From: Nico Pache <npache@redhat.com>
To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Cc: Nico Pache <npache@redhat.com>,
David Hildenbrand <david@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Lorenzo Stoakes <ljs@kernel.org>, Zi Yan <ziy@nvidia.com>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"Liam R. Howlett" <liam@infradead.org>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
Usama Arif <usama.arif@linux.dev>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>, Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>
Subject: [PATCH 6/8] mm/khugepaged: unmap pte before releasing vma write lock
Date: Mon, 6 Jul 2026 09:44:53 -0600 [thread overview]
Message-ID: <20260706154500.39178-7-npache@redhat.com> (raw)
In-Reply-To: <20260706154500.39178-1-npache@redhat.com>
We are currently dropping the anon_vma write lock before unmapping the
PTE. Although this is safe, due to us still holding the mmap_write_lock,
its safer and less confusing to switch the order of these two operations.
Suggested-by: David Hildenbrand <david@kernel.org>
Signed-off-by: Nico Pache <npache@redhat.com>
---
mm/khugepaged.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index c4ea2dc1591b..3c6f1254deca 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1548,10 +1548,10 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long s
result = SCAN_SUCCEED;
out_up_write:
- if (anon_vma_locked)
- anon_vma_unlock_write(vma->anon_vma);
if (pte)
pte_unmap(pte);
+ if (anon_vma_locked)
+ anon_vma_unlock_write(vma->anon_vma);
mmap_write_unlock(mm);
out_nolock:
if (folio)
--
2.54.0
next prev parent reply other threads:[~2026-07-06 15:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-06 15:44 [PATCH 0/8] mm/khugepaged: several cleanups Nico Pache
2026-07-06 15:44 ` [PATCH 1/8] mm/khugepaged: refactor per-scan state clearing into collapse_control_init_scan() Nico Pache
2026-07-06 17:07 ` Usama Arif
2026-07-06 17:12 ` Nico Pache
2026-07-06 15:44 ` [PATCH 2/8] mm/khugepaged: extract young page check into collapse_is_young() helper Nico Pache
2026-07-06 17:09 ` Usama Arif
2026-07-06 15:44 ` [PATCH 3/8] mm/khugepaged: introduce a count_collapse_event() helper Nico Pache
2026-07-06 17:10 ` Usama Arif
2026-07-06 15:44 ` [PATCH 4/8] mm/khugepaged: fix outdated comments Nico Pache
2026-07-06 17:13 ` Usama Arif
2026-07-06 15:44 ` [PATCH 5/8] mm/khugepaged: Refactor the PTE state checks into a helper Nico Pache
2026-07-06 16:35 ` Nico Pache
2026-07-06 17:48 ` Usama Arif
2026-07-06 18:29 ` Nico Pache
2026-07-06 15:44 ` Nico Pache [this message]
2026-07-06 19:34 ` [PATCH 6/8] mm/khugepaged: unmap pte before releasing vma write lock Usama Arif
2026-07-06 15:44 ` [PATCH 7/8] mm/khugepaged: clarify a comment regarding max_ptes_none check Nico Pache
2026-07-06 19:35 ` Usama Arif
2026-07-06 15:44 ` [PATCH 8/8] mm: Documentation: clarify where the mTHP stats live Nico Pache
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