| From: Mel Gorman <mgorman@techsingularity.net> |
| Subject: mm: compaction: only force pageblock scan completion when skip hints are obeyed |
| Date: Mon, 15 May 2023 12:33:42 +0100 |
| |
| fast_find_migrateblock relies on skip hints to avoid rescanning a recently |
| selected pageblock but compact_zone() only forces the pageblock scan |
| completion to set the skip hint if in direct compaction. While this |
| prevents direct compaction repeatedly scanning a subset of blocks due to |
| fast_find_migrateblock(), it does not prevent proactive compaction, node |
| compaction and kcompactd encountering the same problem described in commit |
| cfccd2e63e7e ("mm, compaction: finish pageblocks on complete migration |
| failure"). |
| |
| Force the scan completion of a pageblock to set the skip hint if skip |
| hints are obeyed to prevent fast_find_migrateblock() repeatedly selecting |
| a subset of pageblocks. |
| |
| Link: https://lkml.kernel.org/r/20230515113344.6869-3-mgorman@techsingularity.net |
| Signed-off-by: Mel Gorman <mgorman@techsingularity.net> |
| Suggested-by: Vlastimil Babka <vbabka@suse.cz> |
| Tested-by: Raghavendra K T <raghavendra.kt@amd.com> |
| Acked-by: Vlastimil Babka <vbabka@suse.cz> |
| Cc: Chuyi Zhou <zhouchuyi@bytedance.com> |
| Cc: Jiri Slaby <jirislaby@kernel.org> |
| Cc: Maxim Levitsky <mlevitsk@redhat.com> |
| Cc: Michal Hocko <mhocko@kernel.org> |
| Cc: Paolo Bonzini <pbonzini@redhat.com> |
| Cc: Pedro Falcato <pedro.falcato@gmail.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| --- |
| |
| mm/compaction.c | 5 +++-- |
| 1 file changed, 3 insertions(+), 2 deletions(-) |
| |
| --- a/mm/compaction.c~mm-compaction-only-force-pageblock-scan-completion-when-skip-hints-are-obeyed |
| +++ a/mm/compaction.c |
| @@ -2457,7 +2457,8 @@ rescan: |
| } |
| /* |
| * If an ASYNC or SYNC_LIGHT fails to migrate a page |
| - * within the current order-aligned block, scan the |
| + * within the current order-aligned block and |
| + * fast_find_migrateblock may be used then scan the |
| * remainder of the pageblock. This will mark the |
| * pageblock "skip" to avoid rescanning in the near |
| * future. This will isolate more pages than necessary |
| @@ -2466,7 +2467,7 @@ rescan: |
| * recently partially scanned. |
| */ |
| if (!pageblock_aligned(cc->migrate_pfn) && |
| - cc->direct_compaction && !cc->finish_pageblock && |
| + !cc->ignore_skip_hint && !cc->finish_pageblock && |
| (cc->mode < MIGRATE_SYNC)) { |
| cc->finish_pageblock = true; |
| |
| _ |
