Re: [PATCH 7/9] try harder on large allocations

[Coywolf Qi Hunt <coywolf@gmail.com>]

On 9/27/05, Joel Schopp <jschopp@austin.ibm.com> wrote:
> Fragmentation avoidance patches increase our chances of satisfying high order
> allocations.  So this patch takes more than one iteration at trying to fulfill
> those allocations because unlike before the extra iterations are often useful.
>
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com>
>
>
> Index: 2.6.13-joel2/mm/page_alloc.c
> ===================================================================
> --- 2.6.13-joel2.orig/mm/page_alloc.c   2005-09-21 11:13:14.%N -0500
> +++ 2.6.13-joel2/mm/page_alloc.c        2005-09-21 11:14:49.%N -0500
> @@ -944,7 +944,8 @@ __alloc_pages(unsigned int __nocast gfp_
>         int can_try_harder;
>         int did_some_progress;
>         int alloctype;
> -
> +       int highorder_retry = 3;
> +
>         alloctype = (gfp_mask & __GFP_RCLM_BITS);
>         might_sleep_if(wait);
>
> @@ -1090,7 +1091,14 @@ rebalance:
>                                 goto got_pg;
>                 }
>
> -               out_of_memory(gfp_mask, order);
> +               if (order < MAX_ORDER/2) out_of_memory(gfp_mask, order);

Shouldn't that be written in two lines?

> +               /*
> +                * Due to low fragmentation efforts, we should try a little
> +                * harder to satisfy high order allocations
> +                */
> +               if (order >= MAX_ORDER/2 && --highorder_retry > 0)
> +                       goto rebalance;
> +
>                 goto restart;
>         }

--
Coywolf Qi Hunt
http://sosdg.org/~coywolf/