weight) and immediate children.
>
> This notion of level is really confusing. If one says "at cfqg's level"
> I immediately associate with cfqg's siblings and not with cfqg's children.
We can explicitly say at children's level but I think it should be
enough to explain it clearly in the comment where the field is
defined.
> I think confusion happens because we are overloading the definition of
> cfqg. It is competing with its siblings at the same time it is competing
> against its child groups (on behalf of its children tasks).
While I agree that part is a bit tricky, I can't think of a much
better way to describe it. Any better ideas?
Thanks.
--
tejun
next prev parent reply other threads:[~2012-12-17 21:15 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-14 22:41 [PATCHSET] block: implement blkcg hierarchy support in cfq Tejun Heo
2012-12-14 22:41 ` [PATCH 01/12] blkcg: fix minor bug in blkg_alloc() Tejun Heo
2012-12-17 19:10 ` Vivek Goyal
2012-12-14 22:41 ` [PATCH 02/12] blkcg: reorganize blkg_lookup_create() and friends Tejun Heo
2012-12-17 19:28 ` Vivek Goyal
2012-12-14 22:41 ` [PATCH 03/12] blkcg: cosmetic updates to blkg_create() Tejun Heo
2012-12-17 19:37 ` Vivek Goyal
2012-12-14 22:41 ` [PATCH 04/12] blkcg: make blkcg_gq's hierarchical Tejun Heo
2012-12-17 20:04 ` Vivek Goyal
2012-12-14 22:41 ` [PATCH 05/12] cfq-iosched: add leaf_weight Tejun Heo
2012-12-14 22:41 ` [PATCH 06/12] cfq-iosched: implement cfq_group->nr_active and ->level_weight Tejun Heo
2012-12-17 20:46 ` Vivek Goyal
2012-12-17 21:15 ` Tejun Heo [this message]
2012-12-17 21:18 ` Vivek Goyal
2012-12-17 21:20 ` Tejun Heo
2012-12-14 22:41 ` [PATCH 07/12] cfq-iosched: implement hierarchy-ready cfq_group charge scaling Tejun Heo
2012-12-17 20:53 ` Vivek Goyal
2012-12-17 21:17 ` Tejun Heo
2012-12-17 21:27 ` Vivek Goyal
2012-12-17 21:33 ` Tejun Heo
2012-12-17 21:49 ` Vivek Goyal
2012-12-17 22:12 ` Tejun Heo
2012-12-14 22:41 ` [PATCH 08/12] cfq-iosched: convert cfq_group_slice() to use cfqg->vfraction Tejun Heo
2012-12-14 22:41 ` [PATCH 09/12] cfq-iosched: enable full blkcg hierarchy support Tejun Heo
2012-12-18 18:40 ` Vivek Goyal
2012-12-18 19:10 ` Tejun Heo
2012-12-18 19:16 ` Vivek Goyal
2012-12-18 19:17 ` Tejun Heo
2012-12-14 22:41 ` [PATCH 10/12] blkcg: add blkg_policy_data->plid Tejun Heo
2012-12-14 22:41 ` [PATCH 11/12] blkcg: implement blkg_prfill_[rw]stat_recursive() Tejun Heo
2012-12-14 22:41 ` [PATCH 12/12] cfq-iosched: add hierarchical cfq_group statistics Tejun Heo
2012-12-18 19:11 ` Vivek Goyal
2012-12-18 19:14 ` Tejun Heo
2012-12-18 19:18 ` Vivek Goyal
2012-12-18 19:21 ` Tejun Heo
2012-12-18 19:26 ` Vivek Goyal
2012-12-17 16:52 ` [PATCHSET] block: implement blkcg hierarchy support in cfq Vivek Goyal
2012-12-17 17:38 ` Tejun Heo
2012-12-17 18:50 ` Vivek Goyal
2012-12-17 18:59 ` Tejun Heo
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