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 X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C291DC56201 for ; Mon, 26 Oct 2020 22:49:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 886D920795 for ; Mon, 26 Oct 2020 22:49:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="m7vXXWXX"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="nsEuqJwg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394731AbgJZWti (ORCPT ); Mon, 26 Oct 2020 18:49:38 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:43162 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390414AbgJZWti (ORCPT ); Mon, 26 Oct 2020 18:49:38 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1603752576; 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=ksDYXJPDBGDtncgmMUcP9mg1mza2LJA00t5oGzxZJYk=; b=m7vXXWXXxHdnndNtWQzlF5Od36id+ZmbnGgo3O8KuZgIQt8AscK7UpGXMljlrFEHLNBaxA YFgMa2sXy/Z8smqW8pTKT3fR27aNV9g1YXjR0uSFbgUiAyNFq7qZVyTPe+MmEYZIPU7JeY CZJPzsqK7IBdoJNDIZkkZEavoNHE1En/gpdaMaVi5G7CRSXFK/awLeOWDP6FMz5fSM7lrl qYHeVFPmmcBO/oIvuCQ6mLAn46sp74MiQkRAi4SPsaIWjn7MJDMCwDCCLHRtB78P/5y4jB er8LHo0C+LGGSmAolm/yXPk75p7DEBvjeRLowmPokxh6NBAtwJ480e622yAp7Q== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1603752576; 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=ksDYXJPDBGDtncgmMUcP9mg1mza2LJA00t5oGzxZJYk=; b=nsEuqJwgK8MU3fHK1KrFTAEeMjqWozGRv//N4pHuy/v6G6hN3DNpuuLWxfRIk3N7f1F1Mp ykp4Anes+d/b9tAg== To: Nitesh Narayan Lal , Jacob Keller , Marcelo Tosatti Cc: Peter Zijlstra , helgaas@kernel.org, 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, jeffrey.t.kirsher@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, Jakub Kicinski Subject: Re: [PATCH v4 4/4] PCI: Limit pci_alloc_irq_vectors() to housekeeping CPUs In-Reply-To: <959997ee-f393-bab0-45c0-4144c37b9185@redhat.com> References: <20201019111137.GL2628@hirez.programming.kicks-ass.net> <20201019140005.GB17287@fuller.cnet> <20201020073055.GY2611@hirez.programming.kicks-ass.net> <078e659e-d151-5bc2-a7dd-fe0070267cb3@redhat.com> <20201020134128.GT2628@hirez.programming.kicks-ass.net> <6736e643-d4ae-9919-9ae1-a73d5f31463e@redhat.com> <260f4191-5b9f-6dc1-9f11-085533ac4f55@redhat.com> <20201023085826.GP2611@hirez.programming.kicks-ass.net> <9ee77056-ef02-8696-5b96-46007e35ab00@redhat.com> <87ft6464jf.fsf@nanos.tec.linutronix.de> <20201026173012.GA377978@fuller.cnet> <875z6w4xt4.fsf@nanos.tec.linutronix.de> <86f8f667-bda6-59c4-91b7-6ba2ef55e3db@intel.com> <87v9ew3fzd.fsf@nanos.tec.linutronix.de> <85b5f53e-5be2-beea-269a-f70029bea298@intel.com> <87lffs3bd6.fsf@nanos.tec.linutronix.de> <959997ee-f393-bab0-45c0-4144c37b9185@redhat.com> Date: Mon, 26 Oct 2020 23:49:35 +0100 Message-ID: <875z6w38n4.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Oct 26 2020 at 18:22, Nitesh Narayan Lal wrote: > On 10/26/20 5:50 PM, Thomas Gleixner wrote: >> But I still think that for curing that isolation stuff we want at least >> some information from the driver. Alternative solution would be to grant >> the allocation of interrupts and queues and have some sysfs knob to shut >> down queues at runtime. If that shutdown results in releasing the queue >> interrupt (via free_irq()) then the vector exhaustion problem goes away. > > I think this is close to what I and Marcelo were discussing earlier today > privately. > > I don't think there is currently a way to control the enablement/disablement of > interrupts from the userspace. You cannot just disable the interrupt. You need to make sure that the associated queue is shutdown or quiesced _before_ the interrupt is shut down. Thanks, tglx