Re: [PATCH v2 4/6] mm: Only IPI CPUs to drain local pages if they exist

From: Gilad Ben-Yossef
Date: Sat Oct 29 2011 - 11:34:49 EST


On Fri, Oct 28, 2011 at 6:07 PM, Rik van Riel <riel@xxxxxxxxxx> wrote:
> On 10/23/2011 11:56 AM, Gilad Ben-Yossef wrote:
>>
>> Use a cpumask to track CPUs with per-cpu pages in any zone
>> and only send an IPI requesting CPUs to drain these pages
>> to the buddy allocator if they actually have pages.
>
>> +/* Which CPUs have per cpu pages  */
>> +cpumask_var_t cpus_with_pcp;
>> +static DEFINE_PER_CPU(unsigned long, total_cpu_pcp_count);
>
> Does the flushing happen so frequently that it is worth keeping this
> state on a per-cpu basis, or would it be better to check each CPU's
> pcp info and assemble a cpumask at flush time like done in patch 5?
>

No, I don't believe it is frequent at all. I will try to re-work the
patch as suggested.

Thanks,
Gilad

>

>
> --
> All rights reversed
>



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Gilad Ben-Yossef
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