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?
next prev parent reply other threads:[~2021-10-18 10:53 UTC|newest]
Thread overview: 7+ 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
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