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authorBaolin Wang <baolin.wang@linux.alibaba.com>2022-04-28 23:16:09 -0700
committerakpm <akpm@linux-foundation.org>2022-04-28 23:16:09 -0700
commit9c42fe4e30a9b934b1de66c2edca196563221392 (patch)
treec435755b4e49b6fc20b8b66960ec0e608ff08a77
parent4cd614841c06338a087769ee3cfa96718784d1f5 (diff)
mm: migrate: simplify the refcount validation when migrating hugetlb mapping
There is no need to validate the hugetlb page's refcount before trying to freeze the hugetlb page's expected refcount, instead we can just rely on the page_ref_freeze() to simplify the validation. Moreover we are always under the page lock when migrating the hugetlb page mapping, which means nowhere else can remove it from the page cache, so we can remove the xas_load() validation under the i_pages lock. Link: https://lkml.kernel.org/r/eb2fbbeaef2b1714097b9dec457426d682ee0635.1649676424.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Acked-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Alistair Popple <apopple@nvidia.com> Cc: Zi Yan <ziy@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--mm/migrate.c5
1 files changed, 0 insertions, 5 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 35f6416d2953..f97d724b8fc0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -471,11 +471,6 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,
xas_lock_irq(&xas);
expected_count = 2 + page_has_private(page);
- if (page_count(page) != expected_count || xas_load(&xas) != page) {
- xas_unlock_irq(&xas);
- return -EAGAIN;
- }
-
if (!page_ref_freeze(page, expected_count)) {
xas_unlock_irq(&xas);
return -EAGAIN;