Re: [ARM64] Printing IRQ stack usage information

From: Pintu Agarwal <pintu.ping@gmail.com>
To: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: mark.rutland@arm.com, Jungseok Lee <jungseoklee85@gmail.com>,
	kernelnewbies@kernelnewbies.org, catalin.marinas@arm.com,
	Sungjinn Chung <barami97@gmail.com>,
	will.deacon@arm.com, open list <linux-kernel@vger.kernel.org>,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	Takahiro Akashi <takahiro.akashi@linaro.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [ARM64] Printing IRQ stack usage information
Date: Fri, 16 Nov 2018 23:13:48 +0530	[thread overview]
Message-ID: <CAOuPNLiX0zhxiRAx03YjVU6cocwWbgY9naxeYPRKmT+3PoGhRw@mail.gmail.com> (raw)
Message-ID: <20181116174348.l5gnkrQDXreov1Rn1kxkJtTFY6JMm8tzUaNb_afT3DU@z> (raw)
In-Reply-To: <5997.1542386778@turing-police.cc.vt.edu>

On Fri, Nov 16, 2018 at 10:16 PM <valdis.kletnieks@vt.edu> wrote:
>
> On Fri, 16 Nov 2018 20:10:28 +0530, Pintu Agarwal said:
>
> > > Look at the code controlled by '#ifdef CONFIG_DEBUG_STACK_USAGE'
>
> > For example: is it possible to keep storing the irq_stack_usage (for
> > each cpu in a variable) information from boot time, and then use this
> > variable to dump the irq_stack information, after the system booted,
> > may be from proc entry ?
>
> Congrats. You just re-invented DEBUG_STACK_USAGE, which just keeps a high-water mark
> for stack usage.

So, you mean to say, my implementation is good enough to get the
irq_stack usage, from the interrupt handler ?
But my concern is that if I dump it from irq handler, I will get
information only for the current cpu.
How do I store and get the information for all the cpu from the boot time ?
>From where do I call my dump_irq_stack_info() [some where during the
entry/exit part of the irq handler], so that I could dump information
for all the handler at boot time itself ?
Like I would to capture these information:
- What was the name of the handler ?
- Which cpu was executing it ?
- How much irq stack (max value, same like high water mark) were used
at that time ?

Where can I collect these information from the boot time ?

Thanks,
Pintu

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