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_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 39CEFC0044D for ; Wed, 11 Mar 2020 22:21:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3AAC120751 for ; Wed, 11 Mar 2020 22:21:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730094AbgCKWVV (ORCPT ); Wed, 11 Mar 2020 18:21:21 -0400 Received: from mout.kundenserver.de ([212.227.126.131]:50763 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729506AbgCKWVU (ORCPT ); Wed, 11 Mar 2020 18:21:20 -0400 Received: from mail-qk1-f170.google.com ([209.85.222.170]) by mrelayeu.kundenserver.de (mreue009 [212.227.15.129]) with ESMTPSA (Nemesis) id 1MfYHQ-1jniWk46VU-00g00q; Wed, 11 Mar 2020 23:21:19 +0100 Received: by mail-qk1-f170.google.com with SMTP id f3so3803357qkh.1; Wed, 11 Mar 2020 15:21:18 -0700 (PDT) X-Gm-Message-State: ANhLgQ1NrVE1szSl2hCxhmSdG53rWyaQCTZZHUSFzuAvOX7qz9FlmnF+ FKpe+9KgM7wU5O4JEd9eVVyBlyY95z4mRI9ndsM= X-Google-Smtp-Source: ADFU+vtUX6596ckwbsQtKLPYKkjWdRNNv2OExbN7pWVykWRKgnRWddSMydtufZDaxYnGmzl5giJGitq9nSLOAiz/v+U= X-Received: by 2002:a37:8707:: with SMTP id j7mr2513764qkd.394.1583965277788; Wed, 11 Mar 2020 15:21:17 -0700 (PDT) MIME-Version: 1.0 References: <671b05bc-7237-7422-3ece-f1a4a3652c92@oracle.com> <7c4c1459-60d5-24c8-6eb9-da299ead99ea@oracle.com> <20200306203439.peytghdqragjfhdx@kahuna> <20200309155945.GA4124965@arrakis.emea.arm.com> <20200309160919.GM25745@shell.armlinux.org.uk> <20200311142905.GI3216816@arrakis.emea.arm.com> <20200311172631.GN3216816@arrakis.emea.arm.com> In-Reply-To: <20200311172631.GN3216816@arrakis.emea.arm.com> From: Arnd Bergmann Date: Wed, 11 Mar 2020 23:21:01 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU To: Catalin Marinas Cc: Russell King - ARM Linux admin , Nishanth Menon , Santosh Shilimkar , Tero Kristo , Linux ARM , Michal Hocko , Rik van Riel , Santosh Shilimkar , Dave Chinner , Linux Kernel Mailing List , Linux-MM , Yafang Shao , Al Viro , Johannes Weiner , linux-fsdevel , kernel-team@fb.com, Kishon Vijay Abraham I , Linus Torvalds , Andrew Morton , Roman Gushchin Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:Y0fVglcNi3gC72aK5fXtxypkAayJT+12w8tKLgShmO81/UTcoGJ NdV/92mYk8imJkqroooPsdEHiKdRRN6F6UWDDjRr8+bYhc5r4TIZ8WmnatiYiN/Kg5yr1M/ UbHjNq/hbtQbj/6+qkvyNKI17QCXz12qQ+d9JGjmlQin9Ezop/VL7stF0tRA2/xPKpmofuX M5f18TPitTjgFno3DmrZQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:sKJPphkq4EU=:s0gkVx3Zr91ZibRaHVQ6T/ Bx8qEqbhocegEone2+WgCDYZxhn76WohWqU0SDLTtKHCR43POf57Tf3V3ZG5qvdShaZH2saWT 9c/h9McjfTbNrnwr7DEjlVE3/R0c97BQkA8TLFDnZYbYP268BHe9Kg8OZlHcsVdD4d6+TAUCs xf8OWwH9BdY/cbBSp+zrturUtr2K35c76uOVGPACWaf4xPjCRI9BnzvxobPiP7UP2w659Q+sC 7FdYkx0UPJTgeoeoREOBKODGMXQunqlZJqgTkrEXquJAQTdKNEB83gbf9Hcgwjhyppy4/tqa3 akkuLAOvHM3GcRco3ahM3Le3IAcA3vWLUGMxt7bCqp/os1B7KNZ5YZLOgXiaaDwhFEn/Gw4zv XM113yRMdhImu3iDti7OfwGUa05JZYAy9Nll1mwi1MsnjOWf+k6erTmQ62Gfm6K19N6x4BM97 i6DOpdVI5fGlypTbHVF49Qbi2rBcTx5UI/U4mUj0vcp3mAze9bOcHeGnXqzEwHAlGtv+VxIel DWp0mwQBglh5NPtiNazlec1dBFHNx9ssGPbMkqr92HLp4EA3+/jVl6EKnMzEHemFmO+3pVyZJ 3+y0wXpOp/8hgUhHqOXUTq28EP6996iCf+NzM2d1qEHIyt3na19BBl9bpCtNRHhb5hLlZkgja YK0MvMJwRmZ7osBuNW55IRjuX8adIzLY/hKRhX9hFNI7c+thIT7q1uToHb0tQi/3HSlti/xQf huMxHQy/crOq5HKWWAar/Sc6wAEN+v1C0y3+FjA+2EYT2dFD4wZrU1WDUmd+gLe/Uv7Q6NQY3 UwHZ2s00xnp47xalH6ACgrI14db+S11O2zzm/D9pic+xBS6wwQ= Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 11, 2020 at 6:26 PM Catalin