From patchwork Wed Mar 25 16:58:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Randy Dunlap X-Patchwork-Id: 1261552 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 48nZ9M2jsGz9sQx for ; Thu, 26 Mar 2020 03:59:51 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=Ny0TO9lE; dkim-atps=neutral Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 48nZ9M1tJZzDqbX for ; Thu, 26 Mar 2020 03:59:51 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=infradead.org (client-ip=2607:7c80:54:e::133; helo=bombadil.infradead.org; envelope-from=rdunlap@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=bombadil.20170209 header.b=Ny0TO9lE; dkim-atps=neutral Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 48nZ7l29YpzDqZT for ; Thu, 26 Mar 2020 03:58:25 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:References:Cc:To: Subject:Sender:Reply-To:Content-ID:Content-Description; bh=nzNtddxyHToIfzwzcRpU+rkJvFePaVcVMvDxhJ0zIm8=; b=Ny0TO9lEhbmvUL2PtdSbl/e3Gm dLHrOkD5v8ewIwjLPXGarl7V5+K4iXFzHb2IblMXtRLy0e1xYPfEYd/TNMgeQMms4qdMS3GnsSBzh MG4FkMj0CmZIJdF594Ere7tUatW2cpHFY1FN56RNDDvW3fQmt0gVnStPqemN2Xr9H/2N8GLHIr5Wg jCmOaOYFpQoZFzr/LNFj0CHFygyAwaMnjmIJLMM/2ZdRTd590pAvjPj/dIFmu4oG/94o0FTc9L0qs q8JUj6IqIVy73yedpWdJ2Myuil5rim24S7yVdJXA5SxDwBhAKySclpEAQs+h4mmF+uJG1N1o3ZfNM CTBQSfOQ==; Received: from [2601:1c0:6280:3f0::19c2] by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jH9M9-0002V3-KT; Wed, 25 Mar 2020 16:58:17 +0000 Subject: [PATCH v2] Documentation/locking/locktypes: minor copy editor fixes To: Thomas Gleixner , paulmck@kernel.org References: <20200323025501.GE3199@paulmck-ThinkPad-P72> <87r1xhz6qp.fsf@nanos.tec.linutronix.de> <20200325002811.GO19865@paulmck-ThinkPad-P72> <87wo78y5yy.fsf@nanos.tec.linutronix.de> From: Randy Dunlap Message-ID: Date: Wed, 25 Mar 2020 09:58:14 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <87wo78y5yy.fsf@nanos.tec.linutronix.de> Content-Language: en-US X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-ia64@vger.kernel.org, Peter Zijlstra , linux-pci@vger.kernel.org, Sebastian Siewior , Oleg Nesterov , Guo Ren , Joel Fernandes , Vincent Chen , Ingo Molnar , Davidlohr Bueso , linux-acpi@vger.kernel.org, Brian Cain , Jonathan Corbet , linux-hexagon@vger.kernel.org, "Rafael J. Wysocki" , linux-csky@vger.kernel.org, Linus Torvalds , Darren Hart , Zhang Rui , Len Brown , Fenghua Yu , Arnd Bergmann , linux-pm@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Greentime Hu , Bjorn Helgaas , Kurt Schwemmer , platform-driver-x86@vger.kernel.org, Kalle Valo , kbuild test robot , Felipe Balbi , Michal Simek , Tony Luck , Nick Hu , Geoff Levand , netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-wireless@vger.kernel.org, LKML , Davidlohr Bueso , Greg Kroah-Hartman , Logan Gunthorpe , "David S. Miller" , Andy Shevchenko Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: Randy Dunlap Minor editorial fixes: - add some hyphens in multi-word adjectives - add some periods for consistency - add "'" for possessive CPU's - capitalize IRQ when it's an acronym and not part of a function name Signed-off-by: Randy Dunlap Cc: Paul McKenney Cc: Thomas Gleixner Cc: Sebastian Siewior Cc: Joel Fernandes Cc: Ingo Molnar Cc: Peter Zijlstra Reviewed-by: Paul E. McKenney --- Documentation/locking/locktypes.rst | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) --- linux-next-20200325.orig/Documentation/locking/locktypes.rst +++ linux-next-20200325/Documentation/locking/locktypes.rst @@ -84,7 +84,7 @@ rtmutex RT-mutexes are mutexes with support for priority inheritance (PI). -PI has limitations on non PREEMPT_RT enabled kernels due to preemption and +PI has limitations on non-PREEMPT_RT-enabled kernels due to preemption and interrupt disabled sections. PI clearly cannot preempt preemption-disabled or interrupt-disabled @@ -150,7 +150,7 @@ kernel configuration including PREEMPT_R raw_spinlock_t is a strict spinning lock implementation in all kernels, including PREEMPT_RT kernels. Use raw_spinlock_t only in real critical -core code, low level interrupt handling and places where disabling +core code, low-level interrupt handling and places where disabling preemption or interrupts is required, for example, to safely access hardware state. raw_spinlock_t can sometimes also be used when the critical section is tiny, thus avoiding RT-mutex overhead. @@ -160,20 +160,20 @@ spinlock_t The semantics of spinlock_t change with the state of PREEMPT_RT. -On a non PREEMPT_RT enabled kernel spinlock_t is mapped to raw_spinlock_t +On a non-PREEMPT_RT-enabled kernel spinlock_t is mapped to raw_spinlock_t and has exactly the same semantics. spinlock_t and PREEMPT_RT ------------------------- -On a PREEMPT_RT enabled kernel spinlock_t is mapped to a separate +On a PREEMPT_RT-enabled kernel spinlock_t is mapped to a separate implementation based on rt_mutex which changes the semantics: - - Preemption is not disabled + - Preemption is not disabled. - The hard interrupt related suffixes for spin_lock / spin_unlock - operations (_irq, _irqsave / _irqrestore) do not affect the CPUs - interrupt disabled state + operations (_irq, _irqsave / _irqrestore) do not affect the CPU's + interrupt disabled state. - The soft interrupt related suffix (_bh()) still disables softirq handlers. @@ -279,7 +279,7 @@ fully preemptible context. Instead, use spin_lock_irqsave() and their unlock counterparts. In cases where the interrupt disabling and locking must remain separate, PREEMPT_RT offers a local_lock mechanism. Acquiring the local_lock pins the task to a CPU, -allowing things like per-CPU irq-disabled locks to be acquired. However, +allowing things like per-CPU IRQ-disabled locks to be acquired. However, this approach should be used only where absolutely necessary.