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

From: Mel Gorman
Date: Wed Aug 14 2013 - 04:57:23 EST


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.

--
Mel Gorman
SUSE Labs
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