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authorBaolin Wang <baolin.wang@linux.alibaba.com>2022-10-24 10:34:21 +0200
committerAndrew Morton <akpm@linux-foundation.org>2022-10-28 22:37:22 +0200
commit03e5f82ea632af329e32ec03d952b2d99497eeaa (patch)
tree962e0a0e67331bb2109565ee8ed5b35a77234cf9 /mm/migrate.c
parentmm/uffd: fix vma check on userfault for wp (diff)
downloadlinux-03e5f82ea632af329e32ec03d952b2d99497eeaa.tar.xz
linux-03e5f82ea632af329e32ec03d952b2d99497eeaa.zip
mm: migrate: fix return value if all subpages of THPs are migrated successfully
During THP migration, if THPs are not migrated but they are split and all subpages are migrated successfully, migrate_pages() will still return the number of THP pages that were not migrated. This will confuse the callers of migrate_pages(). For example, the longterm pinning will failed though all pages are migrated successfully. Thus we should return 0 to indicate that all pages are migrated in this case Link: https://lkml.kernel.org/r/de386aa864be9158d2f3b344091419ea7c38b2f7.1666599848.git.baolin.wang@linux.alibaba.com Fixes: b5bade978e9b ("mm: migrate: fix the return value of migrate_pages()") Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com> Reviewed-by: Alistair Popple <apopple@nvidia.com> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: David Hildenbrand <david@redhat.com> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Zi Yan <ziy@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 1379e1912772..dff333593a8a 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1582,6 +1582,13 @@ out:
*/
list_splice(&ret_pages, from);
+ /*
+ * Return 0 in case all subpages of fail-to-migrate THPs are
+ * migrated successfully.
+ */
+ if (list_empty(from))
+ rc = 0;
+
count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded);
count_vm_events(PGMIGRATE_FAIL, nr_failed_pages);
count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded);