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HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page()

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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 <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
This commit is contained in:
Naoya Horiguchi
2010-09-08 10:19:36 +09:00
committed by Andi Kleen
parent 290408d4a2
commit 6de2b1aab9
3 changed files with 31 additions and 8 deletions
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29
mm/hugetlb.c
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@@ -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