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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Gabriele Monaco <gmonaco@redhat.com>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Michael Jeanson <mjeanson@efficios.com>,
	Jens Axboe <axboe@kernel.dk>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	"Gautham R. Shenoy" <gautham.shenoy@amd.com>,
	Florian Weimer <fweimer@redhat.com>,
	Tim Chen <tim.c.chen@intel.com>,
	Yury Norov <yury.norov@gmail.com>
Subject: [patch V2 08/20] sched/mmcid: Use cpumask_or_and_calc_weight()
Date: Wed, 22 Oct 2025 14:55:29 +0200 (CEST)	[thread overview]
Message-ID: <20251022110555.901055185@linutronix.de> (raw)
In-Reply-To: <20251022104005.907410538@linutronix.de>

Use cpumask_or_and_calc_weight() instead of cpumask_or() and
cpumask_weight() on the result, which walks the same bitmap twice.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/sched/core.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10375,6 +10375,7 @@ void call_trace_sched_update_nr_running(
 static inline void mm_update_cpus_allowed(struct mm_struct *mm, const struct cpumask *affmsk)
 {
 	struct cpumask *mm_allowed;
+	unsigned int weight;
 
 	if (!mm)
 		return;
@@ -10385,8 +10386,8 @@ static inline void mm_update_cpus_allowe
 	 */
 	guard(raw_spinlock)(&mm->mm_cid.lock);
 	mm_allowed = mm_cpus_allowed(mm);
-	cpumask_or(mm_allowed, mm_allowed, affmsk);
-	WRITE_ONCE(mm->mm_cid.nr_cpus_allowed, cpumask_weight(mm_allowed));
+	weight = cpumask_or_and_calc_weight(mm_allowed, mm_allowed, affmsk);
+	WRITE_ONCE(mm->mm_cid.nr_cpus_allowed, weight);
 }
 
 void sched_mm_cid_exit_signals(struct task_struct *t)


  parent reply	other threads:[~2025-10-22 12:55 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-22 12:55 [patch V2 00/20] sched: Rewrite MM CID management Thomas Gleixner
2025-10-22 12:55 ` [patch V2 01/20] sched/mmcid: Revert the complex " Thomas Gleixner
2025-10-22 12:55 ` [patch V2 02/20] sched/mmcid: Use proper data structures Thomas Gleixner
2025-10-22 12:55 ` [patch V2 03/20] sched/mmcid: Cacheline align MM CID storage Thomas Gleixner
2025-10-22 12:55 ` [patch V2 04/20] sched: Fixup whitespace damage Thomas Gleixner
2025-10-22 12:55 ` [patch V2 05/20] sched/mmcid: Move scheduler code out of global header Thomas Gleixner
2025-10-22 12:55 ` [patch V2 06/20] sched/mmcid: Prevent pointless work in mm_update_cpus_allowed() Thomas Gleixner
2025-10-22 12:55 ` [patch V2 07/20] cpumask: Introduce cpumask_or_and_calc_weight() Thomas Gleixner
2025-10-23 16:37   ` Yury Norov
2025-10-22 12:55 ` Thomas Gleixner [this message]
2025-10-23 16:45   ` [patch V2 08/20] sched/mmcid: Use cpumask_or_and_calc_weight() Yury Norov
2025-10-22 12:55 ` [patch V2 09/20] cpumask: Cache num_possible_cpus() Thomas Gleixner
2025-10-23 16:25   ` Yury Norov
2025-10-22 12:55 ` [patch V2 10/20] sched/mmcid: Convert mm CID mask to a bitmap Thomas Gleixner
2025-10-23 16:46   ` Yury Norov
2025-10-27  5:45   ` Shrikanth Hegde
2025-10-27  8:57     ` Thomas Gleixner
2025-10-22 12:55 ` [patch V2 11/20] signal: Move MMCID exit out of sighand lock Thomas Gleixner
2025-10-22 12:55 ` [patch V2 12/20] sched/mmcid: Move initialization out of line Thomas Gleixner
2025-10-22 12:55 ` [patch V2 13/20] sched/mmcid: Provide precomputed maximal value Thomas Gleixner
2025-10-22 12:55 ` [patch V2 14/20] sched/mmcid: Serialize sched_mm_cid_fork()/exit() with a mutex Thomas Gleixner
2025-10-22 12:55 ` [patch V2 15/20] sched/mmcid: Introduce per task/CPU ownership infrastrcuture Thomas Gleixner
2025-10-22 12:55 ` [patch V2 16/20] sched/mmcid: Provide new scheduler CID mechanism Thomas Gleixner
2025-10-27  5:11   ` Shrikanth Hegde
2025-10-27  8:54     ` Thomas Gleixner
2025-10-22 12:55 ` [patch V2 17/20] sched/mmcid: Provide CID ownership mode fixup functions Thomas Gleixner
2025-10-22 12:55 ` [patch V2 18/20] irqwork: Move data struct to a types header Thomas Gleixner
2025-10-22 12:55 ` [patch V2 19/20] sched/mmcid: Implement deferred mode change Thomas Gleixner
2025-10-22 12:55 ` [patch V2 20/20] sched/mmcid: Switch over to the new mechanism Thomas Gleixner

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