Re: [PATCH] mm: skip the page buddy block instead of one page

[Xishi Qiu]

On 2013/8/14 16:57, Mel Gorman wrote:

> On Wed, Aug 14, 2013 at 12:45:41PM +0800, Xishi Qiu wrote:
>> A large free page buddy block will continue many times, so if the page 
>> is free, skip the whole page buddy block instead of one page.
>>
>> Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
> 
> page_order cannot be used unless zone->lock is held which is not held in
> this path. Acquiring the lock would prevent parallel allocations from the
> buddy allocator (per-cpu allocator would be ok except for refills).  I expect
> it would not be a good tradeoff to acquire the lock just to use page_order.
> 
> Nak.
> 

Oh, you are right, we must hold zone->lock first.

Thanks,
Xishi Qiu
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