Marinas wrote: > On Wed, Mar 11, 2020 at 05:59:53PM +0100, Arnd Bergmann wrote: > > On Wed, Mar 11, 2020 at 3:29 PM Catalin Marinas wrote: > > Do you have an estimate of how long writing to TTBR0_64 takes on Cortex-A7 > > and A15, respectively? > > I don't have numbers but it's usually not cheap since you need an ISB to > synchronise the context after TTBR0 update (basically flushing the > pipeline). Ok. > > Another way might be to use a use a temporary buffer that is already > > mapped, and add a memcpy() through L1-cache to reduce the number > > of ttbr0 changes. The buffer would probably have to be on the stack, > > which limits the size, but for large copies get_user_pages()+memcpy() > > may end up being faster anyway. > > IIRC, the x86 attempt from Ingo some years ago was using > get_user_pages() for uaccess. Depending on the size of the buffer, this > may be faster than copying twice. I guess the tradeoffs for that were rather different, as x86 back then had no ASIDs, so changing the page tables required a full TLB flush. Arnd 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_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 473F0C4CECE for ; Wed, 11 Mar 2020 22:21:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3B5112074F for ; Wed, 11 Mar 2020 22:21:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B5112074F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arndb.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CFB8D6B0005; Wed, 11 Mar 2020 18:21:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CAC626B0006; Wed, 11 Mar 2020 18:21:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BC1266B0007; Wed, 11 Mar 2020 18:21:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0229.hostedemail.com [216.40.44.229]) by kanga.kvack.org (Postfix) with ESMTP id A24976B0005 for ; Wed, 11 Mar 2020 18:21:21 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 69A27611D for ; Wed, 11 Mar 2020 22:21:21 +0000 (UTC) X-FDA: 76584503562.22.day07_28dea185d3957 X-HE-Tag: day07_28dea185d3957 X-Filterd-Recvd-Size: 5297 Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.134]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Wed, 11 Mar 2020 22:21:20 +0000 (UTC) Received: from mail-qk1-f174.google.com ([209.85.222.174]) by mrelayeu.kundenserver.de (mreue012 [212.227.15.129]) with ESMTPSA (Nemesis) id 1MsaeR-1jRuWS0rnP-00u2z2 for ; Wed, 11 Mar 2020 23:21:19 +0100 Received: by mail-qk1-f174.google.com with SMTP id u25so3799729qkk.3 for ; Wed, 11 Mar 2020 15:21:18 -0700 (PDT) X-Gm-Message-State: ANhLgQ0W04lZxyclSv5CvzKKDDtMFlUTdOBr3H1xtFlE6O6g5LAJ6+lD 8Uz1DY5WfNsNIfN+w94PX4/r9XF1kHnUb3peuY0= X-Google-Smtp-Source: ADFU+vtUX6596ckwbsQtKLPYKkjWdRNNv2OExbN7pWVykWRKgnRWddSMydtufZDaxYnGmzl5giJGitq9nSLOAiz/v+U= X-Received: by 2002:a37:8707:: with SMTP id j7mr2513764qkd.394.1583965277788; Wed, 11 Mar 2020 15:21:17 -0700 (PDT) MIME-Version: 1.0 References: <671b05bc-7237-7422-3ece-f1a4a3652c92@oracle.com> <7c4c1459-60d5-24c8-6eb9-da299ead99ea@oracle.com> <20200306203439.peytghdqragjfhdx@kahuna> <20200309155945.GA4124965@arrakis.emea.arm.com> <20200309160919.GM25745@shell.armlinux.org.uk> <20200311142905.GI3216816@arrakis.emea.arm.com> <20200311172631.GN3216816@arrakis.emea.arm.com> In-Reply-To: <20200311172631.GN3216816@arrakis.emea.arm.com> From: Arnd Bergmann Date: Wed, 11 Mar 2020 23:21:01 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU