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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 <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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4
include/linux/hugetlb.h
View File

@ -43,7 +43,7 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to,
struct vm_area_struct *vma,
int acctflags);
void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed);
void __isolate_hwpoisoned_huge_page(struct page *page);
int dequeue_hwpoisoned_huge_page(struct page *page);
void copy_huge_page(struct page *dst, struct page *src);
extern unsigned long hugepages_treat_as_movable;
@ -102,7 +102,7 @@ static inline void hugetlb_report_meminfo(struct seq_file *m)
#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
#define hugetlb_fault(mm, vma, addr, flags) ({ BUG(); 0; })
#define huge_pte_offset(mm, address) 0
#define __isolate_hwpoisoned_huge_page(page) 0
#define dequeue_hwpoisoned_huge_page(page) 0
static inline void copy_huge_page(struct page *dst, struct page *src)
{
}

29
mm/hugetlb.c
View File

@ -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

6
mm/memory-failure.c
View File

@ -698,6 +698,7 @@ static int me_swapcache_clean(struct page *p, unsigned long pfn)
*/
static int me_huge_page(struct page *p, unsigned long pfn)
{
int res = 0;
struct page *hpage = compound_head(p);
/*
* We can safely recover from error on free or reserved (i.e.
@ -710,8 +711,9 @@ static int me_huge_page(struct page *p, unsigned long pfn)
* so there is no race between isolation and mapping/unmapping.
*/
if (!(page_mapping(hpage) || PageAnon(hpage))) {
__isolate_hwpoisoned_huge_page(hpage);
return RECOVERED;
res = dequeue_hwpoisoned_huge_page(hpage);
if (!res)
return RECOVERED;
}
return DELAYED;
}