The patch titled
Subject: migrate_pages_batch: fix statistics for longterm pin retry
has been added to the -mm mm-unstable branch. Its filename is
migrate_pages_batch-fix-statistics-for-longterm-pin-retry.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/migrate_pages_batch-fix-statistics-for-longterm-pin-retry.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Huang Ying <ying.huang@xxxxxxxxx>
Subject: migrate_pages_batch: fix statistics for longterm pin retry
Date: Mon, 17 Apr 2023 07:59:29 +0800
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@xxxxxxxxx
Fixes: fd4a7ac32918 ("mm: migrate: try again if THP split is failed due to page refcnt")
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/migrate.c~migrate_pages_batch-fix-statistics-for-longterm-pin-retry
+++ a/mm/migrate.c
@@ -1710,6 +1710,9 @@ static int migrate_pages_batch(struct li
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;
}
}
_
Patches currently in -mm which might be from ying.huang@xxxxxxxxx are
migrate_pages_batch-fix-statistics-for-longterm-pin-retry.patch