To: Catalin Marinas Cc: Russell King - ARM Linux admin , Nishanth Menon , Santosh Shilimkar , Tero Kristo , Linux ARM , Michal Hocko , Rik van Riel , Santosh Shilimkar , Dave Chinner , Linux Kernel Mailing List , Linux-MM , Yafang Shao , Al Viro , Johannes Weiner , linux-fsdevel , kernel-team@fb.com, Kishon Vijay Abraham I , Linus Torvalds , Andrew Morton , Roman Gushchin Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:uoEdR+hxEdtR+T+R2S18ahIeHsR/QZpT2BOseJgsEps9FSUlctq 3Ugmxu3zpO2tLd71tjd2MnUMvJ5V9YNGRHGohG+KdhnBvcfYgh8jeVL2XbPHtte2leobZvX 84ymI8bxsmhMGjHKmEqIPPHuJi+RWfGbhfwcRN34IrOQ5qlHSZkFnI5eERxoGKKeehZSVib u4E3Yq0drZT/2HCZ0M8BQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:e1InS7QJpkg=:zUkOgeqntQpi/RZh0maYwn fR/XZ+z0llME8GLaCnp0JTn8LhZwXCpfYgl8fO1+U9iZJTDfdF7LeTR9vF7P7230fjh+mwrHR Sslqeh6Zu9MoycLm0MjmzmjJt8uBkeU8GAr8D1rUmzMCIbcrBN/IddlKP4T/XrsleBjPrxf/k eXNUUcLRlaGYDuxpdyyon3kTh1sOGUk+d9QF/swIPEV7ogwJjcHkcYVAhw8S7Dc9Ba6wzy+7R irVjBOcpN/FLvcKD2s0N56IDz03RVXDZAUDW08OjTMlX4UnwMRXyLHc1iKlZnobZqEGTvUmGp uHmlNdLMkl9Q48osjQ5EUrLqNcstONJDs5pb1vweMljlEG+feFAV8/dnLzKqJrscaRjp5wOU4 zGsAszvzYikqJlzUBh1GdILqp/zHtgi32/fi/G6bnPKpy4KyAukb9r7/ys7vfv2P+nCQKf2DB Hnln5NiCaWNkLa0HeuRlUmxi2P2mTk3bd7yzAKzrxrfB+wTRGocWRR/hF5yOn2Ul0wiMmBAl9 xqiQ2VGdYNlcS4JkK2/QZuyZPf+uRid4LmEh9QM6soZAx0QOHFPhrPrU38+KQxlAk2mriyS82 co5QAfbkX3CYISC87TSRP3phbPsFNYyzhz+1sFloppjHAVoXPKhGuUP6mCR1hLyZG6PZpXwgF I7/uKNjXCBV0gxIHpsH+FgatipwbM4ypBVluJZi/1KgEoUchv3Su53j6pYXZucdNWvIMtfOFs agk2YqxuG+rILTRBoXJ13wWoqwTCvOMvmsGhHAfv/jMPZBuTLIv4v9fwf5xhC/d/YfX2kJ6oX SXsJFPgmWiGlIM946MSFUQIWNDvkMggvDKmf/dbTLfAqRMPfYA= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Mar 11, 2020 at 6:26 PM Catalin Marinas wrote: > On Wed, Mar 11, 2020 at 05:59:53PM +0100, Arnd Bergmann wrote: > > On Wed, Mar 11, 2020 at 3:29 PM Catalin Marinas wrote: > > Do you have an estimate of how long writing to TTBR0_64 takes on Cortex-A7 > > and A15, respectively? > > I don't have numbers but it's usually not cheap since you need an ISB to > synchronise the context after TTBR0 update (basically flushing the > pipeline). Ok. > > Another way might be to use a use a temporary buffer that is already > > mapped, and add a memcpy() through L1-cache to reduce the number > > of ttbr0 changes. The buffer would probably have to be on the stack, > > which limits the size, but for large copies get_user_pages()+memcpy() > > may end up being faster anyway. > > IIRC, the x86 attempt from Ingo some years ago was using > get_user_pages() for uaccess. Depending on the size of the buffer, this > may be faster than copying twice. I guess the tradeoffs for that were rather different, as x86 back then had no ASIDs, so changing the page tables required a full TLB flush. Arnd 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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 89AACC2BAEE for ; Wed, 11 Mar 2020 22:21:25 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 80C612074F for ; Wed, 11 Mar 2020 22:21:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="JhYVTZDz" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 80C612074F Authentication-Results: mail.kernel.org; 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Wed, 11 Mar 2020 15:21:17 -0700 (PDT) MIME-Version: 1.0 References: <671b05bc-7237-7422-3ece-f1a4a3652c92@oracle.com> <7c4c1459-60d5-24c8-6eb9-da299ead99ea@oracle.com> <20200306203439.peytghdqragjfhdx@kahuna> <20200309155945.GA4124965@arrakis.emea.arm.com> <20200309160919.GM25745@shell.armlinux.org.uk> <20200311142905.GI3216816@arrakis.emea.arm.com> <20200311172631.GN3216816@arrakis.emea.arm.com> In-Reply-To: <20200311172631.GN3216816@arrakis.emea.arm.com> From: Arnd Bergmann Date: Wed, 11 Mar 2020 23:21:01 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] vfs: keep inodes with page cache off the inode shrinker LRU To: Catalin Marinas X-Provags-ID: V03:K1:qKd8/YRt3ysap/A6UAIo8juxn3YF4vWmhlyQwULsOgJyKwVcVME yu3Hxi8gAHiN2neBd02Oe/QL5+m4nXnN4YPaV4saAezYNlNAdSuGsVSakcop7JNsoBbBCop EwPx6pX8swfk8kHLGl+i5vQJ2j6sA77zWUwtWCS3RUCSJDqIcWuuQYuAT+syx2KGWx7o+gE REUmjmo1UKL0qjCBszxrQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:W/QeN4t1laU=:JHPB5skF3/Ixl4gIqMMwGg HuUQDBCM2E8c7RwwNRo/iI3Zr9YFEsdL5qmEgVAB0G+2KXy4+uAXGZHgnbfT+slEOEqRAbWPv BJgLcokl5uw9bZAN6JpaWUIeLvYl9ti6jeK0PC1xe0KHtO8velFJxLm8csQNof84veakh1BVR +VkMDyHUTNkUDJ0quvI8Tg4lKlO9ycKNmZLC8j6OLiUxO6O41dHJBieNdMwWorQX6s7y89OS8 aZ5bF7CMyeZgO65RQBLZg8h55i7gqnGalEc3Frirh1JB9fGtvwFfptkzMzBKsWeTakmAIDRtj yDQTY6CsNOH3eEe0pWIw6Uohs6N7naxg7ME9tul21E/7QWnOc6vLN/EitoG3TOmt8ei3QT1qY tS162KUg71tl0agB+9Txi/Wwy7+G/DvN4jfH69Hrv/Mh8zJjWLwSslrP/azZTTkjxH5vjvMgT oNs5/DwZAzvWHYGYQ55bDJkiBfgQvYApka1copGwehqJSKrMWv/QxVSxwb5iNKeX4grOcBlaB SSNZtWq8yNbs26VEWK1DSrxOfTu3kZxaqhC4kNN21NtDiDkc8mxlYQByY+DYm58761I2Ey9ea U9nbWc3djdfazw7TlQcExwzwqnA1WmVAb0y2BTafpr+KdE8i0s2IgluZ0/zXuPle8je4WeYiO 9l4AAnq4ZIA+Aza4Cbf+8aHWc8XpbKtO8cy7sEzH54gIlTfBikO2cmJPHWVDDif8NpxkLZAPe PozS3wKSYuUbxgZOhGkpEvLF3ZC90S2/4ib+7/AcXf5asbg89+yZOghRPoGwlMJrKQqV34P/Z T2J1JW2fXm2LFDNwRvhtpf8v87i965TmLZgCr/dBxj7oBFQnbs= X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200311_152121_596861_EF744FA6 X-CRM114-Status: GOOD ( 15.78 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nishanth Menon , Michal Hocko , Johannes Weiner , Rik van Riel , Roman Gushchin , Santosh Shilimkar , Dave Chinner , Russell King - ARM Linux admin , Linux Kernel Mailing List , Tero Kristo , Linux-MM , Yafang Shao , Al Viro , Santosh Shilimkar , linux-fsdevel , kernel-team@fb.com, Kishon Vijay Abraham I , Linus Torvalds , Andrew Morton , Linux ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Mar 11, 2020 at 6:26 PM Catalin Marinas wrote: > On Wed, Mar 11, 2020 at 05:59:53PM +0100, Arnd Bergmann wrote: > > On Wed, Mar 11, 2020 at 3:29 PM Catalin Marinas wrote: > > Do you have an estimate of how long writing to TTBR0_64 takes on Cortex-A7 > > and A15, respectively? > > I don't have numbers but it's usually not cheap since you need an ISB to > synchronise the context after TTBR0 update (basically flushing the > pipeline). Ok. > > Another way might be to use a use a temporary buffer that is already > > mapped, and add a memcpy() through L1-cache to reduce the number > > of ttbr0 changes. The buffer would probably have to be on the stack, > > which limits the size, but for large copies get_user_pages()+memcpy() > > may end up being faster anyway. > > IIRC, the x86 attempt from Ingo some years ago was using > get_user_pages() for uaccess. Depending on the size of the buffer, this > may be faster than copying twice. I guess the tradeoffs for that were rather different, as x86 back then had no ASIDs, so changing the page tables required a full TLB flush. Arnd _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel