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From: Tejun Heo <tj@kernel.org>
To: cl@linux-foundation.org
Cc: akpm@linux-foundation.org, linux-mm@kvack.org,
	David Howells <dhowells@redhat.com>, Ingo Molnar <mingo@elte.hu>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Eric Dumazet <dada1@cosmosbay.com>,
	davem@davemloft.net
Subject: Re: [this_cpu_xx V2 02/19] Introduce this_cpu_ptr() and generic this_cpu_* operations
Date: Thu, 18 Jun 2009 11:29:20 +0900	[thread overview]
Message-ID: <4A39A680.5070405@kernel.org> (raw)
In-Reply-To: <4A399D52.9040801@kernel.org>

Tejun Heo wrote:
> cl@linux-foundation.org wrote:
>> this_cpu_ptr
>> ------------
>>
>> this_cpu_ptr(xx) = per_cpu_ptr(xx, smp_processor_id).
>>
>> The problem with per_cpu_ptr(x, smp_processor_id) is that it requires
>> an array lookup to find the offset for the cpu. Processors typically
>> have the offset for the current cpu area in some kind of (arch dependent)
>> efficiently accessible register or memory location.
> ...
>> cc: David Howells <dhowells@redhat.com>
>> cc: Tejun Heo <tj@kernel.org>
>> cc: Ingo Molnar <mingo@elte.hu>
>> cc: Rusty Russell <rusty@rustcorp.com.au>
>> cc: Eric Dumazet <dada1@cosmosbay.com>
>> Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
> 
> Acked-by: Tejun Heo <tj@kernel.org>
> 

Oops, one problem.  this_cpu_ptr() should evaluate to the same type
pointer as input but it currently evaulates to unsigned long.

Thanks.

-- 
tejun

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  reply	other threads:[~2009-06-18  2:28 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-17 20:33 [this_cpu_xx V2 00/19] Introduce this_cpu_xx operations cl
2009-06-17 20:33 ` [this_cpu_xx V2 01/19] Fix handling of pagesets for downed cpus cl
2009-06-17 20:33 ` [this_cpu_xx V2 02/19] Introduce this_cpu_ptr() and generic this_cpu_* operations cl
2009-06-18  1:50   ` Tejun Heo
2009-06-18  2:29     ` Tejun Heo [this message]
2009-06-18 13:54       ` Christoph Lameter
2009-06-18 14:49         ` Tejun Heo
2009-06-17 20:33 ` [this_cpu_xx V2 03/19] Use this_cpu operations for SNMP statistics cl
2009-06-18  1:55   ` Tejun Heo
2009-06-17 20:33 ` [this_cpu_xx V2 04/19] Use this_cpu operations for NFS statistics cl
2009-06-18  2:03   ` Tejun Heo
2009-06-17 20:33 ` [this_cpu_xx V2 05/19] use this_cpu ops for network statistics cl
2009-06-17 20:33 ` [this_cpu_xx V2 06/19] this_cpu_ptr: Straight transformations cl
2009-06-17 20:33 ` [this_cpu_xx V2 07/19] this_cpu_ptr: Elimninate get/put_cpu cl
2009-06-17 20:33 ` [this_cpu_xx V2 08/19] this_cpu_ptr: xfs_icsb_modify_counters does not need "cpu" variable cl
2009-06-17 20:33 ` [this_cpu_xx V2 09/19] Use this_cpu_ptr in crypto subsystem cl
2009-06-17 20:33 ` [this_cpu_xx V2 10/19] this_cpu: X86 optimized this_cpu operations cl
2009-06-18  3:00   ` Tejun Heo
2009-06-18 14:07     ` Christoph Lameter
2009-06-18 14:48       ` Tejun Heo
2009-06-18 15:39         ` Christoph Lameter
2009-06-18 16:06           ` Tejun Heo
2009-06-18 16:15             ` Tejun Heo
2009-06-18 17:05             ` Christoph Lameter
2009-06-19  5:41             ` Rusty Russell
2009-06-23 18:00               ` Christoph Lameter
2009-06-17 20:33 ` [this_cpu_xx V2 11/19] Use this_cpu ops for VM statistics cl
2009-06-18  3:05   ` Tejun Heo
2009-06-17 20:33 ` [this_cpu_xx V2 12/19] RCU: Use this_cpu operations cl
2009-06-17 20:33 ` [this_cpu_xx V2 13/19] Use this_cpu operations in slub cl
2009-06-18  6:20   ` Pekka Enberg
2009-06-18  6:25     ` Pekka Enberg
2009-06-18 13:59       ` Christoph Lameter
2009-06-25  7:12         ` Pekka Enberg
2009-06-18  6:49     ` Tejun Heo
2009-06-18  7:35       ` Pekka Enberg
2009-06-18 13:59     ` Christoph Lameter
2009-06-25  7:11       ` Pekka Enberg
2009-06-17 20:33 ` [this_cpu_xx V2 14/19] this_cpu: Remove slub kmem_cache fields cl
2009-06-17 20:33 ` [this_cpu_xx V2 15/19] Make slub statistics use this_cpu_inc cl
2009-06-17 20:33 ` [this_cpu_xx V2 16/19] this_cpu: slub aggressive use of this_cpu operations in the hotpaths cl
2009-06-18  6:33   ` Pekka Enberg
2009-06-18 11:59     ` Mathieu Desnoyers
2009-06-18 14:00     ` Christoph Lameter
2009-06-17 20:33 ` [this_cpu_xx V2 17/19] Move early initialization of pagesets out of zone_wait_table_init() cl
2009-06-18  3:13   ` Tejun Heo
2009-06-17 20:33 ` [this_cpu_xx V2 18/19] this_cpu_ops: page allocator conversion cl
2009-06-17 20:33 ` [this_cpu_xx V2 19/19] this_cpu ops: Remove pageset_notifier cl

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