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Groups > linux.kernel > #1443802
| From | Viresh Kumar <viresh.kumar@linaro.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [Query] Preemption (hogging) of the work handler |
| Date | 2016-07-15 00:00 +0200 |
| Message-ID | <rUWPM-6EB-7@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <rTS1P-4LO-17@gated-at.bofh.it> <rUfhL-3hH-9@gated-at.bofh.it> <rUldv-7d1-13@gated-at.bofh.it> <rUuA9-4Zu-5@gated-at.bofh.it> <rUDap-2gp-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 14-07-16, 09:55, Sergey Senozhatsky wrote:
> excessive printing is just part of the problem here. if we cab cond_resched()
> part of suspend/hibernation is cpu_down(), which lands in console_cpu_notify(),
> that does synchronous printing for every CPU taken down:
>
> static int console_cpu_notify(struct notifier_block *self,
> unsigned long action, void *hcpu)
> {
> switch (action) {
> case CPU_ONLINE:
> case CPU_DEAD:
> case CPU_DOWN_FAILED:
> case CPU_UP_CANCELED:
> console_lock();
> console_unlock();
> ^^^^^^^^^^^^^^
> }
> return NOTIFY_OK;
> }
>
> console_unlock() is synchronous (I posted a very early draft patch that makes
> it asynchronous, but that's a future work). so if there is a ton of printk()-s,
> then console_unlock() will print it, 100% guaranteed. even if printk_kthread
> is doing the printing job at the moment, cpu down path will wait for it to
> stop, lock the console semaphore, and got to console_unlock() printing loop.
Hmm...
> in printk that you have posted, that will happen not only for CPU_DEAD,
It doesn't happen for CPU_DEAD right now as CONFIG_CONSOLE_FLUSH_ON_HOTPLUG
isn't enabled in my setup.
> but for CPU_DYING as well (possibly, there is a /* invoked with preemption
> disabled, so defer */ comment, so may be you never endup doing direct
> printk there, but then you schedule a console_unlock() work).
--
viresh
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Re: [Query] Preemption (hogging) of the work handler Jan Kara <jack@suse.cz> - 2016-07-11 12:30 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-07-11 17:50 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-07-12 00:40 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 00:50 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-07-12 14:30 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 15:10 +0200
Re: [Query] Preemption (hogging) of the work handler Petr Mladek <pmladek@suse.com> - 2016-07-12 16:00 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 16:10 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 00:40 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-07-12 11:40 +0200
Re: [Query] Preemption (hogging) of the work handler Petr Mladek <pmladek@suse.com> - 2016-07-12 15:00 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 15:20 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 19:20 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-12 22:10 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rafael@kernel.org> - 2016-07-12 22:10 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-07-13 09:10 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rafael@kernel.org> - 2016-07-13 14:10 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-07-13 15:00 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rafael@kernel.org> - 2016-07-13 15:30 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-07-12 16:10 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-15 02:00 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-07-15 15:20 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-15 18:00 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-13 01:30 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-13 02:20 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-07-13 07:50 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-13 17:50 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rafael@kernel.org> - 2016-07-14 01:10 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-14 01:20 +0200
Re: [Query] Preemption (hogging) of the work handler Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-07-14 01:40 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-07-14 03:00 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rafael@kernel.org> - 2016-07-14 03:10 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-07-14 03:40 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-15 00:00 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-15 00:00 +0200
Re: [Query] Preemption (hogging) of the work handler Jan Kara <jack@suse.cz> - 2016-07-14 16:20 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-07-14 16:30 +0200
Re: [Query] Preemption (hogging) of the work handler Jan Kara <jack@suse.cz> - 2016-07-14 16:40 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-07-14 16:50 +0200
Re: [Query] Preemption (hogging) of the work handler Jan Kara <jack@suse.cz> - 2016-07-14 17:00 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-15 00:20 +0200
Re: [Query] Preemption (hogging) of the work handler Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-07-14 16:40 +0200
Re: [Query] Preemption (hogging) of the work handler Jan Kara <jack@suse.cz> - 2016-07-14 17:10 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-15 00:20 +0200
Re: [Query] Preemption (hogging) of the work handler Jan Kara <jack@suse.cz> - 2016-07-18 13:10 +0200
Re: [Query] Preemption (hogging) of the work handler "Rafael J. Wysocki" <rjw@rjwysocki.net> - 2016-07-18 13:50 +0200
Re: [Query] Preemption (hogging) of the work handler Viresh Kumar <viresh.kumar@linaro.org> - 2016-07-11 21:10 +0200
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