Re: sched/autogroup: race if !sysctl_sched_autogroup_enabled ?

From	Oleg Nesterov <oleg@redhat.com>
Newsgroups	linux.kernel
Subject	Re: sched/autogroup: race if !sysctl_sched_autogroup_enabled ?
Date	2016-11-14 16:20 +0100
Message-ID	<sDrd7-eg-25@gated-at.bofh.it> (permalink)
References	<sBEoa-1rS-29@gated-at.bofh.it> <sBFkd-20O-3@gated-at.bofh.it> <sBXqN-6H1-13@gated-at.bofh.it> <sCnlf-6OQ-15@gated-at.bofh.it> <sD3u9-Wo-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 11/13, Mike Galbraith wrote:
>
> Autogroup never should have had knobs in the first place, and now, Oleg has
> discovered that the dynamic enable/disable capability either has become, or
> perhaps always was racy.

It was always racy afaics, even if sysctl_sched_autogroup_enabled doesn't
change. So this patch is not enough.

But the main reason I dislike it is that I can't backport it ;) rhel7 runs
with sysctl_sched_autogroup_enabled=0 by default, and users actually use
this knob to enable it dynamically.

Mike, et al, sorry for delay. I'll try to finally force myself to write the
comments and the changelog and send 2 (trivial) fixes today.

Oleg.

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Re: sched/autogroup: race if !sysctl_sched_autogroup_enabled ? Mike Galbraith <efault@gmx.de> - 2016-11-13 15:00 +0100
  Re: sched/autogroup: race if !sysctl_sched_autogroup_enabled ? Oleg Nesterov <oleg@redhat.com> - 2016-11-14 16:20 +0100

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