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From: Steven Rostedt <rostedt@goodmis.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Wander Lairson Costa <wander@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
	Ian Rogers <irogers@google.com>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Will Deacon <will@kernel.org>, Waiman Long <longman@redhat.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Kefeng Wang <wangkefeng.wang@huawei.com>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Kees Cook <keescook@chromium.org>,
	Christian Brauner <brauner@kernel.org>,
	Andrei Vagin <avagin@gmail.com>,
	Shakeel Butt <shakeelb@google.com>,
	open list <linux-kernel@vger.kernel.org>,
	"open list:PERFORMANCE EVENTS SUBSYSTEM" 
	<linux-perf-users@vger.kernel.org>, Hu Chunyu <chuhu@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v6 2/3] sched/task: Add the put_task_struct_atomic_safe() function
Date: Mon, 24 Apr 2023 16:34:38 -0400	[thread overview]
Message-ID: <20230424163438.06cc880e@rorschach.local.home> (raw)
In-Reply-To: <105084b0-9d65-4896-97e4-35ef3c6f1fae@paulmck-laptop>

On Mon, 24 Apr 2023 11:52:52 -0700
"Paul E. McKenney" <paulmck@kernel.org> wrote:

> > softirqs execute in thread context in PREEMPT_RT. We are good here.  
> 
> So the sleeping lock is a spinlock rather than (say) a mutex?

local_bh_disable() on RT basically turns into:

	local_lock(&softirq_ctrl.lock);
	rcu_read_lock();

Which grabs a per CPU mutex that is taken by softirqs, and also calls
rcu_read_lock(). This allows bottom halves to still run as threads but
maintain the same synchronization as they do on mainline.

-- Steve

  parent reply	other threads:[~2023-04-24 20:34 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-14 12:55 [PATCH v6 0/3] Introduce put_task_struct_atomic_sleep() Wander Lairson Costa
2023-04-14 12:55 ` [PATCH v6 1/3] sched/core: warn on call put_task_struct in invalid context Wander Lairson Costa
2023-04-14 12:55 ` [PATCH v6 2/3] sched/task: Add the put_task_struct_atomic_safe() function Wander Lairson Costa
2023-04-17 18:51   ` Waiman Long
2023-04-18 14:18     ` Wander Lairson Costa
2023-04-18 14:26       ` Waiman Long
2023-04-24 18:09   ` Paul E. McKenney
2023-04-24 18:43     ` Wander Lairson Costa
2023-04-24 18:52       ` Paul E. McKenney
2023-04-24 20:34         ` Wander Lairson Costa
2023-04-24 21:54           ` Paul E. McKenney
2023-04-24 20:34         ` Steven Rostedt [this message]
2023-04-14 12:55 ` [PATCH v6 3/3] treewide: replace put_task_struct() witht the atomic safe version Wander Lairson Costa
2023-04-17 18:53   ` Waiman Long

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