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Commit 685f3457 authored by Lee Schermerhorn's avatar Lee Schermerhorn Committed by Linus Torvalds
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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: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Nishanth Aravamudan <nacc@us.ibm.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e8c5c824

mm/hugetlb.c

+24 −33
Original line number Diff line number Diff line
@@ -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 @@ static int gather_surplus_pages(struct hstate *h, int delta) 
 * 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)) {