From: Tejun Heo <tj@kernel.org>
To: Shaohua Li <shli@kernel.org>
Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org,
kernel-team@fb.com, lizefan@huawei.com, hannes@cmpxchg.org,
cgroups@vger.kernel.org, guro@fb.com
Subject: Re: [PATCH 7/7] blk-throtl: don't throttle the same IO multiple times
Date: Mon, 13 Nov 2017 07:57:45 -0800 [thread overview]
Message-ID: <20171113155745.GI983427@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20171113111348.GF983427@devbig577.frc2.facebook.com>
Hello,
On Mon, Nov 13, 2017 at 03:13:48AM -0800, Tejun Heo wrote:
> You're right. If we wanna take this approach, we need to keep the
> throttled flag while cloning. The clearing part is still correct tho.
> Without that, I get 1/4 bw limit enforced. Hmm... I'm not quite sure
> where that 1/4 is coming from tho. Will investigate more.
Okay, this is because when we spiit, the split bio is the first part
which gets issued and then the orignal bio is wound forward and
requeued. So, for the splits, the original bio is the one which gets
trimmed in the front and requeued, so not clearing BIO_THROTTLED is
enough. I think we should still copy BIO_THROTTLED on clones so that
we don't get suprises w/ other bio drivers.
Thanks.
--
tejun
next prev parent reply other threads:[~2017-11-13 15:57 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-12 22:26 [PATCHSET] blkcg: basic accounting and throttling fixes Tejun Heo
2017-11-12 22:26 ` [PATCH 1/7] blkcg: relocate __blkg_release_rcu() Tejun Heo
2017-11-14 23:12 ` Shaohua Li
2017-11-12 22:26 ` [PATCH 2/7] blkcg: use percpu_ref for blkcg_gq->refcnt Tejun Heo
2017-11-14 23:12 ` Shaohua Li
2017-11-12 22:26 ` [PATCH 3/7] blkcg: associate a request with its blkcg_gq instead of request_list Tejun Heo
2017-11-13 20:15 ` [PATCH v2 " Tejun Heo
2017-11-14 23:17 ` Shaohua Li
2017-11-15 17:11 ` Tejun Heo
2017-11-12 22:26 ` [PATCH 4/7] blkcg: refactor blkcg_gq lookup and creation in blkcg_bio_issue_check() Tejun Heo
2017-11-14 23:18 ` Shaohua Li
2017-11-12 22:26 ` [PATCH 5/7] blkcg: associate blk-mq requests with the matching blkcg_gqs Tejun Heo
2017-11-12 22:26 ` [PATCH 6/7] blkcg: account requests instead of bios for request based request_queues Tejun Heo
2017-11-14 23:23 ` Shaohua Li
2017-11-15 17:18 ` [PATCH v2 " Tejun Heo
2017-11-15 17:19 ` [PATCH " Jens Axboe
2017-11-15 17:22 ` [PATCH v3 " Tejun Heo
2017-11-12 22:26 ` [PATCH 7/7] blk-throtl: don't throttle the same IO multiple times Tejun Heo
2017-11-13 4:07 ` Shaohua Li
2017-11-13 11:13 ` Tejun Heo
2017-11-13 15:57 ` Tejun Heo [this message]
2017-11-13 19:54 ` Shaohua Li
2017-11-13 19:58 ` Tejun Heo
2017-11-13 19:58 ` Shaohua Li
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