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[23.128.96.18]) by mx.google.com with ESMTP id w10si480340ejv.268.2020.10.19.19.57.37; Mon, 19 Oct 2020 19:57:58 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=XJywZspL; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729296AbgJSOVK (ORCPT + 99 others); Mon, 19 Oct 2020 10:21:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:46652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728311AbgJSOVK (ORCPT ); Mon, 19 Oct 2020 10:21:10 -0400 Received: from localhost (unknown [176.167.103.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1573D221FC; Mon, 19 Oct 2020 14:21:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603117269; bh=RlnJso2zV6UGQMDwIYMaQRuuJ80aQ8q0A0LxXDG7tv4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XJywZspLTypkshdONfdoa1utoSHmWb4+d0n5Tec0P7iNGTsqWi8YJESXtd6sJfdZB DpXfNpZASEUegzLyEFFoZfInWZ4/pchUsrcPmKsqRnL+4+U8jej3NAuI1pRF7L4keW FeHfiG+dE2x1m44G8c7ed3iEtTmP2g7bJvecX/x0= Date: Mon, 19 Oct 2020 16:21:06 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: Nitesh Narayan Lal , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, intel-wired-lan@lists.osuosl.org, mtosatti@redhat.com, sassmann@redhat.com, jesse.brandeburg@intel.com, lihong.yang@intel.com, helgaas@kernel.org, jeffrey.t.kirsher@intel.com, jacob.e.keller@intel.com, jlelli@redhat.com, hch@infradead.org, bhelgaas@google.com, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, thomas.lendacky@amd.com, jiri@nvidia.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, lgoncalv@redhat.com Subject: Re: [PATCH v4 4/4] PCI: Limit pci_alloc_irq_vectors() to housekeeping CPUs Message-ID: <20201019142106.GB34192@lothringen> References: <20200928183529.471328-1-nitesh@redhat.com> <20200928183529.471328-5-nitesh@redhat.com> <20201016122046.GP2611@hirez.programming.kicks-ass.net> <79f382a7-883d-ff42-394d-ec4ce81fed6a@redhat.com> <20201019111137.GL2628@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201019111137.GL2628@hirez.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 19, 2020 at 01:11:37PM +0200, Peter Zijlstra wrote: > > > And what are the (desired) semantics vs hotplug? Using a cpumask without > > > excluding hotplug is racy. > > > > The housekeeping_mask should still remain constant, isn't? > > In any case, I can double check this. > > The goal is very much to have that dynamically configurable. Right but unfortunately we are not there before a little while. And the existing code in these drivers allocating vectors doesn't even take into account hotplug as you spotted. So I agreed to let Nitesh fix this issue on top of the existing code until he can look into providing some infrastructure for these kind of vectors allocation. The first step would be to consolidate similar code from other drivers, then maybe handle hotplug and later dynamic housekeeping.