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From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Will Deacon <will@kernel.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	paulmck <paulmck@linux.ibm.com>, Ingo Molnar <mingo@kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Russell King, ARM Linux" <linux@armlinux.org.uk>,
	Chris Metcalf <cmetcalf@ezchip.com>, Chris Lameter <cl@linux.com>,
	Kirill Tkhai <tkhai@yandex.ru>, Mike Galbraith <efault@gmx.de>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC PATCH 4/4] Fix: sched/membarrier: p->mm->membarrier_state racy load (v2)
Date: Thu, 19 Sep 2019 13:33:09 -0400 (EDT)	[thread overview]
Message-ID: <1285036359.17389.1568914389549.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <20190919162611.wizldpybn3qd5cik@willie-the-truck>

----- On Sep 19, 2019, at 12:26 PM, Will Deacon will@kernel.org wrote:

[...]
>> 
>> The current wording from membarrier(2) is:
>> 
>>               The  "expedited" commands complete faster than the non-expedited
>>               ones; they never block, but have the downside of  causing  extra
>>               overhead.
>> 
>> We could simply remove the "; they never block" part then ?
> 
> I think so, yes. That or, "; they do not voluntarily block" or something
> like that. Maybe look at other man pages for inspiration ;)

OK, let's tackle the man-pages part after the fix reaches mainline though.

[...]
> 
> I reckon you'll be fine using GFP_KERNEL and returning -ENOMEM on allocation
> failure. This shouldn't happen in practice and it removes the fallback
> path.

Works for me! I'll prepare an updated patchset.

Thanks,

Mathieu


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com

  reply	other threads:[~2019-09-19 17:33 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-06  3:12 [RFC PATCH 0/4] Membarrier fixes/cleanups Mathieu Desnoyers
2019-09-06  3:12 ` [RFC PATCH 1/4] Fix: sched/membarrier: private expedited registration check Mathieu Desnoyers
2019-09-06  3:12 ` [RFC PATCH 2/4] Cleanup: sched/membarrier: remove redundant check Mathieu Desnoyers
2019-09-06  3:12 ` [RFC PATCH 3/4] Cleanup: sched/membarrier: only sync_core before usermode for same mm Mathieu Desnoyers
2019-09-06  7:41   ` Peter Zijlstra
2019-09-06 13:40     ` Mathieu Desnoyers
2019-09-06  3:13 ` [RFC PATCH 4/4] Fix: sched/membarrier: p->mm->membarrier_state racy load Mathieu Desnoyers
2019-09-06  8:23   ` Peter Zijlstra
2019-09-08 13:49     ` [RFC PATCH 4/4] Fix: sched/membarrier: p->mm->membarrier_state racy load (v2) Mathieu Desnoyers
2019-09-08 16:51       ` Linus Torvalds
2019-09-10  9:48         ` Mathieu Desnoyers
2019-09-12 13:48           ` Will Deacon
2019-09-12 14:24             ` Linus Torvalds
2019-09-12 15:47               ` Will Deacon
2019-09-13 14:22                 ` Mathieu Desnoyers
2019-09-19 16:26                   ` Will Deacon
2019-09-19 17:33                     ` Mathieu Desnoyers [this message]
2019-09-09 11:00       ` Oleg Nesterov
2019-09-13 15:20         ` Mathieu Desnoyers
2019-09-13 16:04           ` Oleg Nesterov
2019-09-13 17:07             ` Mathieu Desnoyers

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