mm/compaction.c: micro-optimization remove unnecessary branch

The same code can work both for 'zone->compact_considered > defer_limit'
and 'zone->compact_considered >= defer_limit'.  In the latter there is one
branch less which is more effective considering performance.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Link: https://lkml.kernel.org/r/20200913190448.28649-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/compaction.c

@@ -180,11 +180,10 @@ bool compaction_deferred(struct zone *zone, int order)
 		return false;
 
 	/* Avoid possible overflow */
-	if (++zone->compact_considered > defer_limit)
+	if (++zone->compact_considered >= defer_limit) {
 		zone->compact_considered = defer_limit;
-
-	if (zone->compact_considered >= defer_limit)
 		return false;
+	}
 
 	trace_mm_compaction_deferred(zone, order);