From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 47278267AF4 for ; Tue, 20 May 2025 11:57:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747742245; cv=none; b=Thw3CZDVi0OZRM1P9DXKrHQxGPkH8RKSHlz9aO1MS+te0N0Nfzvse3QeRrEOTr29PU8RoJWBU25Kz6nwtcPs/dsmcC/EgwZHSHrh2jOg66AtoTagpXHj4j8J+cuXrivKkj8LzEsX/mSjDDGQptmRrL73zpLLupBj41aFZMALl/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747742245; c=relaxed/simple; bh=JA5IURh3R/rz1YWIDzC4eb8tG4fWBRz24TVzdqmCUIY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=iKVGiXFalP5L+chGN72JCDoUH33C62Uqpt27Mfy2iHWb2D7rUPsnO1wTZ7O7FVpsjG/8wOjgAqxXAJiApYR7XI8sv/yyUDRSGtkMEsjCYg6PFuT1quXSQ6K5iYLsu6L+ZoyZUp00s3D1EA5w6Kv7rmFOQQFx8vIEazCKy28Hwr4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jzK0MJjY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jzK0MJjY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58B2EC4CEE9; Tue, 20 May 2025 11:57:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747742244; bh=JA5IURh3R/rz1YWIDzC4eb8tG4fWBRz24TVzdqmCUIY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jzK0MJjYXuvKtQhEAoJHYz55uFH7Pa7cnl315wCeKnDgdRBmPMhYs7hu38laa4ILd npwDGuM+qwnnawNQKjyfjpHTG0mmhFI0+yAt8q2GFIkVZHby3DQfnI0sR3FQZkdWjl qE7n1GBpplxbmNYcONc6Qrx/9TH5elOp1e7Wxe39JkbsOI5fNfG+08nBNCjkXctJU5 CcLqNPVBdTVyzv/eanvHGlt26E28gm2NKscqxNcWcxtwjtMoxYvDFITDLnj1rTS9Tf dO0jkecc6qTJjRX3UOq9hS/M61lEu6eqJSpCz60BJTph5VtalApkZd7Orl9ZZy0odL /Y5COYvGDlvCg== Date: Tue, 20 May 2025 13:57:21 +0200 From: Frederic Weisbecker To: Gabriele Monaco Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Waiman Long Subject: Re: [PATCH v5 4/6] sched/isolation: Force housekeeping if isolcpus and nohz_full don't leave any Message-ID: References: <20250508145319.97794-8-gmonaco@redhat.com> <20250508145319.97794-12-gmonaco@redhat.com> <685cdf5db59a8aaf0b7c0d9847d109d878da039b.camel@redhat.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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <685cdf5db59a8aaf0b7c0d9847d109d878da039b.camel@redhat.com> Le Tue, May 20, 2025 at 01:17:20PM +0200, Gabriele Monaco a écrit : > The isolcpus parameter can be used like: > 1. isolcpus=1,2,3 > 2. isolcpus=domain,1,2,3 > 3. isolcpus=nohz,1,2,3 > 4. isolcpus=domain,nohz,1,2,3 > ... > > 1 and 2 are equivalent (e.g. if no mode is specified, that's domain > isolation), 3 is equivalent to nohz_full=1,2,3 and 4 is equivalent to > 1-2 in combination with nohz_full=1,2,3 > > Now, the code takes into account that there are 2 arguments that can > isolate (isolcpus and domain) and can be passed in any order, that > specific code guards against those two passing inconsistent maps, e.g.: > > isolcpus=nohz,0-4 nohz_full=5-8 > > Strictly speaking it's guarding for any other possible inconsistency > but I believe that's the only one actually achievable. > > Again, nothing forbids e.g. > > isolcpus=domain,0-4 nohz_full=5-8 > > since they're different isolation flags and that's allowed (not sure if > it really should be though). Duh, yes, it only refuse if the flags are common and masks are different. I seem to remember you already explained that to me last time and I already slapped my forehead. Prepare for me to ask the same question one more time in one week ;-) -- Frederic Weisbecker SUSE Labs