On Mon 27-02-17 18:02:36, Minchan Kim wrote:
[...]
> >From 9779a1c5d32e2edb64da5cdfcd6f9737b94a247a Mon Sep 17 00:00:00 2001
> From: Minchan Kim <minc...@kernel.org>
> Date: Mon, 27 Feb 2017 17:39:06 +0900
> Subject: [PATCH] mm: use up highatomic before OOM kill
>
> Not-Yet-Signed-off-by: Minchan Kim <minc...@kernel.org>
> ---
> mm/page_alloc.c | 14 ++++----------
> 1 file changed, 4 insertions(+), 10 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 614cd0397ce3..e073cca4969e 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3549,16 +3549,6 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
> *no_progress_loops = 0;
> else
> (*no_progress_loops)++;
> -
> - /*
> - * Make sure we converge to OOM if we cannot make any progress
> - * several times in the row.
> - */
> - if (*no_progress_loops > MAX_RECLAIM_RETRIES) {
> - /* Before OOM, exhaust highatomic_reserve */
> - return unreserve_highatomic_pageblock(ac, true);
> - }
> -
> /*
> * Keep reclaiming pages while there is a chance this will lead
> * somewhere. If none of the target zones can satisfy our allocation
> @@ -3821,6 +3811,10 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int
> order,
> if (read_mems_allowed_retry(cpuset_mems_cookie))
> goto retry_cpuset;
>
> + /* Before OOM, exhaust highatomic_reserve */
> + if (unreserve_highatomic_pageblock(ac, true))
> + goto retry;
> +
OK, this can help for higher order requests when we do not exhaust all
the retries and fail on compaction but I fail to see how can this help
for order-0 requets which was what happened in this case. I am not
saying this is wrong, though.
> /* Reclaim has failed us, start killing things */
> page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress);
> if (page)
> --
> 2.7.4
--
Michal Hocko
SUSE Labs
