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From: Ingo Molnar <mingo@elte.hu>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dongdong Deng <dongdong.deng@windriver.com>,
	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 10:57:50 +0100	[thread overview]
Message-ID: <20101111095750.GA24558@elte.hu> (raw)
In-Reply-To: <1289469104.17691.1025.camel@edumazet-laptop>


* Eric Dumazet <eric.dumazet@gmail.com> wrote:

> Le jeudi 11 novembre 2010 à 10:23 +0100, Ingo Molnar a écrit :
> 
> > Also, variables that cmpxchg or test_and_set operates on need to be long, not int.
> 
> Hmm, ok for test_and_set(), it operates on a long.
> 
> cmpxchg() is ok on an int AFAIK. If not we have to make some changes :(
> 
> btrfs_orphan_cleanup() for example does this :
> 
> 	if (cmpxchg(&root->orphan_cleanup_state, 0, ORPHAN_CLEANUP_STARTED))
> 		...
> 
> 
> Same in build_ehash_secret() (net/ipv4/af_inet.c)
> 
> 	cmpxchg(&inet_ehash_secret, 0, rnd);

You are right - cmpxchg() auto-detects the word size and thus should work on int 
too.

Thanks,

	Ingo

  reply	other threads:[~2010-11-11  9:58 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
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 [this message]
  -- 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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