From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8216C3F4DFB for ; Fri, 17 Jul 2026 10:59:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784285975; cv=none; b=J45c6Tw9bRnAfTfTB5nAfmnd86hJd9bH8M6/XPsRMZzrC2J/PTflD0vEpv1z6D6tLaTyX8FIA4Eue4OzfJQRIdQxUOt5uu9E0CpwkIn1A8kNDlEAtco18Y7xmM0ZuESSPl22bmZfeFtdpISFqhPVvOYHdBJPjxd/zQy3ChNcG5g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784285975; c=relaxed/simple; bh=alcvjuXWrRHpr9OLd7CQULMzobeVgXJmSRC52fRTX/M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=B1KWSK1RnBYK0D51E8I1s5X4QPHqPTYacAmJPrww0rY1JrWxXXh4miQKqMYjXzPwE6uXSPIv+aaBK1Y1s6FeHEGw7oynoDe7VrhuFcQrGNTU0K0VMpue08rxTjbplUfaafQ32TS4DTOFybNJd9jIp1NdhKl7Be5DUb2uwRkiQuE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=F14+EDV7; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="F14+EDV7" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0604F1476; Fri, 17 Jul 2026 03:59:17 -0700 (PDT) Received: from J2N7QTR9R3 (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5F3B33F7D8; Fri, 17 Jul 2026 03:59:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784285961; bh=alcvjuXWrRHpr9OLd7CQULMzobeVgXJmSRC52fRTX/M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=F14+EDV7AKAoAU+DZ9uJKy0VETGQEuZuANb67jHrzicYmEq62BTk7iGIX9MatJkAM zYqxsM8ScNy7Xb76X+nQGg4yfSjYyL+j3V/9O/59hO8ummUomPoObOEhYiaLhR3zfm aM7iRDi6bwrjux7dPePorHMSvpAm7dFNrqyND9ho= Date: Fri, 17 Jul 2026 11:59:13 +0100 From: Mark Rutland To: Shrikanth Hegde Cc: linux-kernel@vger.kernel.org, frederic@kernel.org, jstultz@google.com, juri.lelli@redhat.com, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, vincent.guittot@linaro.org, vschneid@redhat.com Subject: Re: [PATCH 1/5] sched: dynamic: Make PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY Message-ID: References: <20260703133358.698078-1-mark.rutland@arm.com> <20260703133358.698078-2-mark.rutland@arm.com> <860baba7-e65d-463b-85cc-feb9c4f930c7@linux.ibm.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=us-ascii Content-Disposition: inline In-Reply-To: <860baba7-e65d-463b-85cc-feb9c4f930c7@linux.ibm.com> On Mon, Jul 06, 2026 at 10:06:29AM +0530, Shrikanth Hegde wrote: > On 7/3/26 7:03 PM, Mark Rutland wrote: > > On architectures which select ARCH_HAS_PREEMPT_LAZY, it has not been > > possible to select the NONE and VOLUNTARY preemption models since > > commit: > > > > 7dadeaa6e851 ("sched: Further restrict the preemption modes") > > > > ... which was merged in v7.0. > > > > All architectures which currently suppoort PREEMPT_DYNAMIC select > > s/suppoort/support Thanks; fixed locally now. [...] > > diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt > > index 88c594c6d7fcd..fb49424003b2b 100644 > > --- a/kernel/Kconfig.preempt > > +++ b/kernel/Kconfig.preempt > > @@ -129,6 +129,7 @@ config PREEMPTION > > config PREEMPT_DYNAMIC > > bool "Preemption behaviour defined on boot" > > depends on HAVE_PREEMPT_DYNAMIC > > + depends on ARCH_HAS_PREEMPT_LAZY > > select JUMP_LABEL if HAVE_PREEMPT_DYNAMIC_KEY > > select PREEMPT_BUILD > > default y if HAVE_PREEMPT_DYNAMIC_CALL > > > Can we update the help section bit? > > """ > The runtime overhead is negligible. > > Interesting if you want the same pre-built kernel should be used for > both Server and Desktop workloads. > """ > I think server meant preempt=none and desktop meant preempt=full/lazy there. No? I think that's the common case, yes. I think the existing wording isn't wrong, so I'm going to leave it as-is for now, given the wording change is logically separate from the other changes. [...] > other than that, it looks good to me. > > Reviewed-by: Shrikanth Hegde Thanks! Mark.