linux-kernel - [PATCH v4 08/10] sched/topology: Remove SD

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Message-Id: <20200731115502.12954-9-valentin.schneider@arm.com>
Date:   Fri, 31 Jul 2020 12:55:00 +0100
From:   Valentin Schneider <valentin.schneider@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Peter Zijlstra <peterz@...radead.org>, mingo@...nel.org,
        vincent.guittot@...aro.org, dietmar.eggemann@....com,
        morten.rasmussen@....com, Quentin Perret <qperret@...gle.com>
Subject: [PATCH v4 08/10] sched/topology: Remove SD_SERIALIZE degeneration special case

If there is only a single NUMA node in the system, the only NUMA topology
level that will be generated will be NODE (identity distance), which
doesn't have SD_SERIALIZE.

This means we don't need this special case in sd_parent_degenerate(), as
having the NODE level "naturally" covers it. Thus, remove it.

Suggested-by: Peter Zijlstra <peterz@...radead.org>
Signed-off-by: Valentin Schneider <valentin.schneider@....com>
---
 kernel/sched/topology.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 93a7ff52335b..c6ecc395c76c 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -204,8 +204,6 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
 			    SD_SHARE_PKG_RESOURCES |
 			    SD_OVERLAP |
 			    SD_PREFER_SIBLING);
-		if (nr_node_ids == 1)
-			pflags &= ~SD_SERIALIZE;
 	}
 	if (~cflags & pflags)
 		return 0;
-- 
2.27.0