From: Miaohe Lin <linmiaohe@huawei.com>
To: <akpm@linux-foundation.org>
Cc: <jglisse@redhat.com>, <shy828301@gmail.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<linmiaohe@huawei.com>
Subject: [PATCH 5/5] mm/migrate.c: fix potential deadlock in NUMA balancing shared exec THP case
Date: Sat, 20 Mar 2021 05:37:01 -0400 [thread overview]
Message-ID: <20210320093701.12829-6-linmiaohe@huawei.com> (raw)
In-Reply-To: <20210320093701.12829-1-linmiaohe@huawei.com>
Since commit c77c5cbafe54 ("mm: migrate: skip shared exec THP for NUMA
balancing"), the NUMA balancing would skip shared exec transhuge page.
But this enhancement is not suitable for transhuge page. Because it's
required that page_mapcount() must be 1 due to no migration pte dance
is done here. On the other hand, the shared exec transhuge page will
leave the migrate_misplaced_page() with pte entry untouched and page
locked. Thus pagefault for NUMA will be triggered again and deadlock
occurs when we start waiting for the page lock held by ourselves.
Fixes: c77c5cbafe54 ("mm: migrate: skip shared exec THP for NUMA balancing")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
mm/migrate.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 3e169b72d7b2..67a941c52b6d 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2192,9 +2192,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
int page_lru = page_is_file_lru(page);
unsigned long start = address & HPAGE_PMD_MASK;
- if (is_shared_exec_page(vma, page))
- goto out;
-
new_page = alloc_pages_node(node,
(GFP_TRANSHUGE_LIGHT | __GFP_THISNODE),
HPAGE_PMD_ORDER);
@@ -2306,7 +2303,6 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
out_unlock:
unlock_page(page);
-out:
put_page(page);
return 0;
}
--
2.19.1
prev parent reply other threads:[~2021-03-20 9:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-20 9:36 [PATCH 0/5] Cleanup and fixup for mm/migrate.c Miaohe Lin
2021-03-20 9:36 ` [PATCH 1/5] mm/migrate.c: remove unnecessary VM_BUG_ON_PAGE on putback_movable_page() Miaohe Lin
2021-03-20 14:11 ` Rafael Aquini
2021-03-22 1:52 ` Miaohe Lin
2021-03-20 9:36 ` [PATCH 2/5] mm/migrate.c: remove unnecessary rc != MIGRATEPAGE_SUCCESS check in 'else' case Miaohe Lin
2021-03-23 10:23 ` David Hildenbrand
2021-03-20 9:36 ` [PATCH 3/5] mm/migrate.c: fix potential indeterminate pte entry in migrate_vma_insert_page() Miaohe Lin
2021-03-23 10:26 ` David Hildenbrand
2021-03-23 11:07 ` Alistair Popple
2021-03-23 11:28 ` Miaohe Lin
2021-03-23 12:15 ` Miaohe Lin
2021-03-23 11:24 ` Miaohe Lin
2021-03-20 9:37 ` [PATCH 4/5] mm/migrate.c: use helper migrate_vma_collect_skip() in migrate_vma_collect_hole() Miaohe Lin
2021-03-23 10:29 ` David Hildenbrand
2021-03-20 9:37 ` Miaohe Lin [this message]
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