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Date: Fri, 19 Sep 2008 07:59:22 -0500
From: Christoph Lameter <cl@linux-foundation.org>
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To: Eric Dumazet <dada1@cosmosbay.com>
CC: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
       Christoph Lameter <clameter@sgi.com>, linux-mm@vger.kernel.org,
       jeremy@goop.org, ebiederm@xmission.com, travis@sgi.com,
       herbert@gondor.apana.org.au, xemul@openvz.org
Subject: Re: [patch 4/4] cpu alloc: Use cpu allocator instead of the builtin
 modules per cpu allocator
References: <20080918233648.581696416@quilx.com> <20080918233701.832528677@quilx.com> <48D3574B.40209@cosmosbay.com>
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Eric Dumazet wrote:
> Christoph Lameter a écrit :
>> Remove the builtin per cpu allocator from modules.c and use cpu_alloc
>> instead.
>>
>> Signed-off-by: Christoph Lameter <clameter@sgi.com>
> 
>> +        percpu_size = sechdrs[pcpuindex].sh_size;
>> +
>> +        if (align > PAGE_SIZE) {
>> +            printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
>> +                      mod->name, align, PAGE_SIZE);
>> +            align = PAGE_SIZE;
>> +        }
> 
> Minor question : Wy do you have to keep this cap of alignment ?
> 
> I could not find such a limit in the allocator

The per cpu areas are allocated on page boundaries and there are multiple of
those per cpu areas all aligned to page boundary. The alignment can therefore
only make sense up to a page. Maybe I need to put that into the cpu allocator?