diff options
author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2010-09-08 10:19:37 +0900 |
---|---|---|
committer | Andi Kleen <ak@linux.intel.com> | 2010-10-08 09:32:45 +0200 |
commit | a9869b837c098732bad84939015c0eb391b23e41 (patch) | |
tree | 00ba63997470724e2704c9b7c995c91672b53c7b /mm/hugetlb.c | |
parent | 6de2b1aab94355482bd2accdc115666509667458 (diff) | |
download | linux-a9869b837c098732bad84939015c0eb391b23e41.tar.bz2 |
hugetlb: move refcounting in hugepage allocation inside hugetlb_lock
Currently alloc_huge_page() raises page refcount outside hugetlb_lock.
but it causes race when dequeue_hwpoison_huge_page() runs concurrently
with alloc_huge_page().
To avoid it, this patch moves set_page_refcounted() in hugetlb_lock.
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>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r-- | mm/hugetlb.c | 35 |
1 files changed, 13 insertions, 22 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index deb7bebefe68..636be5d6aadd 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -509,6 +509,7 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid) return NULL; page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); list_del(&page->lru); + set_page_refcounted(page); h->free_huge_pages--; h->free_huge_pages_node[nid]--; return page; @@ -868,12 +869,6 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) spin_lock(&hugetlb_lock); if (page) { - /* - * This page is now managed by the hugetlb allocator and has - * no users -- drop the buddy allocator's reference. - */ - put_page_testzero(page); - VM_BUG_ON(page_count(page)); r_nid = page_to_nid(page); set_compound_page_dtor(page, free_huge_page); /* @@ -936,16 +931,13 @@ retry: spin_unlock(&hugetlb_lock); for (i = 0; i < needed; i++) { page = alloc_buddy_huge_page(h, NUMA_NO_NODE); - if (!page) { + if (!page) /* * We were not able to allocate enough pages to * satisfy the entire reservation so we free what * we've allocated so far. */ - spin_lock(&hugetlb_lock); - needed = 0; goto free; - } list_add(&page->lru, &surplus_list); } @@ -972,31 +964,31 @@ retry: needed += allocated; h->resv_huge_pages += delta; ret = 0; -free: + + spin_unlock(&hugetlb_lock); /* Free the needed pages to the hugetlb pool */ list_for_each_entry_safe(page, tmp, &surplus_list, lru) { if ((--needed) < 0) break; list_del(&page->lru); + /* + * This page is now managed by the hugetlb allocator and has + * no users -- drop the buddy allocator's reference. + */ + put_page_testzero(page); + VM_BUG_ON(page_count(page)); enqueue_huge_page(h, page); } /* Free unnecessary surplus pages to the buddy allocator */ +free: if (!list_empty(&surplus_list)) { - spin_unlock(&hugetlb_lock); list_for_each_entry_safe(page, tmp, &surplus_list, lru) { list_del(&page->lru); - /* - * The page has a reference count of zero already, so - * call free_huge_page directly instead of using - * put_page. This must be done with hugetlb_lock - * unlocked which is safe because free_huge_page takes - * hugetlb_lock before deciding how to free the page. - */ - free_huge_page(page); + put_page(page); } - spin_lock(&hugetlb_lock); } + spin_lock(&hugetlb_lock); return ret; } @@ -1123,7 +1115,6 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, } } - set_page_refcounted(page); set_page_private(page, (unsigned long) mapping); vma_commit_reservation(h, vma, addr); |