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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 82B53C6787C for ; Fri, 12 Oct 2018 18:04:22 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DD4152087D for ; Fri, 12 Oct 2018 18:04:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DD4152087D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 42WwhM2KdtzF3TC for ; Sat, 13 Oct 2018 05:04:19 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=davemloft.net Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=davemloft.net (client-ip=2620:137:e000::1:9; helo=shards.monkeyblade.net; envelope-from=davem@davemloft.net; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=davemloft.net Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 42WwfG3l0PzF3Kp for ; Sat, 13 Oct 2018 05:02:29 +1100 (AEDT) Received: from localhost (c-67-183-145-105.hsd1.wa.comcast.net [67.183.145.105]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 45BE6133E9F9A; Fri, 12 Oct 2018 11:02:21 -0700 (PDT) Date: Fri, 12 Oct 2018 11:02:20 -0700 (PDT) Message-Id: <20181012.110220.321284613911888246.davem@davemloft.net> To: kirill@shutemov.name Subject: Re: [PATCH v2 2/2] mm: speed up mremap by 500x on large regions From: David Miller In-Reply-To: <20181012113056.gxhcbrqyu7k7xnyv@kshutemo-mobl1> References: <20181012013756.11285-1-joel@joelfernandes.org> <20181012013756.11285-2-joel@joelfernandes.org> <20181012113056.gxhcbrqyu7k7xnyv@kshutemo-mobl1> X-Mailer: Mew version 6.7 on Emacs 26 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Fri, 12 Oct 2018 11:02:23 -0700 (PDT) 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-mips@linux-mips.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, peterz@infradead.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, mhocko@kernel.org, linux-mm@kvack.org, lokeshgidra@google.com, joel@joelfernandes.org, linux-riscv@lists.infradead.org, elfring@users.sourceforge.net, jonas@southpole.se, linux-s390@vger.kernel.org, dancol@google.com, linux-xtensa@linux-xtensa.org, linux-hexagon@vger.kernel.org, deller@gmx.de, hughd@google.com, jejb@parisc-linux.org, kasan-dev@googlegroups.com, kvmarm@lists.cs.columbia.edu, mingo@redhat.com, geert@linux-m68k.org, aryabinin@virtuozzo.com, linux-snps-arc@lists.infradead.org, kernel-team@android.com, fenghua.yu@intel.com, jdike@addtoit.com, linux-um@lists.infradead.org, Julia.Lawall@lip6.fr, linux-m68k@lists.linux-m68k.org, openrisc@lists.librecores.org, bp@alien8.de, luto@kernel.org, nios2-dev@lists.rocketboards.org, gxt@pku.edu.cn, linux-arm-kernel@lists.infradead.org, chris@zankel.net, richard@nod.at, linux-parisc@vger.kernel.org, pantin@google.com, jcmvbkbc@gmail.com, linux-kernel@vger.kernel.org, minchan@kernel.org, linux-alpha@vger.kernel.org, lftan@altera.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" From: "Kirill A. Shutemov" Date: Fri, 12 Oct 2018 14:30:56 +0300 > I looked into the code more and noticed move_pte() helper called from > move_ptes(). It changes PTE entry to suite new address. > > It is only defined in non-trivial way on Sparc. I don't know much about > Sparc and it's hard for me to say if the optimization will break anything > there. > > I think it worth to disable the optimization if __HAVE_ARCH_MOVE_PTE is > defined. Or make architectures state explicitely that the optimization is > safe. What sparc is doing in move_pte() is flushing the data-cache (synchronously) if the virtual address color of the mapping changes. Hope this helps.