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=-6.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 55C0BC433E1 for ; Fri, 26 Jun 2020 17:34:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 36935206DD for ; Fri, 26 Jun 2020 17:34:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727079AbgFZRe1 (ORCPT ); Fri, 26 Jun 2020 13:34:27 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:56028 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726789AbgFZReS (ORCPT ); Fri, 26 Jun 2020 13:34:18 -0400 Received: from 89-64-83-223.dynamic.chello.pl (89.64.83.223) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.415) id aea2085616e28395; Fri, 26 Jun 2020 19:34:16 +0200 From: "Rafael J. Wysocki" To: Dan Williams , Erik Kaneda Cc: rafael.j.wysocki@intel.com, Len Brown , Borislav Petkov , Ira Weiny , James Morse , Myron Stowe , Andy Shevchenko , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-nvdimm@lists.01.org, Bob Moore Subject: [RFT][PATCH v3 0/4] ACPI: ACPICA / OSL: Avoid unmapping ACPI memory inside of the AML interpreter Date: Fri, 26 Jun 2020 19:28:27 +0200 Message-ID: <2788992.3K7huLjdjL@kreacher> In-Reply-To: <2713141.s8EVnczdoM@kreacher> References: <158889473309.2292982.18007035454673387731.stgit@dwillia2-desk3.amr.corp.intel.com> <2713141.s8EVnczdoM@kreacher> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi All, On Monday, June 22, 2020 3:50:42 PM CEST Rafael J. Wysocki wrote: > Hi All, > > This series is to address the problem with RCU synchronization occurring, > possibly relatively often, inside of acpi_ex_system_memory_space_handler(), > when the namespace and interpreter mutexes are held. > > Like I said before, I had decided to change the approach used in the previous > iteration of this series and to allow the unmap operations carried out by > acpi_ex_system_memory_space_handler() to be deferred in the first place, > which is done in patches [1-2/4]. In the meantime I realized that calling syncrhonize_rcu_expedited() under the "tables" mutex within ACPICA is not quite a good idea too and that there is no reason for any users of acpi_os_unmap_memory() in the tree to use the "sync" variant of unmapping. So, unless I'm missing something, acpi_os_unmap_memory() can be changed to always defer the final unmapping and the only ACPICA change needed to support that is the addition of the acpi_os_release_unused_mappings() call to get rid of the unused mappings when leaving the interpreter (module the extra call in the debug code for consistency). So patches [1-2/4] have been changed accordingly. > However, it turns out that the "fast-path" mapping is still useful on top of > the above to reduce the number of ioremap-iounmap cycles for the same address > range and so it is introduced by patches [3-4/4]. Patches [3-4/4] still do what they did, but they have been simplified a bit after rebasing on top of the new [1-2/4]. The below information is still valid, but it applies to the v3, of course. > For details, please refer to the patch changelogs. > > The series is available from the git branch at > > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git \ > acpica-osl > > for easier testing. Also the series have been tested locally. Thanks, Rafael