linux-kernel - Re: [PATCH] irq_work: Avoid unnecessary "IRQ work" interrupts

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Message-ID: <20240828140223.P5vGN54Q@linutronix.de>
Date: Wed, 28 Aug 2024 16:02:23 +0200
From: "bigeasy@...utronix.de" <bigeasy@...utronix.de>
To: "Brandt, Oliver - Lenze" <oliver.brandt@...ze.com>
Cc: "tglx@...utronix.de" <tglx@...utronix.de>,
	"peterz@...radead.org" <peterz@...radead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] irq_work: Avoid unnecessary "IRQ work" interrupts

On 2024-08-28 13:26:42 [+0000], Brandt, Oliver - Lenze wrote:
> 
> Hmm.... I see. What about calling wake_irq_workd() directly; something
> like
> 
>         if (rt_lazy_work)
>                 wake_irq_workd();
>         else if (!lazy_work || tick_nohz_tick_stopped())
>                 irq_work_raise(work);

this might work but I'm not too sure about it. This will become a
problem if irq_work_queue() is invoked from a path where scheduling is
not possible due to recursion or acquired locks. 

How much of a problem is it and how much you gain by doing so?

> Regards,
> Oliver

Sebastian