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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Valentin Schneider <valentin.schneider@arm.com>,
	linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>
Subject: Re: [SPLAT 1/3] arm_pmu: Sleeping spinlocks down armpmu_alloc_atomic()
Date: Tue, 10 Aug 2021 20:39:14 +0200	[thread overview]
Message-ID: <20210810183914.2wd7hehdz7y4crla@linutronix.de> (raw)
In-Reply-To: <874kbxqkyk.ffs@tglx>

On 2021-08-10 19:16:19 [+0200], Thomas Gleixner wrote:
> On Tue, Aug 10 2021 at 15:54, Sebastian Andrzej Siewior wrote:
> > On 2021-08-10 14:41:25 [+0100], Valentin Schneider wrote:
> >> [    4.172817] BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:35
> >
> > Would it work to allocate the memory upfront and invoke the HP callback
> > via smp_function_call()?
> 
> Huch? If the memory is allocated during the prepare stage then the
> actual hotplug callback can just use it. So what's the SMP function call
> for?

You allocate the memory per-node (based on cpuid id) and you figure that
out on the target CPU. That is the smp-function call for unless there
another way to gather that information.
That is done in
 arm_pmu_acpi_find_alloc_pmu() -> read_cpuid_id()

> Thanks,
> 
>         tglx

Sebastian

  reply	other threads:[~2021-08-10 18:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-10 13:41 [SPLAT 0/3] Sleeping spinlocks in troublesome contexts on v5.14-rc4-rt6 Valentin Schneider
2021-08-10 13:41 ` [SPLAT 1/3] arm_pmu: Sleeping spinlocks down armpmu_alloc_atomic() Valentin Schneider
2021-08-10 13:54   ` Sebastian Andrzej Siewior
2021-08-10 17:16     ` Thomas Gleixner
2021-08-10 18:39       ` Sebastian Andrzej Siewior [this message]
2021-08-10 19:56         ` Thomas Gleixner
2021-08-10 13:41 ` [SPLAT 2/3] irqchip/gic-v3-its: Sleeping spinlocks down gic_reserve_range() Valentin Schneider
2021-08-11  8:50   ` Marc Zyngier
2021-08-11 12:28     ` Thomas Gleixner
2021-08-11 15:14       ` Marc Zyngier
2021-08-17 15:16     ` Ard Biesheuvel
2021-08-10 13:41 ` [SPLAT 3/3] gpio: dwapb: Sleeping spinlocks down IRQ mapping Valentin Schneider
2021-08-10 20:33   ` Thomas Gleixner
2021-08-11 10:52   ` Andy Shevchenko

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