The patch titled
Subject: mm: migrate: do not retry 10 times for the subpages of fail-to-migrate THP
has been added to the -mm mm-unstable branch. Its filename is
mm-migrate-do-not-retry-10-times-for-the-subpages-of-fail-to-migrate-thp.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-migrate-do-not-retry-10-times-for-the-subpages-of-fail-to-migrate-thp.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: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Subject: mm: migrate: do not retry 10 times for the subpages of fail-to-migrate THP
Date: Wed, 17 Aug 2022 16:14:08 +0800
If THP is failed to migrate due to -ENOSYS or -ENOMEM case, the THP will
be split, and the subpages of fail-to-migrate THP will be tried to migrate
again, so we should not account the retry counter in the second loop,
since we already accounted 'nr_thp_failed' in the first loop.
Moreover we also do not need retry 10 times for -EAGAIN case for the
subpages of fail-to-migrate THP in the second loop, since we already
regarded the THP as migration failure, and save some migration time (for
the worst case, will try 512 * 10 times) according to previous discussion
[1].
[1] https://lore.kernel.org/linux-mm/87r13a7n04.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20220817081408.513338-9-ying.huang@xxxxxxxxx
Tested-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
--- a/mm/migrate.c~mm-migrate-do-not-retry-10-times-for-the-subpages-of-fail-to-migrate-thp
+++ a/mm/migrate.c
@@ -1522,7 +1522,7 @@ thp_subpage_migration:
case -EAGAIN:
if (is_thp)
thp_retry++;
- else
+ else if (!no_subpage_counting)
retry++;
nr_retry_pages += nr_subpages;
break;
@@ -1548,8 +1548,7 @@ thp_subpage_migration:
}
}
}
- if (!no_subpage_counting)
- nr_failed += retry;
+ nr_failed += retry;
nr_thp_failed += thp_retry;
nr_failed_pages += nr_retry_pages;
/*
_
Patches currently in -mm which might be from baolin.wang@xxxxxxxxxxxxxxxxx are
mm-migrate-do-not-retry-10-times-for-the-subpages-of-fail-to-migrate-thp.patch
