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From:   Gang Li <ligang.bdlg@bytedance.com>
To:     John Hubbard <jhubbard@nvidia.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Valentin Schneider <vschneid@redhat.com>
Cc:     linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
        Gang Li <ligang.bdlg@bytedance.com>
Subject: [PATCH v6 1/2] sched/numa: use static_branch_inc/dec for sched_numa_balancing
Date:   Wed, 12 Apr 2023 22:10:52 +0800
Message-Id: <20230412141053.59498-1-ligang.bdlg@bytedance.com>
In-Reply-To: <20230412140701.58337-1-ligang.bdlg@bytedance.com>
References: <20230412140701.58337-1-ligang.bdlg@bytedance.com>
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per-process numa balancing use static_branch_inc/dec() to count
how many enables in sched_numa_balancing. So here must be converted
to inc/dec too.

Cc: linux-api@vger.kernel.org
Signed-off-by: Gang Li <ligang.bdlg@bytedance.com>
Acked-by: John Hubbard <jhubbard@nvidia.com>
---
 kernel/sched/core.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 94be4eebfa53..99cc1d5821a1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4501,21 +4501,15 @@ DEFINE_STATIC_KEY_FALSE(sched_numa_balancing);
 
 int sysctl_numa_balancing_mode;
 
-static void __set_numabalancing_state(bool enabled)
-{
-	if (enabled)
-		static_branch_enable(&sched_numa_balancing);
-	else
-		static_branch_disable(&sched_numa_balancing);
-}
-
 void set_numabalancing_state(bool enabled)
 {
-	if (enabled)
+	if (enabled) {
 		sysctl_numa_balancing_mode = NUMA_BALANCING_NORMAL;
-	else
+		static_branch_enable(&sched_numa_balancing);
+	} else {
 		sysctl_numa_balancing_mode = NUMA_BALANCING_DISABLED;
-	__set_numabalancing_state(enabled);
+		static_branch_disable(&sched_numa_balancing);
+	}
 }
 
 #ifdef CONFIG_PROC_SYSCTL
@@ -4549,8 +4543,14 @@ static int sysctl_numa_balancing(struct ctl_table *table, int write,
 		if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING) &&
 		    (state & NUMA_BALANCING_MEMORY_TIERING))
 			reset_memory_tiering();
-		sysctl_numa_balancing_mode = state;
-		__set_numabalancing_state(state);
+		if (sysctl_numa_balancing_mode != state) {
+			if (state == NUMA_BALANCING_DISABLED)
+				static_branch_dec(&sched_numa_balancing);
+			else if (sysctl_numa_balancing_mode == NUMA_BALANCING_DISABLED)
+				static_branch_inc(&sched_numa_balancing);
+
+			sysctl_numa_balancing_mode = state;
+		}
 	}
 	return err;
 }
-- 
2.20.1