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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 746A9CA9EB0 for ; Sun, 3 Nov 2019 19:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5078721929 for ; Sun, 3 Nov 2019 19:02:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728069AbfKCTCn (ORCPT ); Sun, 3 Nov 2019 14:02:43 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:49694 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727322AbfKCTCn (ORCPT ); Sun, 3 Nov 2019 14:02:43 -0500 Received: from callcc.thunk.org (ip-12-2-52-196.nyc.us.northamericancoax.com [196.52.2.12]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id xA3J1gL9011616 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 3 Nov 2019 14:01:43 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id 71748420311; Sun, 3 Nov 2019 14:01:41 -0500 (EST) Date: Sun, 3 Nov 2019 14:01:41 -0500 From: "Theodore Y. Ts'o" To: Jan Kara Cc: linux-ext4@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Ingo Molnar , Steven Rostedt , Anna-Maria Gleixner , Julia Cartwright Subject: Re: [PATCH 0/7 v2] jbd2: Bit spinlock conversions Message-ID: <20191103190141.GA8037@mit.edu> References: <20190809124233.13277-1-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190809124233.13277-1-jack@suse.cz> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Fri, Aug 09, 2019 at 02:42:26PM +0200, Jan Kara wrote: > Hello, > > This series is derived from Thomas' series to get rid of bit spinlocks in > buffer head code. These patches convert BH_State bit spinlock to an ordinary > spinlock inside struct journal_head and somewhat reduce the critical section > under BH_JournalHead bit spinlock so that it is fine for RT. > > Motivation from original Thomas' series: > > Bit spinlocks are problematic if PREEMPT_RT is enabled. They disable > preemption, which is undesired for latency reasons and breaks when regular > spinlocks are taken within the bit_spinlock locked region because regular > spinlocks are converted to 'sleeping spinlocks' on RT. > > Bit spinlocks are also not covered by lock debugging, e.g. lockdep. With > the spinlock substitution in place, they can be exposed via a new config > switch: CONFIG_DEBUG_BIT_SPINLOCKS. > > Ted, can you pick up these patches? Thanks! I've landed this patch set on the ext4 git tree. Thanks! - Ted