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From: Andrea Arcangeli <aarcange@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Alex Williamson <alex.williamson@redhat.com>,
	"Kirill A. Shutemov" <kirill@shutemov.name>
Subject: [PATCH 3/3] mm: thp: split_huge_pmd_address() comment improvement
Date: Fri,  6 May 2016 17:04:00 +0200	[thread overview]
Message-ID: <1462547040-1737-4-git-send-email-aarcange@redhat.com> (raw)
In-Reply-To: <1462547040-1737-1-git-send-email-aarcange@redhat.com>

Comment is partly wrong, this improves it by including the case of
split_huge_pmd_address() called by try_to_unmap_one if
TTU_SPLIT_HUGE_PMD is set.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
---
 mm/huge_memory.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 9086793..1fbe13d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3031,8 +3031,10 @@ void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
 		return;
 
 	/*
-	 * Caller holds the mmap_sem write mode, so a huge pmd cannot
-	 * materialize from under us.
+	 * Caller holds the mmap_sem write mode or the anon_vma lock,
+	 * so a huge pmd cannot materialize from under us (khugepaged
+	 * holds both the mmap_sem write mode and the anon_vma lock
+	 * write mode).
 	 */
 	__split_huge_pmd(vma, pmd, address, freeze);
 }

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  parent reply	other threads:[~2016-05-06 15:04 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-06 15:03 [PATCH 0/3] mm: thp: mapcount updates Andrea Arcangeli
2016-05-06 15:03 ` [PATCH 1/3] mm: thp: calculate the mapcount correctly for THP pages during WP faults Andrea Arcangeli
2016-05-06 22:10   ` Alex Williamson
2016-05-09 22:26   ` Andrew Morton
2016-05-10 19:21   ` [PATCH 1/1] " Andrea Arcangeli
2016-05-11 21:26     ` [1/1] " Mike Marciniszyn
2016-05-12 16:32     ` [PATCH 1/1] " Andrea Arcangeli
2016-05-12 18:48       ` [1/1] " Mike Marciniszyn
2016-05-06 15:03 ` [PATCH 2/3] mm: thp: microoptimize compound_mapcount() Andrea Arcangeli
2016-05-06 17:33   ` Kirill A. Shutemov
2016-05-06 15:04 ` Andrea Arcangeli [this message]
2016-05-06 17:33   ` [PATCH 3/3] mm: thp: split_huge_pmd_address() comment improvement Kirill A. Shutemov

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