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From: Peter Zijlstra <peterz@infradead.org>
To: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	mingo@kernel.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	vschneid@redhat.com, jpoimboe@kernel.org, jikos@kernel.org,
	joe.lawrence@redhat.com, linux-kernel@vger.kernel.org,
	live-patching@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [RFC][PATCH] sched,livepatch: Untangle cond_resched() and live-patching
Date: Wed, 26 Mar 2025 15:42:12 +0100	[thread overview]
Message-ID: <20250326144212.GG25239@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.LSU.2.21.2503261534450.4152@pobox.suse.cz>

On Wed, Mar 26, 2025 at 03:37:50PM +0100, Miroslav Benes wrote:

> If I remember correctly, we had something like this in the old kGraft 
> implementation of the live patching (SUSE way). We exactly had a hook 
> somewhere in the kthread freezing code. This looks much cleaner and as far 
> as I know the fridge went through improvements recently.

Yeah, I rewrote it a while ago :-)

> Peter, so that I understand it correctly... we would rely on all kthreads 
> becoming freezable eventually so that both suspend and livepatch benefit. 
> Is that what you meant by the above?

Well, IIRC (its been a while already) all kthreads should have a
FREEZABLE already. Things like suspend-to-idle don't hit the hotplug
path at all anymore and everything must freeze, otherwise they fail.

I was more meaning the time-to-freeze; if some kthreads take a long time
to freeze/patch then this would want improving on both ends.

  reply	other threads:[~2025-03-26 14:42 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-24 13:49 [RFC][PATCH] sched,livepatch: Untangle cond_resched() and live-patching Peter Zijlstra
2025-03-26  9:49 ` Petr Mladek
2025-03-26 10:38   ` Peter Zijlstra
2025-03-26 14:37     ` Miroslav Benes
2025-03-26 14:42       ` Peter Zijlstra [this message]
2025-03-26 14:52         ` Miroslav Benes
2025-03-26 14:54 ` Miroslav Benes

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