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From: Yong Zhang <yong.zhang0@gmail.com>
To: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Don Zickus <dzickus@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog
Date: Tue, 17 Aug 2010 20:48:39 +0800	[thread overview]
Message-ID: <20100817124839.GA2838@zhy> (raw)
In-Reply-To: <20100817102819.GC12022@swordfish.minsk.epam.com>

On Tue, Aug 17, 2010 at 01:28:19PM +0300, Sergey Senozhatsky wrote:
> > So preempt_disable() is redundant here.
> >
> 
> Shouldn't we be for sure not preepmtible when calling __raw_get_cpu_var?

IMHO, it's the caller's responsibility.

> 
> preempt_disable is reduntant here because current_thread_info()->cpu is 
> atomic and we just don't want preempt_(enable|disable) overhead?

Yep.

Thanks,
Yong

  reply	other threads:[~2010-08-17 12:48 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-13 10:21 fix BUG: using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog Sergey Senozhatsky
2010-08-16  8:22 ` Peter Zijlstra
2010-08-16 13:34   ` Don Zickus
2010-08-16 13:46     ` Peter Zijlstra
2010-08-16 14:08       ` [PATCH] fix BUG " Sergey Senozhatsky
2010-08-16 14:30         ` Don Zickus
2010-08-17  4:27           ` Yong Zhang
2010-08-17  2:59         ` Frederic Weisbecker
2010-08-17  3:16           ` Yong Zhang
2010-08-17  8:39             ` Sergey Senozhatsky
2010-08-17  9:05               ` Yong Zhang
2010-08-17  9:24                 ` Sergey Senozhatsky
2010-08-17  9:37                   ` Yong Zhang
2010-08-17 10:28                     ` Sergey Senozhatsky
2010-08-17 12:48                       ` Yong Zhang [this message]
2010-08-17 10:39                     ` Sergey Senozhatsky
2010-08-17 12:56                       ` Yong Zhang
2010-08-17 13:13                       ` Don Zickus
2010-08-18  2:48                         ` Frederic Weisbecker
2010-08-18 20:01                           ` Andrew Morton
2010-08-19  2:27                             ` Don Zickus
2010-08-20  2:57                             ` Don Zickus
2010-08-20  3:42                               ` Andrew Morton
2010-08-20 12:34                                 ` Don Zickus
2010-08-26 17:17                                 ` acpi_os_stall() and touch_nmi_watchdog() (was Re: [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog) Len Brown
2010-08-20 15:02                               ` [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog Yong Zhang
2010-08-26 10:14                               ` Maxim Levitsky
2010-08-26 14:40                                 ` Don Zickus
2010-08-17  7:56           ` [PATCH] fix BUG using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog (v2) Sergey Senozhatsky
2010-08-16 14:12       ` fix BUG: using smp_processor_id() in touch_nmi_watchdog and touch_softlockup_watchdog Don Zickus
2010-08-16 14:29         ` Peter Zijlstra
2010-08-16 14:06     ` Yong Zhang
2010-08-18 19:33 ` Andrew Morton
2010-08-18 21:44   ` Cyrill Gorcunov
2010-09-22  9:00   ` [PATCH] avoid second smp_processor_id() call in __touch_watchdog Sergey Senozhatsky
2010-09-22 14:41     ` Don Zickus
2010-09-22 16:27     ` Frederic Weisbecker
2010-09-22 16:39       ` Peter Zijlstra
2010-09-22 16:47         ` Frederic Weisbecker
2010-09-24 19:34     ` Don Zickus
2010-09-25 17:43       ` Sergey Senozhatsky

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