From: pintu.ping@gmail.com (Pintu Agarwal)
To: kernelnewbies@lists.kernelnewbies.org
Subject: [ARM64] Printing IRQ stack usage information
Date: Tue, 20 Nov 2018 18:21:33 +0530 [thread overview]
Message-ID: <CAOuPNLgGuomqaQVtj=1O8tYV_Bq8cqf5HqCxJ-LSGeQOVffnzw@mail.gmail.com> (raw)
In-Reply-To: <CAOuPNLiJmtXft6g63oATMrrrcd3jQGCfxsAzXLx8Kz=_zsR4Kg@mail.gmail.com>
On Sat, Nov 17, 2018 at 6:36 PM Pintu Agarwal <pintu.ping@gmail.com> wrote:
>
> On Sat, Nov 17, 2018 at 12:02 AM <valdis.kletnieks@vt.edu> wrote:
> >
> > > 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 ?
> >
> > Make the high-water mark a per-cpu variable.
> >
> > > 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 ?
> >
> > No, you don't do a dump-stack during entry/exit. You just maintain a high-water
> > value in the exit,
>
> Which is the right place to keep track of this
> high-water-irq-stack-usage (per_cpu)
> in arch/arm64/* ?
>
I tried to create a per-cpu irq_stack_usage variable like this in :
arch/arm64/include/asm/hardirq.h
+DECLARE_PER_CPU(unsigned int, irq_stack_usage);
But, I could not figure out, from where to fill these variable for irq
stack usage.
+ sp = current_stack_pointer;
+ if (on_irq_stack(sp, cpu)) {
+ stack_start = (unsigned long)per_cpu(irq_stack, cpu);
+ last_usage = per_cpu(irq_stack_usage, cpu);
+ curr_usage = sp - stack_start;
+ pr_info("cpu:%d : sp: %lu, stack_start: %lu, usage: %lu\n",
cpu, sp, stack_start, (sp - stack_start));
+ if (curr_usage > last_usage)
+ per_cpu(irq_stack_usage, cpu) = curr_usage;
+ }
Which is the best place to invoke this ?
I have the following option:
1. kernel/softirq.c => __do_softirq()
2. arch/arm64/kernel/smp.c => handle_IPI()
3. kernel/softirq.c => irq_exit()
4. ???
Please let me know.
Thank You!
Pintu
WARNING: multiple messages have this Message-ID (diff)
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: Tue, 20 Nov 2018 18:21:33 +0530 [thread overview]
Message-ID: <CAOuPNLgGuomqaQVtj=1O8tYV_Bq8cqf5HqCxJ-LSGeQOVffnzw@mail.gmail.com> (raw)
Message-ID: <20181120125133.BFqiwMbVgiM6NS4zhOYnF_1JlNUFjpGlxzga-lJJoHc@z> (raw)
In-Reply-To: <CAOuPNLiJmtXft6g63oATMrrrcd3jQGCfxsAzXLx8Kz=_zsR4Kg@mail.gmail.com>
On Sat, Nov 17, 2018 at 6:36 PM Pintu Agarwal <pintu.ping@gmail.com> wrote:
>
> On Sat, Nov 17, 2018 at 12:02 AM <valdis.kletnieks@vt.edu> wrote:
> >
> > > 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 ?
> >
> > Make the high-water mark a per-cpu variable.
> >
> > > 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 ?
> >
> > No, you don't do a dump-stack during entry/exit. You just maintain a high-water
> > value in the exit,
>
> Which is the right place to keep track of this
> high-water-irq-stack-usage (per_cpu)
> in arch/arm64/* ?
>
I tried to create a per-cpu irq_stack_usage variable like this in :
arch/arm64/include/asm/hardirq.h
+DECLARE_PER_CPU(unsigned int, irq_stack_usage);
But, I could not figure out, from where to fill these variable for irq
stack usage.
+ sp = current_stack_pointer;
+ if (on_irq_stack(sp, cpu)) {
+ stack_start = (unsigned long)per_cpu(irq_stack, cpu);
+ last_usage = per_cpu(irq_stack_usage, cpu);
+ curr_usage = sp - stack_start;
+ pr_info("cpu:%d : sp: %lu, stack_start: %lu, usage: %lu\n",
cpu, sp, stack_start, (sp - stack_start));
+ if (curr_usage > last_usage)
+ per_cpu(irq_stack_usage, cpu) = curr_usage;
+ }
Which is the best place to invoke this ?
I have the following option:
1. kernel/softirq.c => __do_softirq()
2. arch/arm64/kernel/smp.c => handle_IPI()
3. kernel/softirq.c => irq_exit()
4. ???
Please let me know.
Thank You!
Pintu
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next prev parent reply other threads:[~2018-11-20 12:51 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-15 13:22 [ARM64] Printing IRQ stack usage information Pintu Agarwal
2018-11-15 13:22 ` Pintu Agarwal
2018-11-15 16:49 ` valdis.kletnieks at vt.edu
2018-11-15 16:49 ` valdis.kletnieks
2018-11-16 6:14 ` Pintu Agarwal
2018-11-16 6:14 ` Pintu Agarwal
2018-11-16 11:33 ` valdis.kletnieks at vt.edu
2018-11-16 11:33 ` valdis.kletnieks
2018-11-16 14:40 ` Pintu Agarwal
2018-11-16 14:40 ` Pintu Agarwal
2018-11-16 16:46 ` valdis.kletnieks at vt.edu
2018-11-16 16:46 ` valdis.kletnieks
2018-11-16 17:43 ` Pintu Agarwal
2018-11-16 17:43 ` Pintu Agarwal
2018-11-16 18:31 ` valdis.kletnieks at vt.edu
2018-11-16 18:31 ` valdis.kletnieks
2018-11-17 13:06 ` Pintu Agarwal
2018-11-17 13:06 ` Pintu Agarwal
2018-11-20 12:51 ` Pintu Agarwal [this message]
2018-11-20 12:51 ` Pintu Agarwal
2018-11-20 19:03 ` valdis.kletnieks at vt.edu
2018-11-20 19:03 ` valdis.kletnieks
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