On Mon, 26 Feb 2018, Aaron Lu wrote:
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 3154859cccd6..35576da0a6c9 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -1116,13 +1116,11 @@ static void free_pcppages_bulk(struct zone *zone, int
> count,
> int migratetype = 0;
> int batch_free = 0;
> bool isolated_pageblocks;
> + struct page *page, *tmp;
> + LIST_HEAD(head);
>
> pcp->count -= count;
> - spin_lock(&zone->lock);
> - isolated_pageblocks = has_isolate_pageblock(zone);
> -
> while (count) {
> - struct page *page;
> struct list_head *list;
>
> /*
> @@ -1144,26 +1142,31 @@ static void free_pcppages_bulk(struct zone *zone, int
> count,
> batch_free = count;
>
> do {
> - int mt; /* migratetype of the to-be-freed page */
> -
> page = list_last_entry(list, struct page, lru);
> /* must delete as __free_one_page list manipulates */
Looks good in general, but I'm not sure how I reconcile this comment with
the new implementation that later links page->lru again.
> list_del(&page->lru);
>
> - mt = get_pcppage_migratetype(page);
> - /* MIGRATE_ISOLATE page should not go to pcplists */
> - VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
> - /* Pageblock could have been isolated meanwhile */
> - if (unlikely(isolated_pageblocks))
> - mt = get_pageblock_migratetype(page);
> -
> if (bulkfree_pcp_prepare(page))
> continue;
>
> - __free_one_page(page, page_to_pfn(page), zone, 0, mt);
> - trace_mm_page_pcpu_drain(page, 0, mt);
> + list_add_tail(&page->lru, &head);
> } while (--count && --batch_free && !list_empty(list));
> }
> +
> + spin_lock(&zone->lock);
> + isolated_pageblocks = has_isolate_pageblock(zone);
> +
> + list_for_each_entry_safe(page, tmp, &head, lru) {
> + int mt = get_pcppage_migratetype(page);
> + /* MIGRATE_ISOLATE page should not go to pcplists */
> + VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
> + /* Pageblock could have been isolated meanwhile */
> + if (unlikely(isolated_pageblocks))
> + mt = get_pageblock_migratetype(page);
> +
> + __free_one_page(page, page_to_pfn(page), zone, 0, mt);
> + trace_mm_page_pcpu_drain(page, 0, mt);
> + }
> spin_unlock(&zone->lock);
> }
>
