From 685f345708096ed21078aa44a6f4a6e6d1d1b580 Mon Sep 17 00:00:00 2001 From: Lee Schermerhorn Date: Mon, 21 Sep 2009 17:01:23 -0700 Subject: [PATCH] hugetlb: use free_pool_huge_page() to return unused surplus pages Use the [modified] free_pool_huge_page() function to return unused surplus pages. This will help keep huge pages balanced across nodes between freeing of unused surplus pages and freeing of persistent huge pages [from set_max_huge_pages] by using the same node id "cursor". It also eliminates some code duplication. Signed-off-by: Lee Schermerhorn Cc: Mel Gorman Cc: Nishanth Aravamudan Acked-by: David Rientjes Cc: Adam Litke Cc: Andy Whitcroft Cc: Eric Whitney Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 57 ++++++++++++++++++++++------------------------------ 1 file changed, 24 insertions(+), 33 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 38dab5586827..f10cc274a7d9 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -687,7 +687,7 @@ static int hstate_next_node_to_free(struct hstate *h) * balanced over allowed nodes. * Called with hugetlb_lock locked. */ -static int free_pool_huge_page(struct hstate *h) +static int free_pool_huge_page(struct hstate *h, bool acct_surplus) { int start_nid; int next_nid; @@ -697,13 +697,22 @@ static int free_pool_huge_page(struct hstate *h) next_nid = start_nid; do { - if (!list_empty(&h->hugepage_freelists[next_nid])) { + /* + * If we're returning unused surplus pages, only examine + * nodes with surplus pages. + */ + if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && + !list_empty(&h->hugepage_freelists[next_nid])) { struct page *page = list_entry(h->hugepage_freelists[next_nid].next, struct page, lru); list_del(&page->lru); h->free_huge_pages--; h->free_huge_pages_node[next_nid]--; + if (acct_surplus) { + h->surplus_huge_pages--; + h->surplus_huge_pages_node[next_nid]--; + } update_and_free_page(h, page); ret = 1; } @@ -884,22 +893,13 @@ free: * When releasing a hugetlb pool reservation, any surplus pages that were * allocated to satisfy the reservation must be explicitly freed if they were * never used. + * Called with hugetlb_lock held. */ static void return_unused_surplus_pages(struct hstate *h, unsigned long unused_resv_pages) { - static int nid = -1; - struct page *page; unsigned long nr_pages; - /* - * We want to release as many surplus pages as possible, spread - * evenly across all nodes. Iterate across all nodes until we - * can no longer free unreserved surplus pages. This occurs when - * the nodes with surplus pages have no free pages. - */ - unsigned long remaining_iterations = nr_online_nodes; - /* Uncommit the reservation */ h->resv_huge_pages -= unused_resv_pages; @@ -909,26 +909,17 @@ static void return_unused_surplus_pages(struct hstate *h, nr_pages = min(unused_resv_pages, h->surplus_huge_pages); - while (remaining_iterations-- && nr_pages) { - nid = next_node(nid, node_online_map); - if (nid == MAX_NUMNODES) - nid = first_node(node_online_map); - - if (!h->surplus_huge_pages_node[nid]) - continue; - - if (!list_empty(&h->hugepage_freelists[nid])) { - page = list_entry(h->hugepage_freelists[nid].next, - struct page, lru); - list_del(&page->lru); - update_and_free_page(h, page); - h->free_huge_pages--; - h->free_huge_pages_node[nid]--; - h->surplus_huge_pages--; - h->surplus_huge_pages_node[nid]--; - nr_pages--; - remaining_iterations = nr_online_nodes; - } + /* + * We want to release as many surplus pages as possible, spread + * evenly across all nodes. Iterate across all nodes until we + * can no longer free unreserved surplus pages. This occurs when + * the nodes with surplus pages have no free pages. + * free_pool_huge_page() will balance the the frees across the + * on-line nodes for us and will handle the hstate accounting. + */ + while (nr_pages--) { + if (!free_pool_huge_page(h, 1)) + break; } } @@ -1268,7 +1259,7 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count) min_count = max(count, min_count); try_to_free_low(h, min_count); while (min_count < persistent_huge_pages(h)) { - if (!free_pool_huge_page(h)) + if (!free_pool_huge_page(h, 0)) break; } while (count < persistent_huge_pages(h)) { -- 2.30.2