Re: [PATCH 3/4] vmscan: zone_reclaim use may_swap

[Johannes Weiner]

On Wed, May 13, 2009 at 12:07:30PM +0900, KOSAKI Motohiro wrote:
> Subject: [PATCH] vmscan: zone_reclaim use may_swap
> 
> Documentation/sysctl/vm.txt says
> 
> 	zone_reclaim_mode:
> 
> 	Zone_reclaim_mode allows someone to set more or less aggressive approaches to
> 	reclaim memory when a zone runs out of memory. If it is set to zero then no
> 	zone reclaim occurs. Allocations will be satisfied from other zones / nodes
> 	in the system.
> 
> 	This is value ORed together of
> 
> 	1	= Zone reclaim on
> 	2	= Zone reclaim writes dirty pages out
> 	4	= Zone reclaim swaps pages
> 
> 
> So, "(zone_reclaim_mode & RECLAIM_SWAP) == 0" mean we don't want to reclaim
> swap-backed pages. not mapped file.
> 
> Thus, may_swap is better than may_unmap.
> 
> 
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxx>

Reviewed-by: Johannes Weiner <hannes@xxxxxxxxxxx>
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