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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C2591C433E9 for ; Wed, 17 Mar 2021 20:22:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 830D564F0C for ; Wed, 17 Mar 2021 20:22:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233285AbhCQUV2 (ORCPT ); Wed, 17 Mar 2021 16:21:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:45838 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233271AbhCQUVG (ORCPT ); Wed, 17 Mar 2021 16:21:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616012463; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AlpPY6ekxOjyJjbkL7CucsibdK3fSyFUbHC5754coLk=; b=fr5z1g8kcIXZi8jQtg0UhVgyruC7v3tLUvpRM3NpRZYZMnRmIwCqpEGUIaL6ZSHh1a7ntt 940GjXeVPfRiMfYaanxN3ypiWbYPY7K5BBYQNKXMdlLG5oe+SaqpOnhd63z8LTZDYT0JAI /1aJorTAqWkZDet9FUu6Z1NiPjQ0pjw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-335-aFeaLzXvMFC2jr6ROMV3iQ-1; Wed, 17 Mar 2021 16:21:01 -0400 X-MC-Unique: aFeaLzXvMFC2jr6ROMV3iQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ACDE71043360; Wed, 17 Mar 2021 20:20:59 +0000 (UTC) Received: from llong.remote.csb (ovpn-117-171.rdu2.redhat.com [10.10.117.171]) by smtp.corp.redhat.com (Postfix) with ESMTP id 231F960C13; Wed, 17 Mar 2021 20:20:59 +0000 (UTC) Subject: Re: [tip: locking/urgent] locking/ww_mutex: Treat ww_mutex_lock() like a trylock To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, Ingo Molnar , x86@kernel.org References: <20210316153119.13802-4-longman@redhat.com> <161598470197.398.8903908266426306140.tip-bot2@tip-bot2> <36d26109-f08a-6254-2fd3-ad1a28fcc260@redhat.com> <20210317195834.GV4746@worktop.programming.kicks-ass.net> From: Waiman Long Organization: Red Hat Message-ID: <5533bdea-4250-759d-1a5d-007914aad2ff@redhat.com> Date: Wed, 17 Mar 2021 16:20:58 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210317195834.GV4746@worktop.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/17/21 3:58 PM, Peter Zijlstra wrote: > On Wed, Mar 17, 2021 at 02:32:27PM -0400, Waiman Long wrote: >> On 3/17/21 1:45 PM, Peter Zijlstra wrote: >>>> +# define __DEP_MAP_WW_MUTEX_INITIALIZER(lockname, class) \ >>>> + , .dep_map = { \ >>>> + .key = &(class).mutex_key, \ >>>> + .name = (class).mutex_name, \ >>> ,name = #class "_mutex", \ >>> >>> and it 'works', but shees! >> The name string itself may be duplicated for multiple instances of >> DEFINE_WW_MUTEX(). Do you want to keep DEFINE_WW_MUTEX() or just use >> ww_mutex_init() for all? > So linkers can merge literals, but no guarantee. But yeah, lets just > kill the thing, less tricky macro crud to worry about. > Good, just to confirm the right way to move forward. Cheers, Longman