linux-kernel - Re: [PATCH v2 05/10] um: Determine sleep based on need

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Message-ID: <55cace5b8e1078bd04b4a1acb5df9faa6a83b6e8.camel@sipsolutions.net>
Date: Wed, 10 Sep 2025 14:10:37 +0200
From: Johannes Berg <johannes@...solutions.net>
To: Tiwei Bie <tiwei.bie@...ux.dev>, richard@....at, 
	anton.ivanov@...bridgegreys.com
Cc: linux-um@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	benjamin@...solutions.net, arnd@...db.de, tiwei.btw@...group.com
Subject: Re: [PATCH v2 05/10] um: Determine sleep based on need_resched()

On Sun, 2025-08-10 at 13:51 +0800, Tiwei Bie wrote:
> From: Tiwei Bie <tiwei.btw@...group.com>
> 
> With SMP and NO_HZ enabled, the CPU may still need to sleep even
> if the timer is disarmed. Switch to deciding whether to sleep based
> on pending resched. This is a preparation for adding SMP support.

What's the rationale for need_resched()? Is that somehow defined for
this? Is it what other architectures use? I guess I'm just not entirely
sure what it means.

johannes