From 6de2b1aab94355482bd2accdc115666509667458 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Wed, 8 Sep 2010 10:19:36 +0900 Subject: HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page() This check is necessary to avoid race between dequeue and allocation, which can cause a free hugepage to be dequeued twice and get kernel unstable. Signed-off-by: Naoya Horiguchi Signed-off-by: Wu Fengguang Acked-by: Mel Gorman Reviewed-by: Christoph Lameter Signed-off-by: Andi Kleen --- mm/hugetlb.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) (limited to 'mm/hugetlb.c') diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 0fa9de8..deb7beb 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2955,18 +2955,39 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) hugetlb_acct_memory(h, -(chg - freed)); } +/* Should be called in hugetlb_lock */ +static int is_hugepage_on_freelist(struct page *hpage) +{ + struct page *page; + struct page *tmp; + struct hstate *h = page_hstate(hpage); + int nid = page_to_nid(hpage); + + list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru) + if (page == hpage) + return 1; + return 0; +} + +#ifdef CONFIG_MEMORY_FAILURE /* * This function is called from memory failure code. * Assume the caller holds page lock of the head page. */ -void __isolate_hwpoisoned_huge_page(struct page *hpage) +int dequeue_hwpoisoned_huge_page(struct page *hpage) { struct hstate *h = page_hstate(hpage); int nid = page_to_nid(hpage); + int ret = -EBUSY; spin_lock(&hugetlb_lock); - list_del(&hpage->lru); - h->free_huge_pages--; - h->free_huge_pages_node[nid]--; + if (is_hugepage_on_freelist(hpage)) { + list_del(&hpage->lru); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + ret = 0; + } spin_unlock(&hugetlb_lock); + return ret; } +#endif -- cgit v1.1