From: Tejun Heo <tj@kernel.org>
To: Christoph Lameter <cl@linux-foundation.org>
Cc: 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 V6 3/7] Use this_cpu operations in slub
Date: Tue, 13 Oct 2009 11:13:15 +0900 [thread overview]
Message-ID: <4AD3E23B.8020103@kernel.org> (raw)
In-Reply-To: <alpine.DEB.1.10.0910121053240.7932@gentwo.org>
Christoph Lameter wrote:
> On Mon, 12 Oct 2009, Tejun Heo wrote:
>
>>> - c = get_cpu_slab(s, smp_processor_id());
>>> + c = __this_cpu_ptr(s->cpu_slab);
>> Shouldn't this be this_cpu_ptr() without the double underscore?
>
> Interrupts are disabled so no concurrent fast path can occur.
>
The only difference between this_cpu_ptr() and __this_cpu_ptr() is the
usage of my_cpu_offset and __my_cpu_offset which in turn are only
different in whether they check preemption status to make sure the cpu
is pinned down when called.
The only places where the underbar prefixed versions should be used
are places where cpu locality is nice but not critical and preemption
debug check wouldn't work properly for whatever reason. The above is
none of the two and the conversion is buried in a patch which is
supposed to do something else. Am I missing something?
--
tejun
next prev parent reply other threads:[~2009-10-13 2:14 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 [this message]
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
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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