All of lore.kernel.org
 help / color / mirror / Atom feed
From: Christoph Hellwig <hch@infradead.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Christoph Hellwig <hch@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] irq_poll: Use raise_softirq_irqoff() in cpu_dead notifier
Date: Mon, 18 Oct 2021 03:53:20 -0700	[thread overview]
Message-ID: <YW1SIE08f3X3joxe@infradead.org> (raw)
In-Reply-To: <20210930103754.2128949-1-bigeasy@linutronix.de>

On Thu, Sep 30, 2021 at 12:37:54PM +0200, Sebastian Andrzej Siewior wrote:
> __raise_softirq_irqoff() adds a bit to the pending sofirq mask and this
> is it. The softirq won't be handled in a deterministic way but randomly
> when an interrupt fires and handles softirq in its irq_exit() routine or
> if something randomly checks and handles pending softirqs in the call
> chain before the CPU goes idle.
> 
> Add a local_bh_disable/enable() around the IRQ-off section which will
> handle pending softirqs.

This patch leaves me extremely confused, and it would even more if I was
just reading the code.  local_irq_disable is supposed to disable BHs
as well, so the code looks pretty much nonsensical to me.  But
apparently that isn't the point if I follow your commit message as you
don't care about an extra level of BH disabling but want to force a
side-effect of the re-enabling?  Why not directly call the helper
to schedule the softirq then? 

  parent reply	other threads:[~2021-10-18 10:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-30 10:37 [PATCH] irq_poll: Use raise_softirq_irqoff() in cpu_dead notifier Sebastian Andrzej Siewior
2021-09-30 10:56 ` [RFC] Is lib/irq_poll still considered useful? Sebastian Andrzej Siewior
2021-10-01  4:24   ` Christoph Hellwig
2021-10-01  6:41     ` Sebastian Andrzej Siewior
2021-10-18  7:45 ` [PATCH] irq_poll: Use raise_softirq_irqoff() in cpu_dead notifier Sebastian Andrzej Siewior
2021-10-18 10:53 ` Christoph Hellwig [this message]
2021-10-18 11:49   ` Sebastian Andrzej Siewior
  -- strict thread matches above, loose matches on Subject: below --
2020-04-02 19:50 Sebastian Andrzej Siewior

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=YW1SIE08f3X3joxe@infradead.org \
    --to=hch@infradead.org \
    --cc=bigeasy@linutronix.de \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-scsi@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.