Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 09 Sep 2022 14:00:17 -0000
From:   "tip-bot2 for Chengming Zhou" <tip-bot2@linutronix.de>
Sender: tip-bot2@linutronix.de
Reply-to: linux-kernel@vger.kernel.org
To:     linux-tip-commits@vger.kernel.org
Subject: [tip: sched/psi] sched/psi: Save percpu memory when !psi_cgroups_enabled
Cc:     Chengming Zhou <zhouchengming@bytedance.com>,
        "Peter Zijlstra (Intel)" <peterz@infradead.org>,
        Johannes Weiner <hannes@cmpxchg.org>, x86@kernel.org,
        linux-kernel@vger.kernel.org
In-Reply-To: <20220825164111.29534-4-zhouchengming@bytedance.com>
References: <20220825164111.29534-4-zhouchengming@bytedance.com>
MIME-Version: 1.0
Message-ID: <166273201708.401.11559207827527564278.tip-bot2@tip-bot2>
Robot-ID: <tip-bot2@linutronix.de>
Robot-Unsubscribe: Contact <mailto:tglx@linutronix.de> to get blacklisted from these emails
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
Precedence: bulk

The following commit has been merged into the sched/psi branch of tip:

Commit-ID:     e2ad8ab04c5cdfc8dc2f382c45d248ab01dee991
Gitweb:        https://git.kernel.org/tip/e2ad8ab04c5cdfc8dc2f382c45d248ab01dee991
Author:        Chengming Zhou <zhouchengming@bytedance.com>
AuthorDate:    Fri, 26 Aug 2022 00:41:04 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Fri, 09 Sep 2022 11:08:31 +02:00

sched/psi: Save percpu memory when !psi_cgroups_enabled

We won't use cgroup psi_group when !psi_cgroups_enabled, so don't
bother to alloc percpu memory and init for it.

Also don't need to migrate task PSI stats between cgroups in
cgroup_move_task().

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20220825164111.29534-4-zhouchengming@bytedance.com
---
 kernel/sched/psi.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 39463dc..77d53c0 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -201,6 +201,7 @@ void __init psi_init(void)
 {
 	if (!psi_enable) {
 		static_branch_enable(&psi_disabled);
+		static_branch_disable(&psi_cgroups_enabled);
 		return;
 	}
 
@@ -950,7 +951,7 @@ void psi_memstall_leave(unsigned long *flags)
 #ifdef CONFIG_CGROUPS
 int psi_cgroup_alloc(struct cgroup *cgroup)
 {
-	if (static_branch_likely(&psi_disabled))
+	if (!static_branch_likely(&psi_cgroups_enabled))
 		return 0;
 
 	cgroup->psi = kzalloc(sizeof(struct psi_group), GFP_KERNEL);
@@ -968,7 +969,7 @@ int psi_cgroup_alloc(struct cgroup *cgroup)
 
 void psi_cgroup_free(struct cgroup *cgroup)
 {
-	if (static_branch_likely(&psi_disabled))
+	if (!static_branch_likely(&psi_cgroups_enabled))
 		return;
 
 	cancel_delayed_work_sync(&cgroup->psi->avgs_work);
@@ -996,7 +997,7 @@ void cgroup_move_task(struct task_struct *task, struct css_set *to)
 	struct rq_flags rf;
 	struct rq *rq;
 
-	if (static_branch_likely(&psi_disabled)) {
+	if (!static_branch_likely(&psi_cgroups_enabled)) {
 		/*
 		 * Lame to do this here, but the scheduler cannot be locked
 		 * from the outside, so we move cgroups from inside sched/.