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a=ed25519-sha256; c=relaxed/relaxed; t=1772084256; s=strato-dkim-0003; d=xenosoft.de; h=In-Reply-To:Date:Message-ID:From:References:Cc:To:Subject:Cc:Date: From:Subject:Sender; bh=o0ysbZpfHQ3iRyOI9zvyJSu2mmeoVwkAQXPoR064I/g=; b=Svc+lW60q49CdUJ5bcoNJy1M52+9V962Cgw9+svMxUFsE6jn60QC2DgScZAPE5BOub 2v16jAFG/c9pwIdvavCg== X-RZG-AUTH: ":L2QefEenb+UdBJSdRCXu93KJ1bmSGnhMdmOod1DhGN0rBVhd9dFr4thIFiqT9BURIC+m6B7g" Received: from void-ppc.a-eon.tld by smtp.strato.de (RZmta 55.0.1 DYNA|AUTH) with ESMTPSA id e9337f21Q5batcH (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Thu, 26 Feb 2026 06:37:36 +0100 (CET) Subject: [Linux PPC] Disable PREEMPT To: "Christophe Leroy (CS GROUP)" , Shrikanth Hegde , linuxppc-dev , "kvm-ppc@vger.kernel.org" , Madhavan Srinivasan , Peter Zijlstra Cc: "R.T.Dickinson" , hypexed@yahoo.com.au, mad skateman , Christian Zigotzky References: <185d7a42-f7b4-44e1-a129-f5989d211c74@linux.ibm.com> <40154f6a-39da-959d-e039-5ab9ff62db3c@xenosoft.de> <709b864f-9daa-4a48-b3d6-39baedce63b2@linux.ibm.com> <843b7c60-23f1-47d0-b4e8-2147c3e40c23@linux.ibm.com> <2a27e6fc-7eb4-41a5-ba88-58f6a22625b5@xenosoft.de> <1d79ec6f-ce7f-4432-80e0-a54fa1668642@linux.ibm.com> <1c9b879a-7907-4849-a416-5df3db5617d6@kernel.org> From: Christian Zigotzky Organization: A-EON Open Source Message-ID: <34112e67-85a5-a380-a42b-24c6562d65be@xenosoft.de> Date: Thu, 26 Feb 2026 06:37:35 +0100 X-Mailer: BrassMonkey/33.9.1 Precedence: bulk X-Mailing-List: kvm-ppc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <1c9b879a-7907-4849-a416-5df3db5617d6@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 25/02/26 08:16, Christophe Leroy (CS GROUP) wrote: > +Peter > > Hi Christian, > > Le 25/02/2026 à 06:54, Christian Zigotzky a écrit : >> Hello, >> >> We were previously able to disable PREEMPT in the kernel >> configuration, but the latest kernels now enable it by default and it >> is no longer possible to disable it. >> >> Is it possible to let us decide whether to activate PREEMPT or not? > > Can you give more details on why you want to be able to deactivate > PREEMPT ? > > Read https://github.com/torvalds/linux/commit/7dadeaa6e851e I use PREEMPT_NONE kernels on my Linux PPC servers. (Without desktop) > > >> >> Currently we use the following revert patch for our non-preempt kernels. >> >> --- a/kernel/Kconfig.preempt    2026-02-14 10:06:32.000000000 +0000 >> +++ b/kernel/Kconfig.preempt    2026-02-08 21:03:27.000000000 +0000 >> @@ -16,13 +16,11 @@ config ARCH_HAS_PREEMPT_LAZY >> >>   choice >>       prompt "Preemption Model" >> -    default PREEMPT_LAZY if ARCH_HAS_PREEMPT_LAZY >>       default PREEMPT_NONE >> >>   config PREEMPT_NONE >>       bool "No Forced Preemption (Server)" >>       depends on !PREEMPT_RT >> -    depends on ARCH_NO_PREEMPT >>       select PREEMPT_NONE_BUILD if !PREEMPT_DYNAMIC >>       help >>         This is the traditional Linux preemption model, geared towards >> @@ -37,7 +35,6 @@ config PREEMPT_NONE >> >>   config PREEMPT_VOLUNTARY >>       bool "Voluntary Kernel Preemption (Desktop)" >> -    depends on !ARCH_HAS_PREEMPT_LAZY >>       depends on !ARCH_NO_PREEMPT >>       depends on !PREEMPT_RT >>       select PREEMPT_VOLUNTARY_BUILD if !PREEMPT_DYNAMIC >> >> --- >> >> Thanks in advance, >> >> Christian >> > -- Sent with BrassMonkey 33.9.1 (https://github.com/chzigotzky/Web-Browsers-and-Suites-for-Linux-PPC/releases/tag/BrassMonkey_33.9.1)