From 7dcd6204160ee147fa902d30657c4fc7e16d5a4e Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 17 Apr 2023 07:59:29 +0800 Subject: [PATCH] migrate_pages_batch: fix statistics for longterm pin retry 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" Reviewed-by: Baolin Wang Cc: Alistair Popple Cc: David Hildenbrand Cc: Yang Shi Cc: Zi Yan Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/migrate.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/migrate.c b/mm/migrate.c index 8393f4a935a9..209078154a46 100644 --- 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; } }