6.1-stable review patch. If anyone has any objections, please let me know.
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From: Huang Ying ying.huang@intel.com
commit 851ae6424697d1c4f085cb878c88168923ebcad1 upstream.
In commit fd4a7ac32918 ("mm: migrate: try again if THP split is failed due to page refcnt"), if the THP splitting fails due to page reference count, we will retry to improve migration successful rate. But the failed splitting is counted as migration failure and migration retry, which will cause duplicated failure counting. So, in this patch, this is fixed via undoing the failure counting if we decide to retry. The patch is tested via failure injection.
Link: https://lkml.kernel.org/r/20230416235929.1040194-1-ying.huang@intel.com Fixes: fd4a7ac32918 ("mm: migrate: try again if THP split is failed due to page refcnt") Signed-off-by: "Huang, Ying" ying.huang@intel.com Reviewed-by: Baolin Wang baolin.wang@linux.alibaba.com Cc: Alistair Popple apopple@nvidia.com Cc: David Hildenbrand david@redhat.com Cc: Yang Shi shy828301@gmail.com Cc: Zi Yan ziy@nvidia.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/migrate.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/mm/migrate.c +++ b/mm/migrate.c @@ -1700,6 +1700,9 @@ split_folio_migration: large_retry++; thp_retry += is_thp; nr_retry_pages += nr_pages; + /* Undo duplicated failure counting. */ + nr_large_failed--; + stats->nr_thp_failed -= is_thp; break; } }