Re: [PATCH] mm: batch-free pcp list if possible

[Johannes Weiner <hannes@cmpxchg.org>]

On Wed, Feb 09, 2011 at 10:21:17PM +0900, Namhyung Kim wrote:
> free_pcppages_bulk() frees pages from pcp lists in a round-robin
> fashion by keeping batch_free counter. But it doesn't need to spin
> if there is only one non-empty list. This can be checked by
> batch_free == MIGRATE_PCPTYPES.
> 
> Signed-off-by: Namhyung Kim <namhyung@gmail.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

> ---
>  mm/page_alloc.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index a873e61e312e..470fb42e303c 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -614,6 +614,10 @@ static void free_pcppages_bulk(struct zone *zone, int count,
>  			list = &pcp->lists[migratetype];
>  		} while (list_empty(list));
>  
> +		/* This is an only non-empty list. Free them all. */
> +		if (batch_free == MIGRATE_PCPTYPES)
> +			batch_free = to_free;
> +
>  		do {
>  			page = list_entry(list->prev, struct page, lru);
>  			/* must delete as __free_one_page list manipulates */
> -- 
> 1.7.3.4.600.g982838b0
> 
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