From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Andrzej Siewior Subject: Re: [PATCH RT 26/39] scheduling while atomic in cgroup code Date: Wed, 18 Mar 2015 09:37:02 +0100 Message-ID: <5509392E.8000701@linutronix.de> References: <20150312191307.081068717@goodmis.org> <20150312191411.381735145@goodmis.org> <20150317201010.GB26043@windriver.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: linux-kernel@vger.kernel.org, linux-rt-users , Thomas Gleixner , Carsten Emde , John Kacur , stable-rt@vger.kernel.org, Nikita Yushchenko , Mike Galbraith To: Paul Gortmaker , Steven Rostedt Return-path: In-Reply-To: <20150317201010.GB26043@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On 03/17/2015 09:10 PM, Paul Gortmaker wrote: > [[PATCH RT 26/39] scheduling while atomic in cgroup code] On 12/03/2015 (Thu 15:13) Steven Rostedt wrote: > >> 3.14.34-rt32-rc1 stable review patch. >> If anyone has any objections, please let me know. >> >> ------------------ >> >> From: Mike Galbraith >> >> mm, memcg: make refill_stock() use get_cpu_light() > > This looks like only 1/2 of Mike's original patch: > > https://lkml.org/lkml/2014/6/21/11 > > I suspect that is because 3.18 could only use 1/2 of it, and based on > the SOB lines, this is backported from 3.18. no. I didn't take the upper chunk because get_cpu_var() does only a preempt_disable() and in that section there is not point of preemption or a lock in involved. So it is fine the way it is. The suggest change does a migrate_disable() which is a little more code. The lower part (the chunk I applied) invokes drain_stock() and that is where the sleeping-while-atomic warning came from. So is the upper half really required and if so, why? > The other half applies to 3.14 -- testing in progress; not sure about > the 3.10-rt and earlier.... > > P. Sebastian