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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 C954FC433E7 for ; Fri, 28 Aug 2020 08:59:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 993FE2071B for ; Fri, 28 Aug 2020 08:59:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="z9wEYcR8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728814AbgH1I7t (ORCPT ); Fri, 28 Aug 2020 04:59:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726010AbgH1I7q (ORCPT ); Fri, 28 Aug 2020 04:59:46 -0400 Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F08B0C06121B for ; Fri, 28 Aug 2020 01:59:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=4eqhOxy9cHFi0VijKDUn9S8u6mI/BeSMcijpmCfnCcg=; b=z9wEYcR8mtnpcP4B+bLEpsPrXS P5a/nHnhKUSPzy9w/s/ZaMGfvktkmv1+iKxGyKWSIxhYdsjojtO7p1FfZPMRdr6cGBEjbSQtNEPr+ Sg8OAa5q+0RLtg09Poimi2ZemkjTz+eehOYYz8PDhtUKV7CbaT2ujTS0yZmWJg7r3TyFkRcdDVz+U y30foQNrtqoiZZN7vknePofxRyLorr3xkjzaFy75C+9ZlOu6eDpy79qHLkMdgce+KvROqaz9EGDW7 7MdZOC9rJRfX1NKXrZRP0Y/RIUcI07cVNexY6bHk8K9qPMEOR+Uf+EvEdN9YWJ9BcPiYhjqxVrB3R 9LTYUIPg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kBaEV-0007t9-TI; Fri, 28 Aug 2020 08:59:40 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 97670300238; Fri, 28 Aug 2020 10:59:38 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 503782C56E64B; Fri, 28 Aug 2020 10:59:38 +0200 (CEST) Date: Fri, 28 Aug 2020 10:59:38 +0200 From: peterz@infradead.org To: "Ahmed S. Darwish" Cc: Ingo Molnar , Will Deacon , Thomas Gleixner , "Sebastian A. Siewior" , "Paul E. McKenney" , Steven Rostedt , LKML Subject: Re: [PATCH v1 4/5] seqlock: seqcount_LOCKTYPE_t: Introduce PREEMPT_RT support Message-ID: <20200828085938.GS1362448@hirez.programming.kicks-ass.net> References: <20200519214547.352050-1-a.darwish@linutronix.de> <20200828010710.5407-1-a.darwish@linutronix.de> <20200828010710.5407-5-a.darwish@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200828010710.5407-5-a.darwish@linutronix.de> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 28, 2020 at 03:07:09AM +0200, Ahmed S. Darwish wrote: > +#define __SEQ_RT IS_ENABLED(CONFIG_PREEMPT_RT) > + > +SEQCOUNT_LOCKTYPE(raw_spinlock, raw_spinlock_t, false, s->lock, raw_spin, raw_spin_lock(s->lock)) > +SEQCOUNT_LOCKTYPE(spinlock, spinlock_t, __SEQ_RT, s->lock, spin, spin_lock(s->lock)) > +SEQCOUNT_LOCKTYPE(rwlock, rwlock_t, __SEQ_RT, s->lock, read, read_lock(s->lock)) > +SEQCOUNT_LOCKTYPE(mutex, struct mutex, true, s->lock, mutex, mutex_lock(s->lock)) > +SEQCOUNT_LOCKTYPE(ww_mutex, struct ww_mutex, true, &s->lock->base, ww_mutex, ww_mutex_lock(s->lock, NULL)) Ooh, reading is hard, but ^^^^ you already have that. > +/* > + * Automatically disable preemption for seqcount_LOCKTYPE_t writers, if the > + * associated lock does not implicitly disable preemption. > + * > + * Don't do it for PREEMPT_RT. Check __SEQ_LOCK(). > + */ > +#define __seq_enforce_preemption_protection(s) \ > + (!IS_ENABLED(CONFIG_PREEMPT_RT) && __seqcount_lock_preemptible(s)) Then what is this doing ?!? I'm confused now.