From: Thomas Gleixner <tglx@linutronix.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [patch V2 17/17] sched: Enable might_sleep() and smp_processor_id() checks early
Date: Wed, 17 May 2017 00:46:37 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1705170040440.2095@nanos> (raw)
In-Reply-To: <20170516151236.3ca5d9ae@gandalf.local.home>
On Tue, 16 May 2017, Steven Rostedt wrote:
> On Tue, 16 May 2017 20:42:48 +0200
> Thomas Gleixner <tglx@linutronix.de> wrote:
> > +
> > + /*
> > + * Enable might_sleep() and smp_processor_id() checks.
> > + * They cannot be enabled earlier because with CONFIG_PRREMPT=y
>
> My cat's version of CONFIG_PREEMPT, it's CONFIG_ PRR EMPT!
I don't have a cat and I don't need one for creating typos. I'm perfectly
able to do that myself :)
> > + * kernel_thread() would trigger might_sleep() splats. With
> > + * CONFIG_PREEMPT_VOLUNTARY=y the init task might have scheduled
> > + * already, but it's stuck on the kthreadd_done completion.
> > + */
> > + system_state = SYSTEM_SCHEDULING;
> > +
> > complete(&kthreadd_done);
> >
> > /*
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -6226,8 +6226,10 @@ void ___might_sleep(const char *file, in
> >
> > if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
> > !is_idle_task(current)) ||
> > - system_state != SYSTEM_RUNNING || oops_in_progress)
> > + system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
> > + oops_in_progress)
> > return;
> > +
> > if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
> > return;
> > prev_jiffy = jiffies;
> > --- a/lib/smp_processor_id.c
> > +++ b/lib/smp_processor_id.c
> > @@ -28,7 +28,7 @@ notrace static unsigned int check_preemp
> > /*
> > * It is valid to assume CPU-locality during early bootup:
> > */
> > - if (system_state != SYSTEM_RUNNING)
> > + if (system_state < SYSTEM_SCHEDULING)
>
> Do we want to ignore halting or rebooting too?
I don't think so. After setting those states, interesting stuff like
device_shutdown() gets invoked. We want the coverage there.
Thanks,
tglx
next prev parent reply other threads:[~2017-05-16 22:46 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-16 18:42 [patch V2 00/17] init: Enable might_sleep() and smp_processor_id() debugging early Thomas Gleixner
2017-05-16 18:42 ` [patch V2 01/17] init: Pin init task to boot cpu initially Thomas Gleixner
2017-05-16 19:06 ` Steven Rostedt
2017-05-23 8:47 ` [tip:sched/core] init: Pin init task to the boot CPU, initially tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 02/17] arm: Adjust system_state check Thomas Gleixner
2017-05-23 8:48 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 03/17] arm64: " Thomas Gleixner
2017-05-17 10:09 ` Mark Rutland
2017-05-17 14:23 ` Catalin Marinas
2017-05-23 8:48 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 04/17] x86/smp: " Thomas Gleixner
2017-05-23 8:49 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 05/17] metag: " Thomas Gleixner
2017-05-23 8:50 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 06/17] powerpc: " Thomas Gleixner
2017-05-23 8:50 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 07/17] ACPI: " Thomas Gleixner
2017-05-16 19:07 ` Steven Rostedt
2017-05-23 8:51 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 08/17] mm: " Thomas Gleixner
2017-05-23 8:51 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 09/17] cpufreq/pasemi: " Thomas Gleixner
2017-05-23 8:52 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 10/17] iommu/vt-d: Adjust system_state checks Thomas Gleixner
2017-05-23 8:52 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 11/17] iommu/of: Adjust system_state check Thomas Gleixner
2017-05-23 8:53 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 12/17] async: Adjust system_state checks Thomas Gleixner
2017-05-23 8:53 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 13/17] extable: " Thomas Gleixner
2017-05-23 8:54 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 14/17] printk: " Thomas Gleixner
2017-05-23 8:55 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 15/17] mm/vmscan: " Thomas Gleixner
2017-05-17 6:56 ` Vlastimil Babka
2017-05-23 8:55 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 16/17] init: Introduce SYSTEM_SCHEDULING state Thomas Gleixner
2017-05-17 10:58 ` Mark Rutland
2017-05-17 21:15 ` Boris Ostrovsky
2017-05-23 8:56 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2017-05-16 18:42 ` [patch V2 17/17] sched: Enable might_sleep() and smp_processor_id() checks early Thomas Gleixner
2017-05-16 19:12 ` Steven Rostedt
2017-05-16 22:46 ` Thomas Gleixner [this message]
2017-05-16 22:50 ` Steven Rostedt
2017-05-17 11:02 ` Mark Rutland
2017-05-23 8:56 ` [tip:sched/core] sched/core: " tip-bot for Thomas Gleixner
2017-05-17 10:58 ` [patch V2 00/17] init: Enable might_sleep() and smp_processor_id() debugging early Mark Rutland
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