From: Thomas Gleixner <tglx@linutronix.de>
To: Bitao Hu <yaoma@linux.alibaba.com>,
dianders@chromium.org, akpm@linux-foundation.org,
liusong@linux.alibaba.com, pmladek@suse.com,
kernelfans@gmail.com, deller@gmx.de, npiggin@gmail.com,
tsbogend@alpha.franken.de, James.Bottomley@HansenPartnership.com,
jan.kiszka@siemens.com
Cc: linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org,
linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
yaoma@linux.alibaba.com
Subject: Re: [PATCHv9 2/3] irq: use a struct for the kstat_irqs in the interrupt descriptor
Date: Fri, 23 Feb 2024 08:29:36 +0100 [thread overview]
Message-ID: <87frxjeizj.ffs@tglx> (raw)
In-Reply-To: <3f4b7dbe-93c1-4cb0-8233-18e8432409f8@linux.alibaba.com>
On Fri, Feb 23 2024 at 15:18, Bitao Hu wrote:
> On 2024/2/22 21:22, Thomas Gleixner wrote:
>>> - if (desc->kstat_irqs) {
>>> - for_each_online_cpu(j)
>>> - any_count |= data_race(*per_cpu_ptr(desc->kstat_irqs, j));
>>> - }
>>> + if (desc->kstat_irqs)
>>> + any_count = data_race(desc->tot_count);
>>
>> This is an unrelated change and needs to be split out into a separate
>> patch with a proper changelog which explains why this is equivalent.
>>
>
> Alright, I will remove this change witch is not related to the purpose
> of this patch.
>
> I guess that the purpose of suggesting this change in your V1 response
> was to speedup the 'show_interrupts'. However, after reviewing the
> usage of 'desc->tot_count' in 'unsigned int kstat_irqs(unsigned int
> irq)', I think the change might be as follows:
>
> diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
> index 623b8136e9af..53b8d6edd7ac 100644
> --- a/kernel/irq/proc.c
> +++ b/kernel/irq/proc.c
> @@ -489,8 +489,13 @@ int show_interrupts(struct seq_file *p, void *v)
> goto outsparse;
>
> if (desc->kstat_irqs) {
> - for_each_online_cpu(j)
> - any_count |=
> data_race(per_cpu(desc->kstat_irqs->cnt, j));
> + if (!irq_settings_is_per_cpu_devid(desc) &&
> + !irq_settings_is_per_cpu(desc) &&
> + !irq_is_nmi(desc))
> + any_count = data_race(desc->tot_count);
> + else
> + for_each_online_cpu(j)
> + any_count |=
> data_race(per_cpu(desc->kstat_irqs->cnt, j));
> }
>
> if ((!desc->action || irq_desc_is_chained(desc)) && !any_count)
>
> Is my idea correct?
Yes.
next prev parent reply other threads:[~2024-02-23 7:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-22 9:34 [PATCHv9 0/3] *** Detect interrupt storm in softlockup *** Bitao Hu
2024-02-22 9:34 ` [PATCHv9 1/3] watchdog/softlockup: low-overhead detection of interrupt storm Bitao Hu
2024-02-22 9:34 ` [PATCHv9 2/3] irq: use a struct for the kstat_irqs in the interrupt descriptor Bitao Hu
2024-02-22 13:22 ` Thomas Gleixner
2024-02-23 7:18 ` Bitao Hu
2024-02-23 7:29 ` Thomas Gleixner [this message]
2024-02-22 9:34 ` [PATCHv9 3/3] watchdog/softlockup: report the most frequent interrupts Bitao Hu
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