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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 B54C0C32751 for ; Wed, 31 Jul 2019 06:05:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 969E9208E4 for ; Wed, 31 Jul 2019 06:05:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726582AbfGaGFd (ORCPT ); Wed, 31 Jul 2019 02:05:33 -0400 Received: from relay11.mail.gandi.net ([217.70.178.231]:47827 "EHLO relay11.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725209AbfGaGFd (ORCPT ); Wed, 31 Jul 2019 02:05:33 -0400 Received: from [192.168.0.12] (127.19.86.79.rev.sfr.net [79.86.19.127]) (Authenticated sender: alex@ghiti.fr) by relay11.mail.gandi.net (Postfix) with ESMTPSA id 68D61100008; Wed, 31 Jul 2019 06:05:23 +0000 (UTC) Subject: Re: [PATCH v5 14/14] riscv: Make mmap allocation top-down by default To: Andrew Morton Cc: Luis Chamberlain , Christoph Hellwig , Russell King , Catalin Marinas , Will Deacon , Ralf Baechle , Paul Burton , James Hogan , Palmer Dabbelt , Albert Ou , Alexander Viro , Kees Cook , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, linux-riscv@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org References: <20190730055113.23635-1-alex@ghiti.fr> <20190730055113.23635-15-alex@ghiti.fr> From: Alex Ghiti Message-ID: <88a9bbf8-872f-97cc-fc1a-83eb7694478f@ghiti.fr> Date: Wed, 31 Jul 2019 02:05:23 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190730055113.23635-15-alex@ghiti.fr> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Content-Language: sv-FI Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org On 7/30/19 1:51 AM, Alexandre Ghiti wrote: > In order to avoid wasting user address space by using bottom-up mmap > allocation scheme, prefer top-down scheme when possible. > > Before: > root@qemuriscv64:~# cat /proc/self/maps > 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils > 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils > 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils > 00018000-00039000 rw-p 00000000 00:00 0 [heap] > 1555556000-155556d000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so > 155556d000-155556e000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so > 155556e000-155556f000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so > 155556f000-1555570000 rw-p 00000000 00:00 0 > 1555570000-1555572000 r-xp 00000000 00:00 0 [vdso] > 1555574000-1555576000 rw-p 00000000 00:00 0 > 1555576000-1555674000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so > 1555674000-1555678000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so > 1555678000-155567a000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so > 155567a000-15556a0000 rw-p 00000000 00:00 0 > 3fffb90000-3fffbb1000 rw-p 00000000 00:00 0 [stack] > > After: > root@qemuriscv64:~# cat /proc/self/maps > 00010000-00016000 r-xp 00000000 fe:00 6389 /bin/cat.coreutils > 00016000-00017000 r--p 00005000 fe:00 6389 /bin/cat.coreutils > 00017000-00018000 rw-p 00006000 fe:00 6389 /bin/cat.coreutils > 2de81000-2dea2000 rw-p 00000000 00:00 0 [heap] > 3ff7eb6000-3ff7ed8000 rw-p 00000000 00:00 0 > 3ff7ed8000-3ff7fd6000 r-xp 00000000 fe:00 7187 /lib/libc-2.28.so > 3ff7fd6000-3ff7fda000 r--p 000fd000 fe:00 7187 /lib/libc-2.28.so > 3ff7fda000-3ff7fdc000 rw-p 00101000 fe:00 7187 /lib/libc-2.28.so > 3ff7fdc000-3ff7fe2000 rw-p 00000000 00:00 0 > 3ff7fe4000-3ff7fe6000 r-xp 00000000 00:00 0 [vdso] > 3ff7fe6000-3ff7ffd000 r-xp 00000000 fe:00 7193 /lib/ld-2.28.so > 3ff7ffd000-3ff7ffe000 r--p 00016000 fe:00 7193 /lib/ld-2.28.so > 3ff7ffe000-3ff7fff000 rw-p 00017000 fe:00 7193 /lib/ld-2.28.so > 3ff7fff000-3ff8000000 rw-p 00000000 00:00 0 > 3fff888000-3fff8a9000 rw-p 00000000 00:00 0 [stack] > > Signed-off-by: Alexandre Ghiti > Reviewed-by: Christoph Hellwig > Reviewed-by: Kees Cook > Reviewed-by: Luis Chamberlain > --- > arch/riscv/Kconfig | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 8ef64fe2c2b3..8d0d8af1a744 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -54,6 +54,19 @@ config RISCV > select EDAC_SUPPORT > select ARCH_HAS_GIGANTIC_PAGE > select ARCH_WANT_HUGE_PMD_SHARE if 64BIT > + select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU > + select HAVE_ARCH_MMAP_RND_BITS > + > +config ARCH_MMAP_RND_BITS_MIN > + default 18 if 64BIT > + default 8 > + > +# max bits determined by the following formula: > +# VA_BITS - PAGE_SHIFT - 3 > +config ARCH_MMAP_RND_BITS_MAX > + default 33 if RISCV_VM_SV48 > + default 24 if RISCV_VM_SV39 > + default 17 if RISCV_VM_SV32 > > config MMU > def_bool y Hi Andrew, I have just seen you took this series into mmotm but without Paul's patch ("riscv: kbuild: add virtual memory system selection") on which this commit relies, I'm not sure it could compile without it as there is no default for ARCH_MMAP_RND_BITS_MAX. Thanks, Alex