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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Ben Segall <bsegall@google.com>
Cc: Xunlei Pang <xlpang@linux.alibaba.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] sched/fair: sync expires_seq in distribute_cfs_runtime()
Date: Fri, 3 Aug 2018 14:56:03 -0700	[thread overview]
Message-ID: <CAM_iQpUA8mn_kTGsJJDKBH0gF1tErg3RnuG0bYd6amH2T_YLHw@mail.gmail.com> (raw)
In-Reply-To: <xm267ela80qn.fsf@bsegall-linux.svl.corp.google.com>

On Wed, Aug 1, 2018 at 10:17 AM <bsegall@google.com> wrote:
> Yes, in practice what's actually going to happen is that the
> runtime_remaining will be put to 1 by distribute, the cfs_rq will be
> unthrottled, and then when it runs it will go negative immediately and
> hit the negative check in expires, so expires_seq being wrong will not
> actually matter. In addition, the worst thing that will happen if one of
> the account_cfs_rq_runtime(cfs_rq, 0) paths is hit first is that it will
> lose 1ns of quota, which also doesn't really matter.

Ah, I see.

Thanks!

      reply	other threads:[~2018-08-03 21:55 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-28  0:24 [PATCH] sched/fair: sync expires_seq in distribute_cfs_runtime() Cong Wang
2018-07-30  5:28 ` Xunlei Pang
2018-07-30 17:32   ` bsegall
2018-07-30 17:55   ` Cong Wang
2018-07-31 14:58     ` Xunlei Pang
2018-07-31 17:13       ` bsegall
2018-07-31 20:55         ` Cong Wang
2018-08-01  3:24           ` Xunlei Pang
2018-08-03 18:57             ` Cong Wang
2018-08-01 17:17           ` bsegall
2018-08-03 21:56             ` Cong Wang [this message]

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