From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-f198.google.com (mail-oi1-f198.google.com [209.85.167.198]) by kanga.kvack.org (Postfix) with ESMTP id 143DA6B036B for ; Mon, 29 Oct 2018 06:28:36 -0400 (EDT) Received: by mail-oi1-f198.google.com with SMTP id w124-v6so2306822oiw.15 for ; Mon, 29 Oct 2018 03:28:36 -0700 (PDT) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id y203-v6si9256156oie.8.2018.10.29.03.28.34 for ; Mon, 29 Oct 2018 03:28:34 -0700 (PDT) Date: Mon, 29 Oct 2018 10:28:40 +0000 From: Will Deacon Subject: Re: [PATCH 2/4] mm: speed up mremap by 500x on large regions (v2) Message-ID: <20181029102840.GC13965@arm.com> References: <20181013013200.206928-1-joel@joelfernandes.org> <20181013013200.206928-3-joel@joelfernandes.org> <20181024101255.it4lptrjogalxbey@kshutemo-mobl1> <20181024115733.GN8537@350D> <20181024125724.yf6frdimjulf35do@kshutemo-mobl1> <20181025020907.GA13560@joelaf.mtv.corp.google.com> <20181025101900.phqnqpoju5t2gar5@kshutemo-mobl1> <20181026211148.GA140716@joelaf.mtv.corp.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181026211148.GA140716@joelaf.mtv.corp.google.com> Sender: owner-linux-mm@kvack.org List-ID: To: Joel Fernandes Cc: "Kirill A. Shutemov" , Balbir Singh , linux-kernel@vger.kernel.org, kernel-team@android.com, minchan@kernel.org, pantin@google.com, hughd@google.com, lokeshgidra@google.com, dancol@google.com, mhocko@kernel.org, akpm@linux-foundation.org, Andrey Ryabinin , Andy Lutomirski , anton.ivanov@kot-begemot.co.uk, Borislav Petkov , Catalin Marinas , Chris Zankel , Dave Hansen , "David S. Miller" , elfring@users.sourceforge.net, Fenghua Yu , Geert Uytterhoeven , Guan Xuetao , Helge Deller , Ingo Molnar , "James E.J. Bottomley" , Jeff Dike , Jonas Bonn , Julia Lawall , kasan-dev@googlegroups.com, kvmarm@lists.cs.columbia.edu, Ley Foon Tan , linux-alpha@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-ia64@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@linux-mips.org, linux-mm@kvack.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, Max Filippov , nios2-dev@lists.rocketboards.org, Peter Zijlstra , Richard Weinberger , Rich Felker , Sam Creasey , sparclinux@vger.kernel.org, Stafford Horne , Stefan Kristiansson , Thomas Gleixner , Tony Luck , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Yoshinori Sato On Fri, Oct 26, 2018 at 02:11:48PM -0700, Joel Fernandes wrote: > My thinking is to take it slow and get the patch in in its current state, > since it improves x86. Then as a next step, look into why the arm64 tlb > flushes are that expensive and look into optimizing that. On arm64 I am > testing on a 4.9 kernel so I'm wondering there are any optimizations since > 4.9 that can help speed it up there. After that, if all else fails about > speeding up arm64, then I look into developing the cleanest possible solution > where we can keep the lock held for longer and flush lesser. We rewrote a good chunk of the arm64 TLB invalidation and core mmu_gather code this merge window, so please do have another look at -rc1! Will