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: 11458337 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0AC351668 for ; Wed, 25 Mar 2020 16:58:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEFC620772 for ; Wed, 25 Mar 2020 16:58:33 +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="Ny0TO9lE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727729AbgCYQ63 (ORCPT ); Wed, 25 Mar 2020 12:58:29 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:47796 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726102AbgCYQ63 (ORCPT ); Wed, 25 Mar 2020 12:58:29 -0400 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 Cc: LKML , Peter Zijlstra , Ingo Molnar , Sebastian Siewior , Linus Torvalds , Joel Fernandes , Oleg Nesterov , Davidlohr Bueso , Jonathan Corbet , Logan Gunthorpe , Bjorn Helgaas , Kurt Schwemmer , linux-pci@vger.kernel.org, Greg Kroah-Hartman , Felipe Balbi , linux-usb@vger.kernel.org, Kalle Valo , "David S. Miller" , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Darren Hart , Andy Shevchenko , platform-driver-x86@vger.kernel.org, Zhang Rui , "Rafael J. Wysocki" , linux-pm@vger.kernel.org, Len Brown , linux-acpi@vger.kernel.org, kbuild test robot , Nick Hu , Greentime Hu , Vincent Chen , Guo Ren , linux-csky@vger.kernel.org, Brian Cain , linux-hexagon@vger.kernel.org, Tony Luck , Fenghua Yu , linux-ia64@vger.kernel.org, Michal Simek , Michael Ellerman , Arnd Bergmann , Geoff Levand , linuxppc-dev@lists.ozlabs.org, Davidlohr Bueso 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 Sender: platform-driver-x86-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: platform-driver-x86@vger.kernel.org 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.