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=-6.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 0F158C432BE for ; Wed, 18 Aug 2021 08:05:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECA216108B for ; Wed, 18 Aug 2021 08:05:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239270AbhHRIFh (ORCPT ); Wed, 18 Aug 2021 04:05:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:56728 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239112AbhHRIDt (ORCPT ); Wed, 18 Aug 2021 04:03:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4438D60EB5; Wed, 18 Aug 2021 08:03:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629273792; bh=5FpJoSsWAijWF1s+2IOmDRgN6RifYoWI9x/j4oSsSuo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eCjsWayN9W0nDaLKUgwVjLP37cSR+eyzVa0lW+E3UgnWM8Ed+d2Ht97prOHtEab2/ X/x71YQb858la7JnAqUYjETDTaVoI228RR2bOvzi2OgjMVIlBlbZ/8S+YfbPlvuRmA qDyrCBWHP1jugX/jb0oNaBEO+69SPhZPEsL2XnfzI82tOaQvvxwQWf2JUtBdrTIfce C/L6LJmsBpGkFD6E+64WmOyCKq09uOEPezgI9Hl0j2zREAGQdwlgdGVajFmuLq70Dg dLof8zrC4r3wJKXv/W4ZxGmO8mrOtxCLU11Mxet2Amkm8KUuNk49BpAAlV2VYx+8An Dgwl0rIg9ooWw== Date: Wed, 18 Aug 2021 11:03:09 +0300 From: Leon Romanovsky To: Jakub Kicinski Cc: "David S . Miller" , Guangbin Huang , Jacob Keller , Jiri Pirko , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Salil Mehta , Shannon Nelson , Yisen Zhuang , Yufeng Mo Subject: Re: [PATCH net-next 3/6] devlink: Count struct devlink consumers Message-ID: References: <20210816084741.1dd1c415@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210816090700.313a54ba@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210816090700.313a54ba@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 16, 2021 at 09:07:00AM -0700, Jakub Kicinski wrote: > On Mon, 16 Aug 2021 18:53:45 +0300 Leon Romanovsky wrote: > > On Mon, Aug 16, 2021 at 08:47:41AM -0700, Jakub Kicinski wrote: > > > On Sat, 14 Aug 2021 12:57:28 +0300 Leon Romanovsky wrote: > > > > From: Leon Romanovsky > > > > > > > > The struct devlink itself is protected by internal lock and doesn't > > > > need global lock during operation. That global lock is used to protect > > > > addition/removal new devlink instances from the global list in use by > > > > all devlink consumers in the system. > > > > > > > > The future conversion of linked list to be xarray will allow us to > > > > actually delete that lock, but first we need to count all struct devlink > > > > users. > > > > > > Not a problem with this set but to state the obvious the global devlink > > > lock also protects from concurrent execution of all the ops which don't > > > take the instance lock (DEVLINK_NL_FLAG_NO_LOCK). You most likely know > > > this but I thought I'd comment on an off chance it helps. > > > > The end goal will be something like that: > > 1. Delete devlink lock > > 2. Rely on xa_lock() while grabbing devlink instance (past devlink_try_get) > > 3. Convert devlink->lock to be read/write lock to make sure that we can run > > get query in parallel. > > 4. Open devlink netlink to parallel ops, ".parallel_ops = true". > > IIUC that'd mean setting eswitch mode would hold write lock on > the dl instance. What locks does e.g. registering a dl port take > then? write lock, because we are adding port to devlink->port_list. 9099 int devlink_port_register(struct devlink *devlink, 9100 struct devlink_port *devlink_port, 9101 unsigned int port_index) 9102 { ... 9115 list_add_tail(&devlink_port->list, &devlink->port_list);