We should remove the page from the list if we fail with ENOSYS,
since migrate_pages() consider error cases except -ENOMEM and -EAGAIN
as permanent failure and it assumes that the page would be removed from
the list. Without this patch, we could overcount number of failure.

In addition, we should put back the new hugepage if
!hugepage_migration_support(). If not, we would leak hugepage memory.

Acked-by: Christoph Lameter <c...@linux.com>
Reviewed-by: Wanpeng Li <liw...@linux.vnet.ibm.com>
Signed-off-by: Joonsoo Kim <iamjoonsoo....@lge.com>

diff --git a/mm/migrate.c b/mm/migrate.c
index c6ac87a..b1cfd01 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1011,7 +1011,7 @@ static int unmap_and_move_huge_page(new_page_t 
get_new_page,
 {
        int rc = 0;
        int *result = NULL;
-       struct page *new_hpage = get_new_page(hpage, private, &result);
+       struct page *new_hpage;
        struct anon_vma *anon_vma = NULL;
 
        /*
@@ -1021,9 +1021,12 @@ static int unmap_and_move_huge_page(new_page_t 
get_new_page,
         * tables or check whether the hugepage is pmd-based or not before
         * kicking migration.
         */
-       if (!hugepage_migration_support(page_hstate(hpage)))
+       if (!hugepage_migration_support(page_hstate(hpage))) {
+               putback_active_hugepage(hpage);
                return -ENOSYS;
+       }
 
+       new_hpage = get_new_page(hpage, private, &result);
        if (!new_hpage)
                return -ENOMEM;
 
-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to