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From: eric.dumazet@gmail.com (Eric Dumazet)
To: linux-arm-kernel@lists.infradead.org
Subject: [BUG] 2.6.37-rc3 massive interactivity regression on ARM
Date: Fri, 10 Dec 2010 21:49:25 +0100	[thread overview]
Message-ID: <1292014165.2746.9.camel@edumazet-laptop> (raw)
In-Reply-To: <1292013590.2746.2.camel@edumazet-laptop>

Le vendredi 10 d?cembre 2010 ? 21:39 +0100, Eric Dumazet a ?crit :

> This was exactly my suggestion Christoph.
> 
> I am glad you understand it now.
> 
> 

By the way, we need smp_wmb(), not barrier(), even only the "owner cpu"
can write into its 'percpu' seqcount.

There is nothing special about a seqcount being percpu or a 'global'
one. We must have same memory barrier semantics.

	this_cpu_write_seqcount_begin(&myseqcount);
	this_cpu_add(mydata1, add1);
	this_cpu_add(mydata2, add2);
	this_cpu_inc(mydata3);
	this_cpu_write_seqcount_end(&myseqcount);

We protect the data[1,2,3] set with a seqcount, so need smp_wmb() in
both _begin() and _end()

  reply	other threads:[~2010-12-10 20:49 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-27 15:16 [BUG] 2.6.37-rc3 massive interactivity regression on ARM Mikael Pettersson
2010-12-05 12:32 ` Mikael Pettersson
2010-12-05 13:17   ` Russell King - ARM Linux
2010-12-05 14:19     ` Russell King - ARM Linux
2010-12-05 16:07       ` Mikael Pettersson
2010-12-05 16:21         ` Russell King - ARM Linux
2010-12-08 12:40           ` Peter Zijlstra
2010-12-08 12:55             ` Russell King - ARM Linux
2010-12-08 14:04               ` Peter Zijlstra
2010-12-08 14:28                 ` Russell King - ARM Linux
2010-12-08 14:44                   ` Peter Zijlstra
2010-12-08 15:05                     ` Russell King - ARM Linux
2010-12-08 15:43                     ` Linus Walleij
2010-12-08 20:42                     ` john stultz
2010-12-08 23:31                   ` Venkatesh Pallipadi
2010-12-09 12:52                     ` Peter Zijlstra
2010-12-09 17:43                       ` Venkatesh Pallipadi
2010-12-09 17:55                         ` Peter Zijlstra
2010-12-09 18:11                           ` Venkatesh Pallipadi
2010-12-09 18:55                             ` Peter Zijlstra
2010-12-09 22:21                               ` Venkatesh Pallipadi
2010-12-09 23:16                                 ` Peter Zijlstra
2010-12-09 23:35                                   ` Venkatesh Pallipadi
2010-12-10 10:08                                     ` Peter Zijlstra
2010-12-10 13:17                                       ` Peter Zijlstra
2010-12-10 13:27                                         ` Peter Zijlstra
2010-12-10 13:47                                           ` Peter Zijlstra
2010-12-10 16:50                                             ` Russell King - ARM Linux
2010-12-10 16:54                                               ` Peter Zijlstra
2010-12-10 17:18                                             ` Eric Dumazet
2010-12-10 17:49                                               ` Peter Zijlstra
2010-12-10 18:14                                                 ` Eric Dumazet
2010-12-10 18:39                                                   ` Christoph Lameter
2010-12-10 18:46                                                     ` Peter Zijlstra
2010-12-10 19:51                                                       ` Christoph Lameter
2010-12-10 20:07                                                         ` Peter Zijlstra
2010-12-10 20:23                                                           ` Christoph Lameter
2010-12-10 20:32                                                             ` Peter Zijlstra
2010-12-10 20:39                                                             ` Eric Dumazet
2010-12-10 20:49                                                               ` Eric Dumazet [this message]
2010-12-10 21:09                                                                 ` Christoph Lameter
2010-12-10 21:22                                                                   ` Eric Dumazet
2010-12-10 21:45                                                                     ` Christoph Lameter
2010-12-10 17:56                                             ` Russell King - ARM Linux
2010-12-10 18:10                                               ` Peter Zijlstra
2010-12-10 18:43                                                 ` Peter Zijlstra
2010-12-10 19:17                                                 ` Russell King - ARM Linux
2010-12-10 19:37                                                   ` Peter Zijlstra
2010-12-10 19:25                                                 ` Peter Zijlstra
2010-12-13 14:33                             ` Jack Daniel
2010-12-06 21:29       ` Venkatesh Pallipadi

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