+ mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy.patch added to -mm tree

+ mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: page_alloc: dump migrate-failed pages only at -EBUSY
has been added to the -mm tree.  Its filename is
     mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy.patch

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------------------------------------------------------
From: Minchan Kim <minchan@kernel.org>
Subject: mm: page_alloc: dump migrate-failed pages only at -EBUSY

alloc_contig_dump_pages() aims for helping debugging page migration
failure by elevated page refcount compared to expected_count.  (for the
detail, please look at migrate_page_move_mapping)

However, -ENOMEM is just the case that system is under memory pressure
state, not relevant with page refcount at all.  Thus, the dumping page
list is not helpful for the debugging point of view.

Link: https://lkml.kernel.org/r/YKa2Wyo9xqIErpfa@google.com
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: John Dias <joaodias@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/page_alloc.c~mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy
+++ a/mm/page_alloc.c
@@ -8763,7 +8763,8 @@ static int __alloc_contig_migrate_range(
 
 	lru_cache_enable();
 	if (ret < 0) {
-		alloc_contig_dump_pages(&cc->migratepages);
+		if (ret == -EBUSY)
+			alloc_contig_dump_pages(&cc->migratepages);
 		putback_movable_pages(&cc->migratepages);
 		return ret;
 	}
_

Patches currently in -mm which might be from minchan@kernel.org are

mm-page_alloc-dump-migrate-failed-pages-only-at-ebusy.patch