From: Anton Blanchard <anton@samba.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: yuyang.du@intel.com, Brian Norris <computersforpeace@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Paul Turner <pjt@google.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
Yuanhan Liu <yuanhan.liu@linux.intel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Benjamin Segall <bsegall@google.com>,
ppc-dev <linuxppc-dev@lists.ozlabs.org>,
Ingo Molnar <mingo@redhat.com>,
sp@datera.io, Daniel J Blueman <daniel@numascale.com>,
Tejun Heo <tj@kernel.org>,
subbaram@codeaurora.org,
Andrew Morton <akpm@linux-foundation.org>,
Wu Fengguang <fengguang.wu@intel.com>,
lkp@01.org, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] kthread: kthread_bind fails to enforce CPU affinity (fixes kernel BUG at kernel/smpboot.c:134!)
Date: Mon, 8 Dec 2014 15:46:38 +1100 [thread overview]
Message-ID: <20141208154638.37c1ec18@kryten> (raw)
In-Reply-To: <CA+55aFw6gMN5VxONPo9xtJA_+p2iLArSaK-m_4vDL+L07Z6vuA@mail.gmail.com>
Hi Linus,
> The __set_task_cpu() function does various other things too:
>
> set_task_rq(p, cpu);
> #ifdef CONFIG_SMP
> /*
> * After ->cpu is set up to a new value, task_rq_lock(p, ...)
> can be
> * successfuly executed on another CPU. We must ensure that
> updates of
> * per-task data have been completed by this moment.
> */
> smp_wmb();
> task_thread_info(p)->cpu = cpu;
> p->wake_cpu = cpu;
> #endif
>
> which makes me worry about just setting the thread_info->cpu value.
> That set_task_rq() initializes various group scheduling things, an
> dthat whole "wake_cpu" thing seems relevant too.
Yeah, I would definitely like the scheduler guys to weigh in on this,
especially considering how difficult it can be to hit.
Anton
next prev parent reply other threads:[~2014-12-08 4:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-08 3:27 [PATCH] kthread: kthread_bind fails to enforce CPU affinity (fixes kernel BUG at kernel/smpboot.c:134!) Anton Blanchard
2014-12-08 4:28 ` Linus Torvalds
2014-12-08 4:46 ` Anton Blanchard [this message]
2014-12-08 8:34 ` Ingo Molnar
2014-12-08 10:18 ` Anton Blanchard
2014-12-08 23:58 ` [PATCH] powerpc: secondary CPUs signal to master before setting active and online " Anton Blanchard
2014-12-09 20:54 ` Linus Torvalds
2014-12-10 14:08 ` Thomas Gleixner
2014-12-10 23:06 ` Michael Ellerman
2014-12-08 13:54 ` [PATCH] kthread: kthread_bind fails to enforce CPU affinity " Steven Rostedt
2014-12-09 2:24 ` Lai Jiangshan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20141208154638.37c1ec18@kryten \
--to=anton@samba.org \
--cc=akpm@linux-foundation.org \
--cc=bsegall@google.com \
--cc=computersforpeace@gmail.com \
--cc=daniel@numascale.com \
--cc=fengguang.wu@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=lkp@01.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=rafael.j.wysocki@intel.com \
--cc=rostedt@goodmis.org \
--cc=sp@datera.io \
--cc=subbaram@codeaurora.org \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=yuanhan.liu@linux.intel.com \
--cc=yuyang.du@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).