Re: [patch 2/9] mempool gfp flag

Andrew Morton
2005-04-12T21:02:11Z

Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
> The first is that mempool_alloc can possibly get stuck in __alloc_pages
> when they should opt to fail, and take an element from their reserved pool.
>
> The second is that it will happily eat emergency PF_MEMALLOC reserves
> instead of going to their reserved pools.
>
> Fix the first by passing __GFP_NORETRY in the allocation calls in
> mempool_alloc. Fix the second by introducing a __GFP_MEMPOOL flag
> which directs the page allocator not to allocate from the reserve
> pool.
>
>
> Index: linux-2.6/include/linux/gfp.h
> ===================================================================
> --- linux-2.6.orig/include/linux/gfp.h 2005-04-12 22:26:10.000000000 +1000
> +++ linux-2.6/include/linux/gfp.h 2005-04-12 22:26:11.000000000 +1000
> @@ -38,14 +38,16 @@ struct vm_area_struct;
> #define __GFP_NO_GROW 0x2000u /* Slab internal usage */
> #define __GFP_COMP 0x4000u /* Add compound page metadata */
> #define __GFP_ZERO 0x8000u /* Return zeroed page on success */
> +#define __GFP_MEMPOOL 0x10000u/* Mempool allocation */

I think I'll rename this to "__GFP_NOMEMALLOC". Things other then mempool
might want to use this.