Re: [PATCH 11/25] Calculate the cold parameter for allocation only once

KOSAKI Motohiro
2009-04-21T09:07:22Z

> 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;

Honestly, I don't like this ;-)

It seems benefit is too small. It don't win against code ugliness, I think.