From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AA8BE48EC69; Mon, 21 Sep 2026 12:57:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789995467; cv=none; b=pBWyVWeU4b1SNVLveeLDPpMb02xzMpPPpNF84QWmljUQ6eAzvTW0CgowuxOyMDAYTpaKVhbnpsvcid4wXsyfKweBiZuST4ialV7sIPIIS1MOaoeiEOy9yECcNxtKNd5gOy9SsXDHYzHx4gDAkWr6FinE15bz24BdIE+yR1isgQw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789995467; c=relaxed/simple; bh=XYTz/bDPy5AHdbPxHZeZXwjBR/dn5+7P39D2RiVuLCw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MLI0C+303wTcIab2dsQdxpcewa90YE7nmvY0kvFLEWcC8XSxTdNY/2peFTemEfl1g4RU/90N7wmVHu2qX+5eDeRrOi7XsbB32L3OlChFmgSj6X0+lMgAos1NvbuxlNkW7Q15MzJ8JoBZYEUBl5cfl+q83D5FUFmU2NSMkHIv01A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=iSLQ+a/0; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=b6QDQCYS; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="iSLQ+a/0"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="b6QDQCYS" Date: Mon, 21 Sep 2026 14:57:40 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1789995462; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+AJpnD11/J/hkZ8Y91nI/UwOF80ppZScsajgHoSnUk8=; b=iSLQ+a/0vNHSUlFe7NBhiSRN8xRU3xjIIq44BDEjhCAbVYSyM2nP3lqRwZ5nY93K8tIKuS PYn6n1os6iXs+j6yhVA9rHmUljX+I5DAkCf0nhCFztOhjqCqzT6zj3NoQ35d/7GQkJbGg7 6Ns7wG6KBjAYSO5gKYxf2Exdg1uyNaYhi+G5pl2zCmg+92ebXltc2cDgMn8GDYNYH8Lm/1 2/9AWs0JbPCQML71aFfotH0fazGun4Gq3+4aRoOuINGVZrwrsN4Nei4rtVmDDl8QGLpF4T BXs6lYP+H+plE0qWDAc0ejuTea2hrJbUtg8ya6DF7EAlzB6nKQ+Yhb6nlRjTXQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1789995462; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+AJpnD11/J/hkZ8Y91nI/UwOF80ppZScsajgHoSnUk8=; b=b6QDQCYSvLu83vFCbBLNglQBwD1zRQ/8iVGWsPCHPhEVCIZFkNOHpLRw6nXQky3qmqFCi6 iU7906F8jHFdlSDA== From: Sebastian Andrzej Siewior To: Quchaosheng Cc: Ingo Molnar , Peter Zijlstra , John Stultz , Valentin Schneider , Waiman Long , Boqun Feng , Will Deacon , Thomas Gleixner , Juri Lelli , Vincent Guittot , K Prateek Nayak , linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org Subject: Re: [PATCH] sched/proxy: allow SCHED_PROXY_EXEC with PREEMPT_RT Message-ID: <20260921125740.vKjQ0Qtr@linutronix.de> References: <20260921081525.2982361-1-quchaosheng000406@163.com> <20260921100921.PsZhWgmh@linutronix.de> <178998790498.3308959.13462163523351109568@163.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <178998790498.3308959.13462163523351109568@163.com> On 2026-09-21 18:51:44 [+0800], Quchaosheng wrote: > On 2026-09-21 12:09:21 [+0200], Sebastian Andrzej Siewior wrote: > > Why exactly is this a good thing to do? > > What the patch does is make a combination that the Kconfig itself already > documents as broken ("Avoid some build failures w/ PREEMPT_RT until it can > be fixed") compile again, and drop the RT stub in include/linux/sched.h > whose parameter type did not match any caller. That is the whole of it. Is there a build failure as of today or not? The whole proxy exec thingy depends on !PREEMPT_RT, so there should be no build failures. > If that is not worth carrying, I would rather withdraw the patch than > argue for it. Enabling a config that silently does nothing is a fair > objection, and teaching the RT mutex to maintain blocked_on is the real > work here. I still fail to understand why we want it. It does nothing. The option itself is document and once enabled CONFIG_SCHED_PROXY_EXEC does something an !PREEMPT_RT and leads to a different behaviour if disabled. But with your patch and PREEMPT_RT enabled there would be nothing that CONFIG_SCHED_PROXY_EXEC does, would there be? Sebastian