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 57F35C432BE for ; Mon, 16 Aug 2021 16:07:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3FA3160F58 for ; Mon, 16 Aug 2021 16:07:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230224AbhHPQHf (ORCPT ); Mon, 16 Aug 2021 12:07:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:48570 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229621AbhHPQHd (ORCPT ); Mon, 16 Aug 2021 12:07:33 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6C8346056B; Mon, 16 Aug 2021 16:07:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1629130021; bh=dQ7YdQ2ihh87LThyE6YAzcRBdsJeA/gOE3NhxEzSMgY=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=lVfcuZvRIc5hRBNPL9PCCiPON7jp6Ak1mRU0mhJwTdJK0KONo78N3qaCWN9CvUXA4 8uGhdt/P9O6QCFDYyzEiGnDoBdVuDwrHsAIbgu4yrAldXNF2WUw3SAfepnUe31Edgm v0WZb2VRhDAGLxMiW9p07N9YUoxQD/sSjIO3gE5U1HfGMqYbXcBR3A+eWqK9Pf0NWj 32RjGSAixHY10CnCvOBOUSzn6RflfHnXPZl1h8J+VnkB/GDviL1LOi00pm4m1tIQwg 2gtt2YvefCj1eaqCz743ZRH84PbcAP+J2oXlUG37Hfxr5uuiFDc2KzY+uZHooezl8R e552YDmXKOY2A== Date: Mon, 16 Aug 2021 09:07:00 -0700 From: Jakub Kicinski To: Leon Romanovsky 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: <20210816090700.313a54ba@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> In-Reply-To: References: <20210816084741.1dd1c415@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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?