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=-18.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 BD387C4338F for ; Wed, 4 Aug 2021 23:34:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C0C0610FC for ; Wed, 4 Aug 2021 23:34:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235719AbhHDXfD (ORCPT ); Wed, 4 Aug 2021 19:35:03 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47399 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235323AbhHDXfB (ORCPT ); Wed, 4 Aug 2021 19:35:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1628120087; 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=VQv4qZvsh4gqGG12A1+aEgDS91kf49v/O6T32Q2bwtM=; b=bk5oV7Cn1UcN41YmUVaOWLYLnlTUR0jAp6soqdjhY7GTyhBxIK0XIYJzSYia4WSXP+g/gs yJshKlS6HzL0qIYYjHnWrGbBtmMCEnqCxCtDWF8OLDqg1Opyj1WNN6QYFf+zTlktevMtoZ yGnVvoXWSTkvjah6UMemPBvvuxHT+Y8= Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-203-nYKAoBVKObOHMUAcS7qKnA-1; Wed, 04 Aug 2021 19:34:44 -0400 X-MC-Unique: nYKAoBVKObOHMUAcS7qKnA-1 Received: by mail-qk1-f198.google.com with SMTP id b190-20020a3767c70000b02903ca0967b842so1481697qkc.9 for ; Wed, 04 Aug 2021 16:34:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:subject:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=VQv4qZvsh4gqGG12A1+aEgDS91kf49v/O6T32Q2bwtM=; b=rnxYX1rHC0pvnulN0puLcOAZ1QoCzDFtNMOTZf1FKtQlQSXLFW9VjpyRxk3G8oOFcL cMuiMfz8YX0dF3QKYZrK0eFrpELSDmOB8VNsGwiSPBd0fZzgwBKQy436d+dxm7KyWMXO KxD5xCOFADq0uVVfjCv6+CfP1onJkyGa8igy7EkAjH90DZebbewzwD9xbK48pc66ezSK GhgXXrisFcK1nCY/LrHn+B8LXodTTzM/iQFZWLX+d+5bN2Fk1kiZ36o7otp7aYjUIO25 GsKpmOIiJb4nJjriR4cFv3hr4iXW9lNwMQ+ToUGWNhJdnSl+fsQRDTgTtm7pdz3OKRBI 7OPg== X-Gm-Message-State: AOAM531xXr1VvExsGBARN4t+JjlGXs3cU0Zw+4+J3+jgqlH2pBWxlrWE bg0kCFP3iKUYHrLUnZq0PaL2l9JfiSEmHfHByb0rG0bnkzJrJc6enMPUMd1s/Var/MzCZuEg2i2 1sFltidFBoDHB6CruN+AUqb2F X-Received: by 2002:a05:622a:104a:: with SMTP id f10mr1945495qte.340.1628120084415; Wed, 04 Aug 2021 16:34:44 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwl9rRdjxepiOiyYQS7TcrkbqZpMoDI0ChGVDRK0W7wLv1R/j1RPQNuuHd8hbeeRX1LcABeDg== X-Received: by 2002:a05:622a:104a:: with SMTP id f10mr1945482qte.340.1628120084211; Wed, 04 Aug 2021 16:34:44 -0700 (PDT) Received: from llong.remote.csb ([2601:191:8500:76c0::cdbc]) by smtp.gmail.com with ESMTPSA id q194sm2224297qke.83.2021.08.04.16.34.43 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 04 Aug 2021 16:34:43 -0700 (PDT) From: Waiman Long X-Google-Original-From: Waiman Long Subject: Re: [patch 30/63] locking/spinlock: Provide RT variant To: Thomas Gleixner , LKML Cc: Peter Zijlstra , Ingo Molnar , Juri Lelli , Steven Rostedt , Daniel Bristot de Oliveira , Will Deacon , Boqun Feng , Sebastian Andrzej Siewior , Davidlohr Bueso References: <20210730135007.155909613@linutronix.de> <20210730135206.865728220@linutronix.de> Message-ID: <4fa5ec01-ff09-16f3-e1d6-42431036f554@redhat.com> Date: Wed, 4 Aug 2021 19:34:42 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <20210730135206.865728220@linutronix.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/30/21 9:50 AM, Thomas Gleixner wrote: > From: Thomas Gleixner > > Provide the actual locking functions which make use of the general and > spinlock specific rtmutex code. > > Signed-off-by: Thomas Gleixner > --- > kernel/locking/Makefile | 1 > kernel/locking/spinlock_rt.c | 128 +++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 129 insertions(+) > create mode 100644 kernel/locking/spinlock_rt.c > --- > --- a/kernel/locking/Makefile > +++ b/kernel/locking/Makefile > @@ -25,6 +25,7 @@ obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_ > obj-$(CONFIG_PROVE_LOCKING) += spinlock.o > obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o > obj-$(CONFIG_RT_MUTEXES) += rtmutex_api.o > +obj-$(CONFIG_PREEMPT_RT) += spinlock_rt.o > obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o > obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o > obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o > --- /dev/null > +++ b/kernel/locking/spinlock_rt.c > @@ -0,0 +1,128 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * PREEMPT_RT substitution for spin/rw_locks > + * > + * spin_lock and rw_lock on RT are based on rtmutex with a few twists to > + * resemble the non RT semantics > + * > + * - Contrary to a plain rtmutex, spin_lock and rw_lock are state > + * preserving. The task state is saved before blocking on the underlying > + * rtmutex and restored when the lock has been acquired. Regular wakeups > + * during that time are redirected to the saved state so no wake up is > + * missed. > + * > + * - Non RT spin/rw_locks disable preemption and evtl. interrupts. "evtl."? Cheers, Longman