From: "tip-bot2 for Yejune Deng" <tip-bot2@linutronix.de>
To: linux-tip-commits@vger.kernel.org
Cc: Valentin Schneider <valentin.schneider@arm.com>,
Yejune Deng <yejune.deng@gmail.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: [tip: sched/core] lib/smp_processor_id: Use is_percpu_thread() instead of nr_cpus_allowed
Date: Wed, 19 May 2021 08:09:06 -0000 [thread overview]
Message-ID: <162141174613.29796.12436906474538112691.tip-bot2@tip-bot2> (raw)
In-Reply-To: <20210510151024.2448573-3-valentin.schneider@arm.com>
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 0019699518cc026b5bd912425be8e424843d5b33
Gitweb: https://git.kernel.org/tip/0019699518cc026b5bd912425be8e424843d5b33
Author: Yejune Deng <yejune.deng@gmail.com>
AuthorDate: Mon, 10 May 2021 16:10:24 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Tue, 18 May 2021 12:53:54 +02:00
lib/smp_processor_id: Use is_percpu_thread() instead of nr_cpus_allowed
is_percpu_thread() more elegantly handles SMP vs UP, and further checks the
presence of PF_NO_SETAFFINITY. This lets us catch cases where
check_preemption_disabled() can race with a concurrent sched_setaffinity().
[Amended changelog]
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210510151024.2448573-3-valentin.schneider@arm.com
---
lib/smp_processor_id.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index 1c1dbd3..046ac62 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -19,11 +19,7 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
if (irqs_disabled())
goto out;
- /*
- * Kernel threads bound to a single CPU can safely use
- * smp_processor_id():
- */
- if (current->nr_cpus_allowed == 1)
+ if (is_percpu_thread())
goto out;
#ifdef CONFIG_SMP
next prev parent reply other threads:[~2021-05-19 8:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-10 15:10 [PATCH 0/2] sched: Address idle task vs pcpu kthread checks Valentin Schneider
2021-05-10 15:10 ` [PATCH 1/2] sched: Make the idle task quack like a per-CPU kthread Valentin Schneider
2021-05-10 15:57 ` Valentin Schneider
2021-05-11 7:32 ` Ingo Molnar
2021-05-11 9:33 ` Valentin Schneider
2021-05-19 8:09 ` [tip: sched/core] " tip-bot2 for Valentin Schneider
2021-05-10 15:10 ` [PATCH 2/2] lib/smp_processor_id: Use is_percpu_thread() instead of nr_cpus_allowed Valentin Schneider
2021-05-19 8:09 ` tip-bot2 for Yejune Deng [this message]
2021-05-19 9:02 ` [tip: sched/core] " tip-bot2 for Yejune Deng
2021-05-31 10:21 ` [PATCH] sched,init: Fix DEBUG_PREEMPT vs early boot Peter Zijlstra
2021-06-01 11:54 ` Valentin Schneider
2021-06-01 14:04 ` [tip: sched/core] " tip-bot2 for Peter Zijlstra
2021-05-12 11:00 ` [PATCH 0/2] sched: Address idle task vs pcpu kthread checks Peter Zijlstra
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