Re: mm: Do not iterate over NR_CPUS in __zone_pcp_update()

[Pekka Enberg]

On Mon, Mar 8, 2010 at 11:21 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> __zone_pcp_update() iterates over NR_CPUS instead of limiting the
> access to the possible cpus. This might result in access to
> uninitialized areas as the per cpu allocator only populates the per
> cpu memory for possible cpus.
>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Looks OK to me.

Acked-by: Pekka Enberg <penberg@xxxxxxxxxxxxxx>

> ---
>  mm/page_alloc.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Index: linux-2.6/mm/page_alloc.c
> ===================================================================
> --- linux-2.6.orig/mm/page_alloc.c
> +++ linux-2.6/mm/page_alloc.c
> @@ -3224,7 +3224,7 @@ static int __zone_pcp_update(void *data)
>        int cpu;
>        unsigned long batch = zone_batchsize(zone), flags;
>
> -       for (cpu = 0; cpu < NR_CPUS; cpu++) {
> +       for_each_possible_cpu(cpu) {
>                struct per_cpu_pageset *pset;
>                struct per_cpu_pages *pcp;
>
>
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