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From: Andi Kleen <andi@firstfloor•org>
To: Milton Miller <miltonm@bga•com>
Cc: Nick Piggin <npiggin@kernel•dk>,
	Eric Dumazet <eric.dumazet@gmail•com>,
	Ingo Molnar <mingo@elte•hu>,
	linux-kernel@vger•kernel.org,
	Linus Torvalds <torvalds@linux-foundation•org>,
	Andi Kleen <andi@firstfloor•org>,
	Anton Blanchard <anton@samba•org>,
	Andrew Morton <akpm@linux-foundation•org>,
	linuxppc-dev@lists•ozlabs.org,
	Thomas Gleixner <tglx@linutronix•de>
Subject: Re: [PATCH] seqlock: don't smp_rmb in seqlock reader spin loop
Date: Thu, 12 May 2011 16:08:32 +0200	[thread overview]
Message-ID: <20110512140832.GK6008@one.firstfloor.org> (raw)
In-Reply-To: <seqlock-rmb@mdm.bga.com>

On Thu, May 12, 2011 at 04:13:54AM -0500, Milton Miller wrote:
> 
> Move the smp_rmb after cpu_relax loop in read_seqlock and add
> ACCESS_ONCE to make sure the test and return are consistent.
> 
> A multi-threaded core in the lab didn't like the update

Which core was that?

-Andi

      parent reply	other threads:[~2011-05-12 14:34 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1304574244.32152.666.camel@edumazet-laptop>
     [not found] ` <1304576495.2943.40.camel@work-vm>
     [not found]   ` <1304604284.3032.78.camel@edumazet-laptop>
     [not found]     ` <alpine.LFD.2.02.1105051630390.3005@ionos>
     [not found]       ` <1304608095.3032.95.camel@edumazet-laptop>
     [not found]         ` <alpine.LFD.2.02.1105051750540.3005@ionos>
     [not found]           ` <20110505210118.GI2925@one.firstfloor.org>
     [not found]             ` <alpine.LFD.2.02.1105061117220.3005@ionos>
     [not found]               ` <20110506165913.GF11636@one.firstfloor.org>
     [not found]                 ` <1304703767.3066.211.camel@edumazet-laptop>
     [not found]                   ` <20110506175051.GL11636@one.firstfloor.org>
     [not found]                     ` <1304710003.2821.0.camel@edumazet-laptop>
     [not found]                       ` <1304712267.2821.29.camel@edumazet-laptop>
     [not found]                         ` <1304713443.20980.124.camel@work-vm>
     [not found]                           ` <1304721004.2821.148.camel@edumazet-laptop>
     [not found]                             ` <1304722000.20980.130.camel@work-vm>
     [not found]                               ` <1304722835.2821.192.camel@edumazet-laptop>
     [not found]                                 ` <1304724519.20980.139.camel@work-vm>
     [not found]                                   ` <alpine.LFD.2.02.1105091036000.2895@ionos>
2011-05-12  9:13                                     ` [PATCH] seqlock: don't smp_rmb in seqlock reader spin loop, [PATCH] seqlock: don't smp_rmb in seqlock reader spin loop Milton Miller
2011-05-12  9:35                                       ` Eric Dumazet
2011-05-12 14:08                                       ` Andi Kleen [this message]

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