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=-3.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 9860AC433DF for ; Thu, 28 May 2020 00:33:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5CCEA207CB for ; Thu, 28 May 2020 00:33:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rxHsPdkL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725941AbgE1AdP (ORCPT ); Wed, 27 May 2020 20:33:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725267AbgE1AdP (ORCPT ); Wed, 27 May 2020 20:33:15 -0400 Received: from mail-io1-xd44.google.com (mail-io1-xd44.google.com [IPv6:2607:f8b0:4864:20::d44]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 20AADC05BD1E for ; Wed, 27 May 2020 17:33:15 -0700 (PDT) Received: by mail-io1-xd44.google.com with SMTP id c8so7777549iob.6 for ; Wed, 27 May 2020 17:33:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=k/vP5W2oMukw5SIwIRY9OsaBo8uyFKNFoJtfdNmBMYk=; b=rxHsPdkLq1ts/2tzkmOe4WkG1FvNXDNy/yZj1s9RpNaRLtuPOc8VNxOIC5tiY547dT N5ESj2CYtY7NUl+3UkYEJO4Gzlbc295oM92aQ89gdOV4gPmJOsnXfUuGsUf7LpXelUmQ xH7YEu+CbAqBmB+ZQyPNdh80CeiqpLhRPHiMiGFQB2zOxRDHigMJeJmt3Q4NvN5ovgUP E3pW3RIeGbdWoCyjyJsVidjYc/QNS33W8QrCyQLkQGQDmGrzNSyNrwb3KYwxucJ0FG/v by+7XyAh5WOsMnr+ZW3T81qrYltgdBf2LwWgfqEMa7EI/LI8yCBbMn8ic59jmxJCkEzE XJeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=k/vP5W2oMukw5SIwIRY9OsaBo8uyFKNFoJtfdNmBMYk=; b=IUKhPPB2WY3ThHM3NvpTFrF4GKhVyfSzjTD2++iqEosAYOOpvbmBz7PJM8QcEKPfKB DXbcPQhi7SNFeI38Mo205n18jMaM7N01SljtpQbq8P2Uq7iJwuyNCrE1kVxMrna1F8c9 wTVHtAKJSlYAYETmWLURS76FEQilDkZXaGG6dxENrGAtg73WBrgVBO6lHbGmUx0ZY49z t2KhepJd6jpBC+lbWcGYUAMja5Fx+x7wzb+/Q1riWp2acHlclqlrQOp91b25AjG94PwG sWVcz00Q/VwTRFdv/l1oDKyJ80yp8mc9rFTFSejRhO40lM21lgFbk5nMbakuSAzq6yf0 r7Tg== X-Gm-Message-State: AOAM530piFlfPGVwGMcoX/jSDtfUOXOp5BtRuKVoVZ6HwU9QmHSfYrAo wehAVDHKHg19fcWrWDCyoaTTzjBa3cQN9X4BOdv4LQ== X-Google-Smtp-Source: ABdhPJyvOD2zVm2shSVFxqad3tbL55Lbgi4E5Mksvhir84sQrGtDQMgQRsvCi9Ie3v8iz1Kj7e961LqxAyM5s/g8fhE= X-Received: by 2002:a5e:a61a:: with SMTP id q26mr417152ioi.207.1590625994586; Wed, 27 May 2020 17:33:14 -0700 (PDT) MIME-Version: 1.0 References: <20200527194633.1660952-1-bigeasy@linutronix.de> <20200527194633.1660952-3-bigeasy@linutronix.de> In-Reply-To: <20200527194633.1660952-3-bigeasy@linutronix.de> From: Lai Jiangshan Date: Thu, 28 May 2020 08:33:03 +0800 Message-ID: Subject: Re: [PATCH v2 2/2] workqueue: Convert the pool::lock and wq_mayday_lock to raw_spinlock_t To: Sebastian Andrzej Siewior Cc: LKML , Tejun Heo , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Linus Torvalds Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 28, 2020 at 3:47 AM Sebastian Andrzej Siewior wrote: > > The workqueue code has it's internal spinlocks (pool::lock), which > are acquired on most workqueue operations. These spinlocks are > converted to 'sleeping' spinlocks on a RT-kernel. > > Workqueue functions can be invoked from contexts which are truly atomic > even on a PREEMPT_RT enabled kernel. Taking sleeping locks from such > contexts is forbidden. > > The pool::lock hold times are bound and the code sections are > relatively short, which allows to convert pool::lock and as a > consequence wq_mayday_lock to raw spinlocks which are truly spinning > locks even on a PREEMPT_RT kernel. > > With the previous conversion of the manager waitqueue to a simple > waitqueue workqueues are now fully RT compliant. > > Signed-off-by: Sebastian Andrzej Siewior > --- > kernel/workqueue.c | 176 ++++++++++++++++++++++----------------------- > 1 file changed, 88 insertions(+), 88 deletions(-) > Reviewed-by: Lai Jiangshan