From: Eric Dumazet <eric.dumazet@gmail.com>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org,
Pekka Enberg <penberg@cs.helsinki.fi>, Mel Gorman <mel@csn.ul.ie>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: Re: [this_cpu_xx V7 6/8] Make slub statistics use this_cpu_inc
Date: Tue, 15 Dec 2009 15:59:36 +0100 [thread overview]
Message-ID: <4B27A458.4090005@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.0912150836190.16754@router.home>
Le 15/12/2009 15:46, Christoph Lameter a écrit :
> On Tue, 15 Dec 2009, Eric Dumazet wrote:
>
>> Le 14/12/2009 23:03, Christoph Lameter a écrit :
>>> this_cpu_inc() translates into a single instruction on x86 and does not
>>> need any register. So use it in stat(). We also want to avoid the
>>> calculation of the per cpu kmem_cache_cpu structure pointer. So pass
>>> a kmem_cache pointer instead of a kmem_cache_cpu pointer.
>>>
>>
>> Hmm, last time I checked, [__]this_cpu_inc were not using "inc" on x86,
>> but the default [__]this_cpu_add((pcp), 1)
>
> Well the add 1 is still a single instruction so its okay. We can easily
> add support for inc on x86 if makes a difference?
>
Probably not, only one byte of text per use can be saved.
Sorry, rereading your changelog I dont know why I thought about "inc" instruction.
next prev parent reply other threads:[~2009-12-15 15:00 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-14 22:03 [this_cpu_xx V7 0/8] Per cpu atomics in core allocators and cleanup Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 1/8] this_cpu_ops: page allocator conversion Christoph Lameter
2009-12-15 3:53 ` Tejun Heo
2009-12-15 15:04 ` Christoph Lameter
2009-12-16 0:53 ` Tejun Heo
2009-12-16 14:55 ` Christoph Lameter
2009-12-17 0:23 ` Tejun Heo
2009-12-14 22:03 ` [this_cpu_xx V7 2/8] this_cpu ops: Remove pageset_notifier Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 3/8] Use this_cpu operations in slub Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 4/8] SLUB: Get rid of dynamic DMA kmalloc cache allocation Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 5/8] this_cpu: Remove slub kmem_cache fields Christoph Lameter
2009-12-14 22:03 ` [this_cpu_xx V7 6/8] Make slub statistics use this_cpu_inc Christoph Lameter
2009-12-15 6:24 ` Eric Dumazet
2009-12-15 14:46 ` Christoph Lameter
2009-12-15 14:59 ` Eric Dumazet [this message]
2009-12-14 22:03 ` [this_cpu_xx V7 7/8] Module handling: Use this_cpu_xx to dynamically allocate counters Christoph Lameter
2009-12-15 4:03 ` Tejun Heo
2009-12-15 22:41 ` Rusty Russell
2009-12-16 16:10 ` Christoph Lameter
2009-12-17 0:25 ` Tejun Heo
2009-12-17 5:42 ` Rusty Russell
2009-12-14 22:03 ` [this_cpu_xx V7 8/8] Remove cpu_local_xx macros Christoph Lameter
2009-12-15 4:04 ` Tejun Heo
2009-12-15 6:37 ` [this_cpu_xx V7 0/8] Per cpu atomics in core allocators and cleanup Pekka Enberg
2009-12-15 6:47 ` Tejun Heo
2009-12-15 14:50 ` Christoph Lameter
2009-12-15 17:06 ` Mel Gorman
2009-12-16 14:44 ` Christoph Lameter
2009-12-16 21:36 ` Christoph Lameter
2009-12-15 17:43 ` Mathieu Desnoyers
2009-12-16 0:58 ` Tejun Heo
2009-12-16 1:40 ` Mathieu Desnoyers
2009-12-16 1:46 ` Tejun Heo
2009-12-17 13:39 ` Mathieu Desnoyers
2009-12-17 19:28 ` Christoph Lameter
2009-12-17 20:25 ` Mathieu Desnoyers
2009-12-17 20:43 ` Christoph Lameter
2009-12-18 0:13 ` Mathieu Desnoyers
2009-12-18 0:27 ` Christoph Lameter
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