mm, compaction: check if a page has been captured before draining PCP pages

If a page has been captured then draining is unnecssary so check first for
a captured page.

Link: https://lkml.kernel.org/r/20230125134434.18017-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
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>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/compaction.c b/mm/compaction.c
index 28a9596..a865599 100644 (file)
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -2439,6 +2439,12 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
                        }
                }
 
+               /* Stop if a page has been captured */
+               if (capc && capc->page) {
+                       ret = COMPACT_SUCCESS;
+                       break;
+               }
+
 check_drain:
                /*
                 * Has the migration scanner moved away from the previous
@@ -2457,12 +2463,6 @@ check_drain:
                                last_migrated_pfn = 0;
                        }
                }
-
-               /* Stop if a page has been captured */
-               if (capc && capc->page) {
-                       ret = COMPACT_SUCCESS;
-                       break;
-               }
        }
 
 out: