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=-10.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,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 4F701C2BBCA for ; Thu, 17 Dec 2020 17:29:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21BA2238EF for ; Thu, 17 Dec 2020 17:29:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730083AbgLQR3c (ORCPT ); Thu, 17 Dec 2020 12:29:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729330AbgLQR3a (ORCPT ); Thu, 17 Dec 2020 12:29:30 -0500 Received: from mail-oi1-x235.google.com (mail-oi1-x235.google.com [IPv6:2607:f8b0:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D8C2C0617A7; Thu, 17 Dec 2020 09:28:50 -0800 (PST) Received: by mail-oi1-x235.google.com with SMTP id q205so20304773oig.13; Thu, 17 Dec 2020 09:28:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=ZcIxHa95N4LovQ/B6AMqwtAFl8mnRc53Nbirnw11r50=; b=e1p8GzBoQCVqkpBiort9NEDOLtFOG3dNtDOxdQ2A0+4raTADN7kej3w9MvbPP3EZ+i bXoVhFaHvHz8pbA+DnMxFEm6ISRTnBYCrQTWHslM9wZMgGeSWRz4sKF1MspxFOKmd5N8 zkhxMKzEYG0ieSX7nRK8aP7o1zi3c/mB3Q7JhdLD1PLUTSM/D1r5x9HMGsEE7QdcIAjd hRrd+8stIJqfd+Vn9dOACwgruNSQ7G9fAqxho+VDZqVTfmPuWF4bOwbZnKpg/kCc/Qu+ CNbFW7TES4ofZB5b4bHs55YAeFcgyksMOXjTzG1GrU4R5ujqZ+g1+nWhWqaW2maAXq+o P4gw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=ZcIxHa95N4LovQ/B6AMqwtAFl8mnRc53Nbirnw11r50=; b=Q4iTeGC0JXrXPyxHo0OzE3ihFT0VXom8gZk079ON7EGuQElGfvOHKo/XNa+WGular2 /rMnxvBKkaqf54ybMQlfbht7CU5c8JGFt1694dhC0jgB2ZORiTP3j3wYEzUh4SDx6wh3 m7vREXHoKp4YBZcE9D3E5sTC1UKxBCuk99iIqRwc9NrR1lvLrEWIot4wq7DjZEuDR9/x TWF5bYLrAfWMn+NUCDoFG3WSLcHnPemaxkOU08wviuGvUjikZwR1rw9Hs4DRRCs4dTTN bK06v9+9nrBiY+Gc7bo/2CshhoBiwilMqbwTYoPv/hKs827qbZML0pyFexhjwyEabe5g Hxug== X-Gm-Message-State: AOAM533sZFImtgp57NSBROf954xDbMUzZ4Jm5Moohf/mOkM09JU1CGZZ AgPCFYdKG2fuW0eYLei5WDY= X-Google-Smtp-Source: ABdhPJyr+/QwL5NDeUQ8MUQSocj5W+U9Y5UMmShaQ1vbluEM/9IIf1Kq9FhfjsIkohBMfgN3/ffUcw== X-Received: by 2002:aca:3145:: with SMTP id x66mr122419oix.29.1608226129792; Thu, 17 Dec 2020 09:28:49 -0800 (PST) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id n13sm1323497otk.58.2020.12.17.09.28.48 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 17 Dec 2020 09:28:48 -0800 (PST) Sender: Guenter Roeck Date: Thu, 17 Dec 2020 09:28:47 -0800 From: Guenter Roeck To: Kalesh Singh Cc: surenb@google.com, minchan@google.com, joelaf@google.com, lokeshgidra@google.com, kernel-team@android.com, kernel test robot , "Kirill A . Shutemov" , Andrew Morton , Catalin Marinas , Will Deacon , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Shuah Khan , Peter Zijlstra , "Aneesh Kumar K.V" , Kees Cook , Masahiro Yamada , Arnd Bergmann , Sami Tolvanen , Josh Poimboeuf , Frederic Weisbecker , Krzysztof Kozlowski , Hassan Naveed , Christian Brauner , Stephen Boyd , Anshuman Khandual , Gavin Shan , Mike Rapoport , Steven Price , Jia He , John Hubbard , Jason Gunthorpe , Yang Shi , Mina Almasry , Ralph Campbell , Ram Pai , Sandipan Das , Dave Hansen , Brian Geffon , Masami Hiramatsu , Ira Weiny , SeongJae Park , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v4 3/5] mm: Speedup mremap on 1GB or larger regions Message-ID: <20201217172847.GA89104@roeck-us.net> References: <20201014005320.2233162-1-kaleshsingh@google.com> <20201014005320.2233162-4-kaleshsingh@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201014005320.2233162-4-kaleshsingh@google.