Re: [PATCH 52 of 66] enable direct defrag

Mel Gorman
2010-11-18T16:17:57Z

On Wed, Nov 03, 2010 at 04:28:27PM +0100, Andrea Arcangeli wrote:
> From: Andrea Arcangeli <aarcange@redhat.com>
>
> With memory compaction in, and lumpy-reclaim removed, it seems safe enough to
> defrag memory during the (synchronous) transparent hugepage page faults
> (TRANSPARENT_HUGEPAGE_DEFRAG_FLAG) and not only during khugepaged (async)
> hugepage allocations that was already enabled even before memory compaction was
> in (TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG).
>

While I'm hoping that my series on using compaction will be used instead
of outright deletion of lumpy reclaim, this patch would still make
sense.

Acked-by: Mel Gorman <mel@csn.ul.ie>

> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
> ---
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -28,6 +28,7 @@
> */
> unsigned long transparent_hugepage_flags __read_mostly =
> (1<<TRANSPARENT_HUGEPAGE_FLAG)|
> + (1<<TRANSPARENT_HUGEPAGE_DEFRAG_FLAG)|
> (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG);
>
> /* default scan 8*512 pte (or vmas) every 30 second */
>

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab