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From: Tejun Heo <tj@kernel.org>
To: cl@linux-foundation.org
Cc: linux-kernel@vger.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Pekka Enberg <penberg@cs.helsinki.fi>, Mel Gorman <mel@csn.ul.ie>
Subject: Re: [this_cpu_xx V6 7/7] this_cpu: slub aggressive use of this_cpu operations in the hotpaths
Date: Mon, 12 Oct 2009 19:40:37 +0900	[thread overview]
Message-ID: <4AD307A5.105@kernel.org> (raw)
In-Reply-To: <20091007211053.378634196@gentwo.org>

cl@linux-foundation.org wrote:
> Use this_cpu_* operations in the hotpath to avoid calculations of
> kmem_cache_cpu pointer addresses.
> 
> On x86 there is a trade off: Multiple uses segment prefixes against an
> address calculation and more register pressure. Code size is reduced
> also therefore it is an advantage icache wise.
> 
> The use of prefixes is necessary if we want to use a scheme
> for fastpaths that do not require disabling interrupts.
> 
> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Cc: Pekka Enberg <penberg@cs.helsinki.fi>
> Signed-off-by: Christoph Lameter <cl@linux-foundation.org>

The rest of the patches look good to me but I'm no expert in this area
of code.  But you're the maintainer of the allocator and the changes
definitely are percpu related, so if you're comfortable with it, I can
happily carry the patches through percpu tree.

Thanks.

-- 
tejun

  reply	other threads:[~2009-10-12 10:42 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-07 21:10 [this_cpu_xx V6 0/7] Introduce per cpu atomic operations and avoid per cpu address arithmetic cl
2009-10-07 21:10 ` [this_cpu_xx V6 1/7] this_cpu_ops: page allocator conversion cl
2009-10-08 10:38   ` Tejun Heo
2009-10-08 10:40     ` Tejun Heo
2009-10-08 16:15     ` Christoph Lameter
2009-10-08 10:53   ` Mel Gorman
2009-10-07 21:10 ` [this_cpu_xx V6 2/7] this_cpu ops: Remove pageset_notifier cl
2009-10-07 21:10 ` [this_cpu_xx V6 3/7] Use this_cpu operations in slub cl
2009-10-12 10:19   ` Tejun Heo
2009-10-12 10:21     ` Tejun Heo
2009-10-12 14:54     ` Christoph Lameter
2009-10-13  2:13       ` Tejun Heo
2009-10-13 14:41         ` Christoph Lameter
2009-10-13 14:56           ` Tejun Heo
2009-10-13 15:20             ` Christoph Lameter
2009-10-14  1:57               ` Tejun Heo
2009-10-14 14:14                 ` Christoph Lameter
2009-10-15  7:47                   ` Tejun Heo
2009-10-16 16:44                     ` Christoph Lameter
2009-10-18  3:11                       ` Tejun Heo
2009-10-07 21:10 ` [this_cpu_xx V6 4/7] SLUB: Get rid of dynamic DMA kmalloc cache allocation cl
2009-10-13 18:48   ` [FIX] patch "SLUB: Get rid of dynamic DMA kmalloc cache allocation" Christoph Lameter
2009-10-07 21:10 ` [this_cpu_xx V6 5/7] this_cpu: Remove slub kmem_cache fields cl
2009-10-07 23:10   ` Christoph Lameter
2009-10-07 21:10 ` [this_cpu_xx V6 6/7] Make slub statistics use this_cpu_inc cl
2009-10-07 21:10 ` [this_cpu_xx V6 7/7] this_cpu: slub aggressive use of this_cpu operations in the hotpaths cl
2009-10-12 10:40   ` Tejun Heo [this message]
2009-10-12 13:14     ` Pekka Enberg
2009-10-12 14:55       ` Christoph Lameter
2009-10-13  9:45       ` David Rientjes
2009-10-13 14:43         ` Christoph Lameter
2009-10-13 19:14           ` Christoph Lameter
2009-10-13 19:44             ` Pekka Enberg
2009-10-13 19:48               ` Christoph Lameter
2009-10-13 20:15                 ` David Rientjes
2009-10-13 20:28                   ` Christoph Lameter
2009-10-13 22:53                     ` David Rientjes
2009-10-14 13:34                       ` Mel Gorman
2009-10-14 14:08                         ` Christoph Lameter
2009-10-14 15:49                           ` Mel Gorman
2009-10-14 15:53                             ` Pekka Enberg
2009-10-14 15:56                               ` Christoph Lameter
2009-10-14 16:14                                 ` Pekka Enberg
2009-10-14 18:19                                   ` Christoph Lameter
2009-10-16 10:50                                 ` Mel Gorman
2009-10-16 18:40                                   ` David Rientjes
2009-10-15  9:03                         ` David Rientjes
2009-10-16 16:45                           ` Christoph Lameter
2009-10-16 18:43                             ` David Rientjes
2009-10-16 18:50                               ` Christoph Lameter
2009-10-13 20:25               ` Christoph Lameter
2009-10-14  1:33           ` David Rientjes
2009-10-13 15:40 ` [this_cpu_xx V6 0/7] Introduce per cpu atomic operations and avoid per cpu address arithmetic Mel Gorman
2009-10-13 15:45   ` Christoph Lameter
2009-10-13 16:09     ` Mel Gorman
2009-10-13 17:17       ` Christoph Lameter

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