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 14, 2020 at 12:53:08AM +0000, Kalesh Singh wrote: > Android needs to move large memory regions for garbage collection. > The GC requires moving physical pages of multi-gigabyte heap > using mremap. During this move, the application threads have to > be paused for correctness. It is critical to keep this pause as > short as possible to avoid jitters during user interaction. > > Optimize mremap for >= 1GB-sized regions by moving at the PUD/PGD > level if the source and destination addresses are PUD-aligned. > For CONFIG_PGTABLE_LEVELS == 3, moving at the PUD level in effect moves > PGD entries, since the PUD entry is “folded back” onto the PGD entry. > Add HAVE_MOVE_PUD so that architectures where moving at the PUD level > isn't supported/tested can turn this off by not selecting the config. > > Fix build test error from v1 of this series reported by > kernel test robot in [1]. > > [1] https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/thread/CKPGL4FH4NG7TGH2CVYX2UX76L25BTA3/ > > Signed-off-by: Kalesh Singh > Reported-by: kernel test robot > Acked-by: Kirill A. Shutemov > Cc: Andrew Morton I thought I reported it, but maybe I didn't. This patch causes all 'parisc' qemu emulations to fail. Typical log: Freeing unused kernel memory: 604K Write protected read-only-after-init data: 2k rodata_test: end of .rodata is not page size aligned Run /sbin/init as init process process '/bin/busybox' started with executable stack Failed to execute /sbin/init (error -12) Reverting this patch fixes the problem. Bisect log from linux-next below. The patch (and thus the problem) are now in mainline Linux. Guenter --- # bad: [7bba37a1591369e2e506d599b8f5d7d0516b2dbc] Add linux-next specific files for 20201214 # good: [0477e92881850d44910a7e94fc2c46f96faa131f] Linux 5.10-rc7 git bisect start 'HEAD' 'v5.10-rc7' # good: [fe5c40ab90a1f82ba97294637eaf875cfdd7a05f] Merge remote-tracking branch 'nand/nand/next' git bisect good fe5c40ab90a1f82ba97294637eaf875cfdd7a05f # good: [674a0d6de8bd290671f7dff405205871a70300b3] Merge remote-tracking branch 'spi/for-next' git bisect good 674a0d6de8bd290671f7dff405205871a70300b3 # good: [8623dae312f73a2ea3230b1c648d3004cfc224ce] Merge remote-tracking branch 'vfio/next' git bisect good 8623dae312f73a2ea3230b1c648d3004cfc224ce # good: [dd26635f54bcd8e5d4e875a209f82a0423ba9c08] Merge remote-tracking branch 'gpio/for-next' git bisect good dd26635f54bcd8e5d4e875a209f82a0423ba9c08 # good: [86e9c9a734889fe437442e0a35eb4c61d319cb47] Merge remote-tracking branch 'memblock/for-next' git bisect good 86e9c9a734889fe437442e0a35eb4c61d319cb47 # bad: [3452331fda80b1cb5e121e6718ca6c07264382b2] userfaultfd: add user-mode only option to unprivileged_userfaultfd sysctl knob git bisect bad 3452331fda80b1cb5e121e6718ca6c07264382b2 # bad: [19f468d54fcffc3f98b71e3e12ff23726767d953] mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio git bisect bad 19f468d54fcffc3f98b71e3e12ff23726767d953 # good: [d89f3ababcac54493a4cb0582c61eb5f426b44e3] mm: remove pagevec_lookup_range_nr_tag() git bisect good d89f3ababcac54493a4cb0582c61eb5f426b44e3 # good: [eba8373dcb40d30952f31d5fc0cff56b78f46273] mm/mlock: remove __munlock_isolate_lru_page() git bisect good eba8373dcb40d30952f31d5fc0cff56b78f46273 # good: [8831d3f3564beba0f3f1b5291c88b35725bc45c9] xen/unpopulated-alloc: consolidate pgmap manipulation git bisect good 8831d3f3564beba0f3f1b5291c88b35725bc45c9 # bad: [b8d53d70851821d8a2040ddca3aa6ee88fc8aaec] mm/page_vma_mapped.c: add colon to fix kernel-doc markups error for check_pte git bisect bad b8d53d70851821d8a2040ddca3aa6ee88fc8aaec # bad: [e77846c3da1862faa25c08e186a62b03e98c862f] x86: mremap speedup - Enable HAVE_MOVE_PUD git bisect bad e77846c3da1862faa25c08e186a62b03e98c862f # bad: [72ad8951bac1c559ea1b691a0b035fb339e4d71d] mm: speedup mremap on 1GB or larger regions git bisect bad 72ad8951bac1c559ea1b691a0b035fb339e4d71d # good: [fa94bfe31609787501a1ff8d7659ade5734ec4e5] kselftests: vm: add mremap tests git bisect good fa94bfe31609787501a1ff8d7659ade5734ec4e5 # first bad commit: [72ad8951bac1c559ea1b691a0b035fb339e4d71d] mm: speedup mremap on 1GB or larger regions