From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 972B0C433F5 for ; Fri, 6 May 2022 19:48:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1391912AbiEFTwR (ORCPT ); Fri, 6 May 2022 15:52:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242556AbiEFTwO (ORCPT ); Fri, 6 May 2022 15:52:14 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 13E264B40A for ; Fri, 6 May 2022 12:48:30 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1651866508; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=obKDPm1us147PjbB0DX4AOLNMPgBymj9mmgDJjujsNQ=; b=HioOdTsoFc6QL4Q5ukxv+Ntea8dHeHBk4X2FT+oa3bbwVlhaaalijyMz3Ud42vI0Xz+Pm5 5uNcxKXmjg9OVSDh0Dt4tYZQOtxWfVFjjhHrSpCQezPQxTgdp4FY13dtV9rXwDevFIpXv6 muaKmsTE1yrW4JvMj8a2VNOKwIw/8hiF4TH9d66KAra9PGXIcwgS+d6jJ9pIjFAO9TVsmJ 7WIXTpeAKzbt2/hokUTls/YOcFf5INx190TqnegdhNw+Iz7enysvt7LGD9aYjh0IdLT2O1 F9KOHoFhYxx5YN++nCtmpnJKTcTtL7nhOGwRsnjxvDLfRK1XRQCtPb9oaZBu4Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1651866508; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=obKDPm1us147PjbB0DX4AOLNMPgBymj9mmgDJjujsNQ=; b=PhVvmh62AnNYLXZZs9XTvL0zSLIZOMjOmiHCiiYPPKnVJ9DouHuXu7vrlN828CvNAlUl2q /dCD5SBWUsoH+LDA== To: Ricardo Neri , x86@kernel.org Cc: Tony Luck , Andi Kleen , Stephane Eranian , Andrew Morton , Joerg Roedel , Suravee Suthikulpanit , David Woodhouse , Lu Baolu , Nicholas Piggin , "Ravi V. Shankar" , Ricardo Neri , iommu@lists.linux-foundation.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, Ricardo Neri Subject: Re: [PATCH v6 01/29] irq/matrix: Expose functions to allocate the best CPU for new vectors In-Reply-To: <20220506000008.30892-2-ricardo.neri-calderon@linux.intel.com> References: <20220506000008.30892-1-ricardo.neri-calderon@linux.intel.com> <20220506000008.30892-2-ricardo.neri-calderon@linux.intel.com> Date: Fri, 06 May 2022 21:48:28 +0200 Message-ID: <878rreh27n.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ricardo, On Thu, May 05 2022 at 16:59, Ricardo Neri wrote: > Certain types of interrupts, such as NMI, do not have an associated vector. > They, however, target specific CPUs. Thus, when assigning the destination > CPU, it is beneficial to select the one with the lowest number of > vectors. Why is that beneficial especially in the context of a NMI watchdog which then broadcasts the NMI to all other CPUs? That's wishful thinking perhaps, but I don't see any benefit at all. > Prepend the functions matrix_find_best_cpu_managed() and > matrix_find_best_cpu_managed() The same function prepended twice becomes two functions :) > with the irq_ prefix and expose them for > IRQ controllers to use when allocating and activating vector-less IRQs. There is no such thing like a vectorless IRQ. NMIs have a vector. Can we please describe facts and not pulled out of thin air concepts which do not exist? Thanks, tglx