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[23.128.96.18]) by mx.google.com with ESMTP id cd8si1153138ejb.627.2020.10.20.02.54.23; Tue, 20 Oct 2020 02:54:45 -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=@infradead.org header.s=merlin.20170209 header.b=tQbpYEWM; 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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405042AbgJTHbO (ORCPT + 99 others); Tue, 20 Oct 2020 03:31:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59806 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731247AbgJTHbO (ORCPT ); Tue, 20 Oct 2020 03:31:14 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 084D5C061755; Tue, 20 Oct 2020 00:31:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=0jpAo9lbXaLZETK0hjbBwDIDeTjw7Zq4maw1xDTUWIc=; b=tQbpYEWMgnzikItrfiwfOOp1g+ Hd3DMlLkRHGio/v1DuIL4w/ZAhR1TJaN9LYf5L9MLZ37bm77a22hC17TpTZQLpR8akbcFs+xqgZ5N 9P7q1PoT3Yt9VbmxA6H9h4ifUl+hXWPZd2n1Rw4RIe/iX9qAGgrNo+n7k90EQWCbdOwmll3sd5oSh TGTLXFWSqvLTMB0Ta413MhP6c/DZP5f8UfC2VqJ4C86Rj85LEzIuyBrGUxES/j9yVcek8fmgiaQXj 8kES1fOrNourzGZJ9CJhi4cPcQr0LgPKv6zmLw1n0E4SmQkhKRMS76Fyz2qeteH2DEblFpN8J3rfE 2VGekPFA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kUm6j-0000je-1t; Tue, 20 Oct 2020 07:30:57 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 4DF333011FE; Tue, 20 Oct 2020 09:30:55 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 3617E2B785033; Tue, 20 Oct 2020 09:30:55 +0200 (CEST) Date: Tue, 20 Oct 2020 09:30:55 +0200 From: Peter Zijlstra To: Marcelo Tosatti Cc: Nitesh Narayan Lal , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, intel-wired-lan@lists.osuosl.org, frederic@kernel.org, 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: <20201020073055.GY2611@hirez.programming.kicks-ass.net> 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> <20201019140005.GB17287@fuller.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201019140005.GB17287@fuller.cnet> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 19, 2020 at 11:00:05AM -0300, Marcelo Tosatti wrote: > > So I think it is important to figure out what that driver really wants > > in the nohz_full case. If it wants to retain N interrupts per CPU, and > > only reduce the number of CPUs, the proposed interface is wrong. > > It wants N interrupts per non-isolated (AKA housekeeping) CPU. Then the patch is wrong and the interface needs changing from @min_vecs, @max_vecs to something that expresses the N*nr_cpus relation.