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From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Naoya Horiguchi <nao.horiguchi@gmail.com>,
	<stable@vger.kernel.org>
Subject: [PATCH v3 5/5] mm/hugetlb: add migration entry check in __unmap_hugepage_range
Date: Mon, 15 Sep 2014 18:39:59 -0400	[thread overview]
Message-ID: <1410820799-27278-6-git-send-email-n-horiguchi@ah.jp.nec.com> (raw)
In-Reply-To: <1410820799-27278-1-git-send-email-n-horiguchi@ah.jp.nec.com>

If __unmap_hugepage_range() tries to unmap the address range over which
hugepage migration is on the way, we get the wrong page because pte_page()
doesn't work for migration entries. This patch simply clears the pte for
migration entries as we do for hwpoison entries.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>  # [2.6.36+]
---
ChangeLog v4:
- check hwpoisoned hugepage and migrating hugepage with the same check
  instead of doing separately
---
 mm/hugetlb.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git mmotm-2014-09-09-14-42.orig/mm/hugetlb.c mmotm-2014-09-09-14-42/mm/hugetlb.c
index 461ee1e10067..1ecb625bc498 100644
--- mmotm-2014-09-09-14-42.orig/mm/hugetlb.c
+++ mmotm-2014-09-09-14-42/mm/hugetlb.c
@@ -2653,9 +2653,10 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			goto unlock;
 
 		/*
-		 * HWPoisoned hugepage is already unmapped and dropped reference
+		 * Migrating hugepage or HWPoisoned hugepage is already
+		 * unmapped and its refcount is dropped, so just clear pte here.
 		 */
-		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
+		if (unlikely(!pte_present(pte))) {
 			huge_pte_clear(mm, address, ptep);
 			goto unlock;
 		}
-- 
1.9.3


WARNING: multiple messages have this Message-ID (diff)
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Naoya Horiguchi <nao.horiguchi@gmail.com>,
	stable@vger.kernel.org
Subject: [PATCH v3 5/5] mm/hugetlb: add migration entry check in __unmap_hugepage_range
Date: Mon, 15 Sep 2014 18:39:59 -0400	[thread overview]
Message-ID: <1410820799-27278-6-git-send-email-n-horiguchi@ah.jp.nec.com> (raw)
In-Reply-To: <1410820799-27278-1-git-send-email-n-horiguchi@ah.jp.nec.com>

If __unmap_hugepage_range() tries to unmap the address range over which
hugepage migration is on the way, we get the wrong page because pte_page()
doesn't work for migration entries. This patch simply clears the pte for
migration entries as we do for hwpoison entries.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>  # [2.6.36+]
---
ChangeLog v4:
- check hwpoisoned hugepage and migrating hugepage with the same check
  instead of doing separately
---
 mm/hugetlb.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git mmotm-2014-09-09-14-42.orig/mm/hugetlb.c mmotm-2014-09-09-14-42/mm/hugetlb.c
index 461ee1e10067..1ecb625bc498 100644
--- mmotm-2014-09-09-14-42.orig/mm/hugetlb.c
+++ mmotm-2014-09-09-14-42/mm/hugetlb.c
@@ -2653,9 +2653,10 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 			goto unlock;
 
 		/*
-		 * HWPoisoned hugepage is already unmapped and dropped reference
+		 * Migrating hugepage or HWPoisoned hugepage is already
+		 * unmapped and its refcount is dropped, so just clear pte here.
 		 */
-		if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
+		if (unlikely(!pte_present(pte))) {
 			huge_pte_clear(mm, address, ptep);
 			goto unlock;
 		}
-- 
1.9.3

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  parent reply	other threads:[~2014-09-15 22:42 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-15 22:39 [PATCH 0/5] hugepage migration fixes (v4) Naoya Horiguchi
2014-09-15 22:39 ` Naoya Horiguchi
2014-09-15 22:39 ` [PATCH v3 1/5] mm/hugetlb: reduce arch dependent code around follow_huge_* Naoya Horiguchi
2014-09-15 22:39   ` Naoya Horiguchi
2014-09-16 15:56   ` Naoya Horiguchi
2014-09-16 15:56     ` Naoya Horiguchi
2014-09-15 22:39 ` [PATCH v3 2/5] mm/hugetlb: take page table lock in follow_huge_pmd() Naoya Horiguchi
2014-09-15 22:39   ` Naoya Horiguchi
2014-09-30  4:32   ` Hugh Dickins
2014-09-30  4:32     ` Hugh Dickins
2014-10-07 16:56     ` Naoya Horiguchi
2014-10-07 16:56       ` Naoya Horiguchi
2014-09-15 22:39 ` [PATCH v3 3/5] mm/hugetlb: fix getting refcount 0 page in hugetlb_fault() Naoya Horiguchi
2014-09-15 22:39   ` Naoya Horiguchi
2014-09-30  4:52   ` Hugh Dickins
2014-09-30  4:52     ` Hugh Dickins
2014-10-07 16:56     ` Naoya Horiguchi
2014-10-07 16:56       ` Naoya Horiguchi
2014-09-15 22:39 ` [PATCH v3 4/5] mm/hugetlb: add migration/hwpoisoned entry check in hugetlb_change_protection Naoya Horiguchi
2014-09-15 22:39   ` Naoya Horiguchi
2014-09-15 22:39 ` Naoya Horiguchi [this message]
2014-09-15 22:39   ` [PATCH v3 5/5] mm/hugetlb: add migration entry check in __unmap_hugepage_range Naoya Horiguchi

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