Re: [PATCH 15/17] mm: Do not use unnecessary atomic operations when adding pages to the LRU

From: Johannes Weiner
Date: Thu May 01 2014 - 09:33:48 EST


On Thu, May 01, 2014 at 09:44:46AM +0100, Mel Gorman wrote:
> When adding pages to the LRU we clear the active bit unconditionally. As the
> page could be reachable from other paths we cannot use unlocked operations
> without risk of corruption such as a parallel mark_page_accessed. This
> patch test if is necessary to clear the atomic flag before using an atomic
> operation. In the unlikely even this races with mark_page_accesssed the

event

> consequences are simply that the page may be promoted to the active list
> that might have been left on the inactive list before the patch. This is
> a marginal consequence.
>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
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