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 D9E331BFE0B for ; Thu, 10 Oct 2024 10:27:01 +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=1728556023; cv=none; b=WT28z/80HkLGZBW+kCEmwBeQZlmSgiavnCVQedwd+J7TmkgomKg9PcSKCKUfXCdhtQrybQLkl23bRDBMGEXHJ62H4u6WnJvAc3+TTNehVJCfpdz5Y9rxxRD5Fhc189PCY6neGfFD+eUIOFy3322REQ2z9fUHqxT84J3/vvcwPHw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728556023; c=relaxed/simple; bh=Zcwqr+AwcUDSNxX0xkLd+10HDTyg1jPzohbE6jwSFwM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pTZIRtnAbAgjvrWzCEps0Spk8L+P5Fjb7FfYxIRR0ijit4LwWo5ECLm6uVzHBDxWAMFQU3lwaU8+/u+Xw4SsK5u9XS+VDx650jmAVw4T+7EAvEweJxrYRoqwdThw+xsD+9KCzXbN4aWE+x1lryObqq80OfTxOcpi3MIMZGL1pmI= 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=yZJ9IR67; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=C+ZK8Irb; 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="yZJ9IR67"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="C+ZK8Irb" Date: Thu, 10 Oct 2024 12:26:57 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1728556019; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tnezkotHKXVjhl9YICjV8wtVMuR62azVKg2NoQ6mASU=; b=yZJ9IR67ywRbn0fjvy3qXDFY566Ze0RQ3aKxzTMKVKxQQxBS03qNHuxIY5OR3h7+qPBbn6 lC78IgtMhQ84xcy5A99M3iTGhDaiZlWLlNvZB789q5DkXtjHlVQqkk+Q68sFZ66PC6Oc4R X3tM8pHDEZyc/XMmQ50MiDGGLOmZdAqOqLDekJ8aEjhziy4WRM7dUneMQSVmDnCsF5AHvE l8AUA3Yi6wGXHsYuaRhCpq4hnYyDXZFuKLALCjjJZH2RPhoKgNJDZKDVZElga2Oh1hfSrj NBWoR+3NZinOHksdCm3IFzhVW0JfcoufD4lgGMkvWUpOxb6R0q0fQEq+u9sfNw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1728556019; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=tnezkotHKXVjhl9YICjV8wtVMuR62azVKg2NoQ6mASU=; b=C+ZK8Irb7v6/Rv1Souxa3qMghds6shfwpCCjXXhC9qPmqBCymgDAH9M2vhQ/CXIro3Hr0X WfGJg+vl6DnHPtCg== From: Sebastian Andrzej Siewior To: Peter Zijlstra Cc: "Paul E. McKenney" , Ankur Arora , linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, frederic@kernel.org, efault@gmx.de Subject: Re: [PATCH 2/7] rcu: limit PREEMPT_RCU configurations Message-ID: <20241010102657.H7HpIbVp@linutronix.de> References: <20241009165411.3426937-1-ankur.a.arora@oracle.com> <20241009165411.3426937-3-ankur.a.arora@oracle.com> <20241009180117.GS17263@noisy.programming.kicks-ass.net> <37af80bd-a54f-4ee4-9175-6f0f27b685a0@paulmck-laptop> <20241010063207.xIrynIqO@linutronix.de> <20241010081032.GA17263@noisy.programming.kicks-ass.net> <20241010091326.nK71dG4b@linutronix.de> <20241010100308.GE17263@noisy.programming.kicks-ass.net> 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 Content-Transfer-Encoding: quoted-printable In-Reply-To: <20241010100308.GE17263@noisy.programming.kicks-ass.net> On 2024-10-10 12:03:08 [+0200], Peter Zijlstra wrote: > >=20 > > I can't deselect CONFIG_PREEMPT_RCU=3Dy. This is because LAZY selects > > PREEMPT_BUILD and PREEMPT_RCU selects itself once PREEMPTION is on. >=20 > Oh, the entry isn't user selectable? Fix that perhaps? >=20 > - bool > + bool "Use preemptible RCU" >=20 > Or something along those lines -- I forever forget how Kconfig works. Oh. Well, yes. If we do this then it becomes suddenly selectable and half of the series makes sense=E2=80=A6 But as you said, this complicates things.=20 Sebastian