Re: [RFC PATCH 2/3] mm, page_alloc: get page

[Wenwei Tao]

Hi
Something is wrong with my email, I cannot send the patch out, and
this patch commit title is not complete.
Apologize for the noise.

2016-06-18 19:45 GMT+08:00 Wenwei Tao <linuxtao_hit@xxxxxxx>:
> From: Wenwei Tao <ww.tao0320@xxxxxxxxx>
>
> The migratetype might get staled, pages might have become highatomic when
> we try to free them to the allocator, we might not want to put highatomic
> pages into other buddy lists, since they are reserved only for atomic high
> order use. And also highatomic pages could have been unreserved,
> put them into the hightatomic buddy list might exceed the limit of
> highatomic pages. So get the pages migreate type again to put them into
> the right lists.
>
> Signed-off-by: Wenwei Tao <ww.tao0320@xxxxxxxxx>
> ---
>  mm/page_alloc.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 19f9e76..b72b771 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1079,9 +1079,11 @@ static void free_pcppages_bulk(struct zone *zone, int count,
>         int batch_free = 0;
>         unsigned long nr_scanned;
>         bool isolated_pageblocks;
> +       bool reserved_highatomic;
>
>         spin_lock(&zone->lock);
>         isolated_pageblocks = has_isolate_pageblock(zone);
> +       reserved_highatomic = !!zone->nr_reserved_highatomic;
>         nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
>         if (nr_scanned)
>                 __mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
> @@ -1118,8 +1120,10 @@ static void free_pcppages_bulk(struct zone *zone, int count,
>                         mt = get_pcppage_migratetype(page);
>                         /* MIGRATE_ISOLATE page should not go to pcplists */
>                         VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
> +                       VM_BUG_ON_PAGE(mt == MIGRATE_HIGHATOMIC, page);
>                         /* Pageblock could have been isolated meanwhile */
> -                       if (unlikely(isolated_pageblocks))
> +                       if (unlikely(isolated_pageblocks ||
> +                                       reserved_highatomic))
>                                 mt = get_pageblock_migratetype(page);
>
>                         if (bulkfree_pcp_prepare(page))
> @@ -1144,7 +1148,9 @@ static void free_one_page(struct zone *zone,
>                 __mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
>
>         if (unlikely(has_isolate_pageblock(zone) ||
> -               is_migrate_isolate(migratetype))) {
> +               zone->nr_reserved_highatomic ||
> +               is_migrate_isolate(migratetype) ||
> +               migratetype == MIGRATE_HIGHATOMIC)) {
>                 migratetype = get_pfnblock_migratetype(page, pfn);
>         }
>         __free_one_page(page, pfn, zone, order, migratetype);
> --
> 1.8.3.1
>
>