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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 5C9B4C48BE3 for ; Sat, 22 Jun 2019 00:01:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3AF1620881 for ; Sat, 22 Jun 2019 00:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726075AbfFVABT (ORCPT ); Fri, 21 Jun 2019 20:01:19 -0400 Received: from mga11.intel.com ([192.55.52.93]:10826 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726070AbfFVABT (ORCPT ); Fri, 21 Jun 2019 20:01:19 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Jun 2019 17:01:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,402,1557212400"; d="scan'208";a="163039686" Received: from megha-z97x-ud7-th.sc.intel.com ([143.183.85.162]) by orsmga003.jf.intel.com with ESMTP; 21 Jun 2019 17:01:18 -0700 Message-ID: <1561163018.12836.1.camel@intel.com> Subject: Re: [RFC V1 0/6] Introduce dynamic allocation/freeing of MSI-X vectors From: Megha Dey To: bhelgaas@google.com, linux-pci@vger.kernel.org Cc: ashok.raj@intel.com, jacob.jun.pan@linux.intel.com Date: Fri, 21 Jun 2019 17:23:38 -0700 In-Reply-To: <1560981824-3966-1-git-send-email-megha.dey@linux.intel.com> References: <1560981824-3966-1-git-send-email-megha.dey@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.18.5.2-0ubuntu3.2 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, 2019-06-19 at 15:03 -0700, Megha Dey wrote: > Currently, MSI-X vector enabling and allocation for a PCIe device is > static i.e. a device driver gets only one chance to enable a specific > number of MSI-X vectors, usually during device probe. Also, in many > cases, drivers usually reserve more than required number of vectors > anticipating their use, which unnecessarily blocks resources that > could have been made available to other devices. Lastly, there is no > way for drivers to reserve more vectors, if the MSI-x has already > been > enabled for that device. >   > Hence, a dynamic MSI-X kernel infrastructure can benefit drivers by > deferring MSI-X allocation to post probe phase, where actual demand > information is available. >   > This patchset enables the dynamic allocation/de-allocation of MSI-X > vectors by introducing 2 new APIs: > pci_alloc_irq_vectors_dyn() and pci_free_irq_vectors_grp(): > > We have had requests from some of the NIC/RDMA users who have lots of > interrupt resources and would like to allocate them on demand, > instead of using an all or none approach. > > The APIs are fairly well tested (multiple allocations/deallocations), > but we have no early adopters yet. Hence, sending this series as an > RFC for review and comments. > > The patches are based out of Linux 5.2-rc5. I have resent the patches to include LKML. https://lkml.org/lkml/2019/6/21/923 > > Megha Dey (6): >   PCI/MSI: New structures/macros for dynamic MSI-X allocation >   PCI/MSI: Dynamic allocation of MSI-X vectors by group >   x86: Introduce the dynamic teardown function >   PCI/MSI: Introduce new structure to manage MSI-x entries >   PCI/MSI: Free MSI-X resources by group >   Documentation: PCI/MSI: Document dynamic MSI-X infrastructure > >  Documentation/PCI/MSI-HOWTO.txt |  38 +++++ >  arch/x86/include/asm/x86_init.h |   1 + >  arch/x86/kernel/x86_init.c      |   6 + >  drivers/pci/msi.c               | 363 > +++++++++++++++++++++++++++++++++++++--- >  drivers/pci/probe.c             |   9 + >  include/linux/device.h          |   3 + >  include/linux/msi.h             |  13 ++ >  include/linux/pci.h             |  61 +++++++ >  kernel/irq/msi.c                |  34 +++- >  9 files changed, 497 insertions(+), 31 deletions(-) >