From: Frederic Weisbecker <frederic@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
rafael@kernel.org, daniel.lezcano@linaro.org,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
len.brown@intel.com
Subject: Re: [RFC/RFT PATCH 1/2] sched/core: Check and schedule ksoftirq
Date: Fri, 16 Dec 2022 23:07:48 +0100 [thread overview]
Message-ID: <20221216220748.GA1967978@lothringen> (raw)
In-Reply-To: <Y5xURk3CkzhIjmmq@hirez.programming.kicks-ass.net>
On Fri, Dec 16, 2022 at 12:19:34PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 15, 2022 at 10:42:59AM -0800, Srinivas Pandruvada wrote:
> > + /* Give ksoftirqd 1 jiffy to get a chance to start its job */
> > + if (!READ_ONCE(it.done) && task_is_running(__this_cpu_read(ksoftirqd))) {
> > + __set_current_state(TASK_UNINTERRUPTIBLE);
> > + schedule_timeout(1);
> > + }
>
> That's absolutely disgusting :-/
I know, and I hate checking task_is_running(__this_cpu_read(ksoftirqd))
everywhere in idle. And in fact it doesn't work because some cpuidle drivers
also do need_resched() checks.
I guess that either we assume that the idle injection is more important
than serving softirqs and we shutdown the warnings accordingly, or we arrange
for idle injection to have a lower prio than ksoftirqd.
Thoughts?
next prev parent reply other threads:[~2022-12-16 22:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-15 18:42 [RFC/RFT PATCH 0/2] Forced idle and Non-RCU local softirq pending Srinivas Pandruvada
2022-12-15 18:42 ` [RFC/RFT PATCH 1/2] sched/core: Check and schedule ksoftirq Srinivas Pandruvada
2022-12-16 11:19 ` Peter Zijlstra
2022-12-16 16:58 ` srinivas pandruvada
2022-12-16 22:07 ` Frederic Weisbecker [this message]
2022-12-19 11:33 ` Peter Zijlstra
2022-12-19 11:46 ` Sebastian Andrzej Siewior
2022-12-19 14:56 ` Peter Zijlstra
2022-12-19 22:54 ` srinivas pandruvada
2022-12-20 20:51 ` Peter Zijlstra
2022-12-20 21:18 ` Peter Zijlstra
2023-01-10 2:33 ` srinivas pandruvada
2022-12-15 18:43 ` [RFC/RFT PATCH 2/2] sched/core: Add max duration to play_precise_idle() Srinivas Pandruvada
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