linux-kernel - [PATCH] mm/compaction.c: micro-optimization remove unnecessary branch

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Message-Id: <20200913190448.28649-1-mateusznosek0@gmail.com>
Date:   Sun, 13 Sep 2020 21:04:48 +0200
From:   mateusznosek0@...il.com
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     Mateusz Nosek <mateusznosek0@...il.com>, akpm@...ux-foundation.org
Subject: [PATCH] mm/compaction.c: micro-optimization remove unnecessary branch

From: Mateusz Nosek <mateusznosek0@...il.com>

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@...il.com>
---
 mm/compaction.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 176dcded298e..6c63844fc061 100644
--- a/mm/compaction.c
+++ b/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);
 
-- 
2.20.1