From 4ef91848043679b272a1a5b8e2879acf696ba9e2 Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Date: Wed, 11 Sep 2013 14:21:51 -0700
Subject: [PATCH] mm, hugetlb: protect reserved pages when soft offlining a
hugepage
Don't use the reserve pool when soft offlining a hugepage. Check we have
free pages outside the reserve pool before we dequeue the huge page.
Otherwise, we can steal other's reserve page.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/hugetlb.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5b084c7b34c6..583db1948145 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -955,10 +955,11 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
*/
struct page *alloc_huge_page_node(struct hstate *h, int nid)
{
- struct page *page;
+ struct page *page = NULL;
spin_lock(&hugetlb_lock);
- page = dequeue_huge_page_node(h, nid);
+ if (h->free_huge_pages - h->resv_huge_pages > 0)
+ page = dequeue_huge_page_node(h, nid);
spin_unlock(&hugetlb_lock);
if (!page)
--
2.34.1