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SubjectRe: [PATCH 11/25] Calculate the cold parameter for allocation only once
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On Mon, 2009-04-20 at 23:19 +0100, Mel Gorman wrote:
> GFP mask is checked for __GFP_COLD has been specified when deciding which
> end of the PCP lists to use. However, it is happening multiple times per
> allocation, at least once per zone traversed. Calculate it once.
>
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> ---
> mm/page_alloc.c | 35 ++++++++++++++++++-----------------
> 1 files changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 1506cd5..51e1ded 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1066,11 +1066,10 @@ void split_page(struct page *page, unsigned int order)
> */
> static struct page *buffered_rmqueue(struct zone *preferred_zone,
> struct zone *zone, int order, gfp_t gfp_flags,
> - int migratetype)
> + int migratetype, int cold)
> {
> unsigned long flags;
> struct page *page;
> - int cold = !!(gfp_flags & __GFP_COLD);
> int cpu;
>
> again:

Is this a measurable win? And does gcc inline all this nicely or does
this change actually increase kernel text size?



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