From: Sebastian Siewior <bigeasy@linutronix.de>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: Anna-Maria Behnsen <anna-maria@linutronix.de>,
linux-kernel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>,
John Stultz <jstultz@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
Eric Dumazet <edumazet@google.com>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Arjan van de Ven <arjan@infradead.org>,
"Paul E . McKenney" <paulmck@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Rik van Riel <riel@surriel.com>,
Steven Rostedt <rostedt@goodmis.org>,
Giovanni Gherdovich <ggherdovich@suse.cz>,
Lukasz Luba <lukasz.luba@arm.com>,
"Gautham R . Shenoy" <gautham.shenoy@amd.com>
Subject: Re: [PATCH v6 19/21] timer: Implement the hierarchical pull model
Date: Tue, 16 May 2023 11:37:15 +0200 [thread overview]
Message-ID: <20230516093715.cE8LUUcB@linutronix.de> (raw)
In-Reply-To: <ZGNL427cvjGQ-7dY@localhost.localdomain>
On 2023-05-16 11:24:51 [+0200], Frederic Weisbecker wrote:
> > This looks okay. I wouldn't suggest to hold the timer_base::lock or
> > tmigr_cpu::lock longer than needed. Both can be acquired independently
> > cross CPU and have explicit locking order. So it is fine.
>
>
> LOCK(A)
> LOCK(B)
> UNLOCK(A)
> UNLOCK(B)
>
>
> Cross rhymes aren't pretty in locking. They don't make the review smooth
> but yeah it's not incorrect either. And since I don't have a better way to
> propose...
tmigr_cpu::lock is required longer than timer_base::lock. You can't
acquire tmigr_cpu::lock -> timer_base::lock due to lock ordering.
So you follow the lock order, acquire what needed, drop everything else
to lower lock contention for others.
> > > Thanks,
> > >
> > > Anna-Maria
Sebastian
next prev parent reply other threads:[~2023-05-16 9:37 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-10 7:27 [PATCH v6 00/21] timer: Move from a push remote at enqueue to a pull at expiry model Anna-Maria Behnsen
2023-05-10 7:27 ` [PATCH v6 01/21] tick-sched: Warn when next tick seems to be in the past Anna-Maria Behnsen
2023-05-10 7:27 ` [PATCH v6 02/21] timer: Do not IPI for deferrable timers Anna-Maria Behnsen
2023-05-10 7:27 ` [PATCH v6 03/21] timer: Add comment to get_next_timer_interrupt() description Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 04/21] timer: Move store of next event into __next_timer_interrupt() Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 05/21] timer: Split next timer interrupt logic Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 06/21] timer: Rework idle logic Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 07/21] timers: Introduce add_timer() variants which modify timer flags Anna-Maria Behnsen
2023-06-05 21:43 ` Frederic Weisbecker
2023-05-10 7:28 ` [PATCH v6 08/21] workqueue: Use global variant for add_timer() Anna-Maria Behnsen
2023-05-10 19:30 ` Tejun Heo
2023-06-05 22:16 ` Frederic Weisbecker
2023-05-10 7:28 ` [PATCH v6 09/21] timer: add_timer_on(): Make sure TIMER_PINNED flag is set Anna-Maria Behnsen
2023-06-05 22:12 ` Frederic Weisbecker
2023-05-10 7:28 ` [PATCH v6 10/21] timers: Ease code in run_local_timers() Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 11/21] timers: Create helper function to forward timer base clk Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 12/21] timer: Keep the pinned timers separate from the others Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 13/21] timer: Retrieve next expiry of pinned/non-pinned timers separately Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 14/21] timer: Split out "get next timer interrupt" functionality Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 15/21] timer: Add get next timer interrupt functionality for remote CPUs Anna-Maria Behnsen
2023-05-10 10:16 ` Frederic Weisbecker
2023-05-11 13:06 ` Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 16/21] timer: Restructure internal locking Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 17/21] timer: Check if timers base is handled already Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 18/21] tick/sched: Split out jiffies update helper function Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 19/21] timer: Implement the hierarchical pull model Anna-Maria Behnsen
2023-05-10 10:32 ` Frederic Weisbecker
2023-05-15 10:19 ` Sebastian Siewior
2023-05-15 10:50 ` Anna-Maria Behnsen
2023-05-15 12:41 ` Sebastian Siewior
2023-05-16 9:24 ` Frederic Weisbecker
2023-05-16 9:37 ` Sebastian Siewior [this message]
2023-05-16 12:49 ` Anna-Maria Behnsen
2023-05-16 9:15 ` Frederic Weisbecker
2023-05-11 16:56 ` Sebastian Siewior
2023-05-15 11:06 ` Sebastian Siewior
2023-05-19 9:32 ` kernel test robot
2023-05-10 7:28 ` [PATCH v6 20/21] timer_migration: Add tracepoints Anna-Maria Behnsen
2023-05-10 7:28 ` [PATCH v6 21/21] timer: Always queue timers on the local CPU Anna-Maria Behnsen
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