From: Ingo Molnar <mingo@elte.hu>
To: Dongdong Deng <dongdong.deng@windriver.com>
Cc: dzickus@redhat.com, peterz@infradead.org, tglx@linutronix.de,
mingo@redhat.com, hpa@zytor.com, x86@kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: avoid calling arch_trigger_all_cpu_backtrace() at the same time on SMP
Date: Thu, 11 Nov 2010 10:23:01 +0100 [thread overview]
Message-ID: <20101111092301.GD18789@elte.hu> (raw)
In-Reply-To: <1289442042-2515-1-git-send-email-dongdong.deng@windriver.com>
* Dongdong Deng <dongdong.deng@windriver.com> wrote:
> +static int backtrace_flag;
> + if (cmpxchg(&backtrace_flag, 0, 1) != 0)
Sorry to be a PITA, but i asked for test_and_set() because that's the simplest
primitive. cmpxchg() semantics is not nearly as obvious and people regularly get it
wrong :-/
Also, variables that cmpxchg or test_and_set operates on need to be long, not int.
Ingo
next prev parent reply other threads:[~2010-11-11 9:23 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-11 2:20 [PATCH] x86: avoid calling arch_trigger_all_cpu_backtrace() at the same time on SMP Dongdong Deng
2010-11-11 9:23 ` Ingo Molnar [this message]
2010-11-11 9:51 ` DDD
2010-11-11 10:01 ` Ingo Molnar
2010-11-11 11:00 ` DDD
2010-11-11 9:51 ` Eric Dumazet
2010-11-11 9:57 ` Ingo Molnar
-- strict thread matches above, loose matches on Subject: below --
2010-11-02 18:16 Don Zickus
2010-11-10 7:43 ` Ingo Molnar
2010-11-10 8:35 ` DDD
2010-11-10 8:39 ` Ingo Molnar
2010-10-11 10:31 Dongdong Deng
2010-10-18 11:00 ` DDD
2010-10-18 18:03 ` Don Zickus
2010-10-21 5:17 ` DDD
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