From 5bc7b8aca942d03bf2716ddcfcb4e0b57e43a1b8 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 29 Apr 2013 15:08:36 -0700 Subject: mm: thp: add split tail pages to shrink page list in page reclaim In page reclaim, huge page is split. split_huge_page() adds tail pages to LRU list. Since we are reclaiming a huge page, it's better we reclaim all subpages of the huge page instead of just the head page. This patch adds split tail pages to shrink page list so the tail pages can be reclaimed soon. Before this patch, run a swap workload: thp_fault_alloc 3492 thp_fault_fallback 608 thp_collapse_alloc 6 thp_collapse_alloc_failed 0 thp_split 916 With this patch: thp_fault_alloc 4085 thp_fault_fallback 16 thp_collapse_alloc 90 thp_collapse_alloc_failed 0 thp_split 1272 fallback allocation is reduced a lot. [akpm@linux-foundation.org: fix CONFIG_SWAP=n build] Signed-off-by: Shaohua Li Acked-by: Rik van Riel Acked-by: Minchan Kim Acked-by: Johannes Weiner Reviewed-by: Wanpeng Li Cc: Andrea Arcangeli Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/swap.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'mm/swap.c') diff --git a/mm/swap.c b/mm/swap.c index 8a529a01e8fc..acd40bfffa82 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -737,7 +737,7 @@ EXPORT_SYMBOL(__pagevec_release); #ifdef CONFIG_TRANSPARENT_HUGEPAGE /* used by __split_huge_page_refcount() */ void lru_add_page_tail(struct page *page, struct page *page_tail, - struct lruvec *lruvec) + struct lruvec *lruvec, struct list_head *list) { int uninitialized_var(active); enum lru_list lru; @@ -749,7 +749,8 @@ void lru_add_page_tail(struct page *page, struct page *page_tail, VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&lruvec_zone(lruvec)->lru_lock)); - SetPageLRU(page_tail); + if (!list) + SetPageLRU(page_tail); if (page_evictable(page_tail)) { if (PageActive(page)) { @@ -767,7 +768,11 @@ void lru_add_page_tail(struct page *page, struct page *page_tail, if (likely(PageLRU(page))) list_add_tail(&page_tail->lru, &page->lru); - else { + else if (list) { + /* page reclaim is reclaiming a huge page */ + get_page(page_tail); + list_add_tail(&page_tail->lru, list); + } else { struct list_head *list_head; /* * Head page has not yet been counted, as an hpage, -- cgit v1.2.2