From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Shaohua Li <shaohua.li@intel.com>
Cc: Nigel Cunningham <ncunningham@cyclades.com>,
Andrew Morton <akpm@osdl.org>, Linus Torvalds <torvalds@osdl.org>,
Zwane Mwaikambo <zwane@arm.linux.org.uk>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Ingo Molnar <mingo@elte.hu>
Subject: Re: PATCH: Fix race in cpu_down (hotplug cpu)
Date: Mon, 19 Sep 2005 11:27:15 +0530 [thread overview]
Message-ID: <20050919055715.GE8653@in.ibm.com> (raw)
In-Reply-To: <1127107887.3958.9.camel@linux-hp.sh.intel.com>
On Mon, Sep 19, 2005 at 01:31:27PM +0800, Shaohua Li wrote:
> A CPU is idle and then is preempted and starting offline CPU. After
> calling stop_machine_run, the CPU goes into idle and it will resume last
> idle loop. If the CPU is broken at specific point, then the CPU will
> continue executing previous idle and have no chance to call play_dead.
Ok, that makes sense. Nigel, could you confirm which idle routine you are
using?
> Am I missing anything? Nigel's patch seems can fix the situation for
> mwait_idle and poll_idle but can't fix for default_idle in i386 to me.
I would say the right fix here is for poll_idle and mwait_idle (& similar
other idle routines) to monitor 'cpu_offline' flag in addition to need_resched
flag, rather than what Nigel has suggested.
--
Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
next prev parent reply other threads:[~2005-09-19 5:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-19 4:48 PATCH: Fix race in cpu_down (hotplug cpu) Li, Shaohua
2005-09-19 5:10 ` Srivatsa Vaddagiri
2005-09-19 5:31 ` Shaohua Li
2005-09-19 5:57 ` Srivatsa Vaddagiri [this message]
2005-09-19 6:11 ` Nigel Cunningham
2005-09-19 6:23 ` Srivatsa Vaddagiri
2005-09-19 6:29 ` Nick Piggin
2005-09-19 7:00 ` Srivatsa Vaddagiri
2005-09-19 6:31 ` Nigel Cunningham
2005-09-19 7:09 ` Srivatsa Vaddagiri
2005-09-19 6:37 ` Shaohua Li
2005-09-19 6:36 ` Nick Piggin
2005-09-19 6:54 ` Nigel Cunningham
2005-09-19 7:12 ` Shaohua Li
2005-09-19 7:22 ` Nick Piggin
2005-09-19 7:28 ` Ingo Molnar
2005-09-19 7:37 ` Nick Piggin
2005-09-19 22:55 ` Nigel Cunningham
2005-09-20 4:41 ` Srivatsa Vaddagiri
2005-09-19 7:07 ` Srivatsa Vaddagiri
2005-09-19 5:23 ` Nigel Cunningham
2005-09-19 5:28 ` Srivatsa Vaddagiri
2005-09-19 5:35 ` Nigel Cunningham
2005-09-19 7:43 ` Where do packets sent to 255.255.255.255 go? Wei-Che, Hsu
-- strict thread matches above, loose matches on Subject: below --
2005-09-19 3:28 PATCH: Fix race in cpu_down (hotplug cpu) Nigel Cunningham
2005-09-19 4:22 ` Srivatsa Vaddagiri
2005-09-19 3:15 Nigel Cunningham
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