Re: [stable] [PATCH] mm: compaction: Abort compaction if too manypages are isolated and caller is asynchronous

From: Greg KH
Date: Mon May 30 2011 - 10:51:08 EST


On Mon, May 30, 2011 at 02:13:00PM +0100, Mel Gorman wrote:
> Asynchronous compaction is used when promoting to huge pages. This is
> all very nice but if there are a number of processes in compacting
> memory, a large number of pages can be isolated. An "asynchronous"
> process can stall for long periods of time as a result with a user
> reporting that firefox can stall for 10s of seconds. This patch aborts
> asynchronous compaction if too many pages are isolated as it's better to
> fail a hugepage promotion than stall a process.
>
> If accepted, this should also be considered for 2.6.39-stable. It should
> also be considered for 2.6.38-stable but ideally [11bc82d6: mm:
> compaction: Use async migration for __GFP_NO_KSWAPD and enforce no
> writeback] would be applied to 2.6.38 before consideration.
>
> Reported-and-Tested-by: Ury Stankevich <urykhy@xxxxxxxxx>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
> ---
> mm/compaction.c | 32 ++++++++++++++++++++++++++------
> 1 files changed, 26 insertions(+), 6 deletions(-)


<formletter>

This is not the correct way to submit patches for inclusion in the
stable kernel tree. Please read Documentation/stable_kernel_rules.txt
for how to do this properly.

</formletter>
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