From: Peter Xu <peterx@redhat.com>
To: linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: David Hildenbrand <david@redhat.com>,
Alistair Popple <apopple@nvidia.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Johannes Weiner <hannes@cmpxchg.org>,
John Hubbard <jhubbard@nvidia.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
peterx@redhat.com,
Muhammad Usama Anjum <usama.anjum@collabora.com>,
Hugh Dickins <hughd@google.com>, Mike Rapoport <rppt@kernel.org>
Subject: [PATCH 3/4] mm: Warn for unstable pmd in move_page_tables()
Date: Fri, 2 Jun 2023 19:05:51 -0400 [thread overview]
Message-ID: <20230602230552.350731-4-peterx@redhat.com> (raw)
In-Reply-To: <20230602230552.350731-1-peterx@redhat.com>
We already hold write mmap lock here, not possible to trigger unstable
pmd. Make it a WARN_ON_ONCE instead.
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
mm/mremap.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index da107f2c71bf..9303e4da4e7f 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -544,8 +544,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
old_pmd, new_pmd, need_rmap_locks))
continue;
split_huge_pmd(vma, old_pmd, old_addr);
- if (pmd_trans_unstable(old_pmd))
- continue;
+ /* We're with the mmap write lock, not possible to happen */
+ WARN_ON_ONCE(pmd_trans_unstable(old_pmd));
} else if (IS_ENABLED(CONFIG_HAVE_MOVE_PMD) &&
extent == PMD_SIZE) {
/*
--
2.40.1
next prev parent reply other threads:[~2023-06-02 23:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 23:05 [PATCH 0/4] mm: Fix pmd_trans_unstable() call sites on retry Peter Xu
2023-06-02 23:05 ` [PATCH 1/4] mm/mprotect: Retry on pmd_trans_unstable() Peter Xu
2023-06-03 2:04 ` Yang Shi
2023-06-04 23:58 ` Peter Xu
2023-06-02 23:05 ` [PATCH 2/4] mm/migrate: Unify and retry an unstable pmd when hit Peter Xu
2023-06-02 23:05 ` Peter Xu [this message]
2023-06-02 23:05 ` [PATCH 4/4] mm: Make most walk page paths with pmd_trans_unstable() to retry Peter Xu
2023-06-05 18:46 ` Yang Shi
2023-06-05 19:20 ` Peter Xu
2023-06-06 19:12 ` Yang Shi
2023-06-06 19:59 ` Peter Xu
2023-06-07 13:49 ` [PATCH 0/4] mm: Fix pmd_trans_unstable() call sites on retry Peter Xu
2023-06-07 15:45 ` David Hildenbrand
2023-06-07 16:21 ` Peter Xu
2023-06-07 16:39 ` Yang Shi
2023-06-07 18:22 ` Peter Xu
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