From 07443a85ad90c7b62fbe11dcd3d6a1de1e10516f Mon Sep 17 00:00:00 2001
From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Date: Wed, 11 Sep 2013 14:21:58 -0700
Subject: [PATCH] mm, hugetlb: return a reserved page to a reserved pool if
failed
If we fail with a reserved page, just calling put_page() is not
sufficient, because put_page() invoke free_huge_page() at last step and it
doesn't know whether a page comes from a reserved pool or not. So it
doesn't do anything related to reserved count. This makes reserve count
lower than how we need, because reserve count already decrease in
dequeue_huge_page_vma(). This patch fix this situation.
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: 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 | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5bf6468a8862..06315560bd23 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -572,6 +572,7 @@ static struct page *dequeue_huge_page_vma(struct hstate *h,
if (!vma_has_reserves(vma, chg))
break;
+ SetPagePrivate(page);
h->resv_huge_pages--;
break;
}
@@ -629,15 +630,20 @@ static void free_huge_page(struct page *page)
int nid = page_to_nid(page);
struct hugepage_subpool *spool =
(struct hugepage_subpool *)page_private(page);
+ bool restore_reserve;
set_page_private(page, 0);
page->mapping = NULL;
BUG_ON(page_count(page));
BUG_ON(page_mapcount(page));
+ restore_reserve = PagePrivate(page);
spin_lock(&hugetlb_lock);
hugetlb_cgroup_uncharge_page(hstate_index(h),
pages_per_huge_page(h), page);
+ if (restore_reserve)
+ h->resv_huge_pages++;
+
if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
/* remove the page from active list */
list_del(&page->lru);
@@ -2636,6 +2642,8 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
spin_lock(&mm->page_table_lock);
ptep = huge_pte_offset(mm, address & huge_page_mask(h));
if (likely(pte_same(huge_ptep_get(ptep), pte))) {
+ ClearPagePrivate(new_page);
+
/* Break COW */
huge_ptep_clear_flush(vma, address, ptep);
set_huge_pte_at(mm, address, ptep,
@@ -2747,6 +2755,7 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto retry;
goto out;
}
+ ClearPagePrivate(page);
spin_lock(&inode->i_lock);
inode->i_blocks += blocks_per_huge_page(h);
@@ -2793,8 +2802,10 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
if (!huge_pte_none(huge_ptep_get(ptep)))
goto backout;
- if (anon_rmap)
+ if (anon_rmap) {
+ ClearPagePrivate(page);
hugepage_add_new_anon_rmap(page, vma, address);
+ }
else
page_dup_rmap(page);
new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
--
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