From patchwork Sun Apr 14 05:59:12 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 10899695 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6E9E61390 for ; Sun, 14 Apr 2019 05:59:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 04D0128A89 for ; Sun, 14 Apr 2019 05:59:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id ECED528A9D; Sun, 14 Apr 2019 05:59:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4E37A28A8B for ; Sun, 14 Apr 2019 05:59:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 29EAA6B0005; Sun, 14 Apr 2019 01:59:37 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 2283E6B0006; Sun, 14 Apr 2019 01:59:37 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0A2036B0008; Sun, 14 Apr 2019 01:59:37 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id ACF096B0005 for ; Sun, 14 Apr 2019 01:59:36 -0400 (EDT) Received: by mail-ed1-f69.google.com with SMTP id c40so7232722eda.10 for ; Sat, 13 Apr 2019 22:59:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:date:message-id:in-reply-to:references; bh=pXwTSUlqonpPBE1Ovkstllk7lYSjhD8ZYJok0AGWG+E=; b=RHKaWasJ/f+mJXuIzDiV1y7QGS5ct+ZT+4F2NFv27fQ2QS2PCakSwNX2bjgLLDfGqU 5aniQrqpRRodle137wHac7TqiDehnKvzXrSOGC7R/GrPvpcAhIHWTTRHrtxwHjvQMPsV p2uiJaU9bMgmqCU4mGRAQEI6IwBg/u2rkATyaRyswnF7w8MGl5ukJcZ2ioUw5aNIcs+I L8LitnkfxUSWImhBHDc7WpB0XvmBxuE/cfGPzN/uLuZNNRYSgGilvOH+0Sro/LTLy55x 0skmpkt/tK5UM5L7ieA/A5l/KJVNFbHkdGu7rt3p64kShaNtBj9v2cFaStxr+zNuaCnW yfkQ== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com X-Gm-Message-State: APjAAAWTmEXMFK68975htiFSKEN6MuVFwuIKYa4jTTHHwn/WB9cZZR4h Zp46qyW6ej7cOSCcO73UdOz0lD9GoKOAM214+Gp7yuj6J9Eoi2vNbSQLRbXKWNC1rt0iGzDEVVu HOFYpYTR4PVI3O5yh4nQ3tqEiCD4v4HFcSedbGD/DV0lOXqT9RBzW/i8eWNySmnhEwg== X-Received: by 2002:a17:906:1545:: with SMTP id c5mr37195232ejd.135.1555221576100; Sat, 13 Apr 2019 22:59:36 -0700 (PDT) X-Google-Smtp-Source: APXvYqy5rPIdoR0yUNL2B5gWMHMwyEkM6peJeQ5FHTntQ1MM/G72qm79w6z3onobkh5YFgV6aYS/ X-Received: by 2002:a17:906:1545:: with SMTP id c5mr37195192ejd.135.1555221574872; Sat, 13 Apr 2019 22:59:34 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555221574; cv=none; d=google.com; s=arc-20160816; b=nhyrt5iQvzUvHELTOzrIdjeruDmCdpjDztOZZ6vxG8q1rCuORGw/58FfniZm3JZiLL Pdnjepkzuf8CcSBFUgnXHbWREDRQhj+P2XNNwXffUM8ylCRLewR2nZ6e8Ef9/nIhM90S GB291fGITgDfJMsL33pDQz8qjXamZkpsJRqmfllYYObjdte0oIk83c//CHf8hQkIPine 3ohsp51bWxLTtjYnOO2tPKls5glAiJY1dKkv2QLE6zNvS29s8f0AHtTiqzMeXvRgOJUU zQVl1JNBWy0Zc0njnztcoOWm2qCnfsw99WEBXpA+HZ8NJoO7PzKUZL6AlKmoqGK4mP5m p+Wg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from; bh=pXwTSUlqonpPBE1Ovkstllk7lYSjhD8ZYJok0AGWG+E=; b=GGv+Ey4AUa2bXxGeobdOeCtuV9UhYjd8ML9PRMcfe2Jf+ISDBSh/Yuw6+22TthaQz7 hH5P/bka9Sl1x7u86j0WJ1ydA5xS03vx2VVtKoslNZMnzGN3CkpiHD9k9Cv6yPAwPYRc U3znjNsprlA0nNTeNQ7tDMAUx42daIjwmQ78Wpnz+Yp9HdA4DYO6UV7QwvyEEEbgK0OZ IkhtJzhX8H7lTSYPDgU5YEhalgVz/YNJyIOardjrdEg3fo6r4ojk2rtAaYZkUjqUfmJz QofXIs4Sbfsdn0RXpjuuEehNL5dYhdHCBlAbs2efdahWnEhczZvpW2iixpRd2CTZ6Y1n G2fQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id h44si823989ede.156.2019.04.13.22.59.34 for ; Sat, 13 Apr 2019 22:59:34 -0700 (PDT) Received-SPF: pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) client-ip=217.140.101.70; Authentication-Results: mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ABA6015AD; Sat, 13 Apr 2019 22:59:33 -0700 (PDT) Received: from p8cg001049571a15.blr.arm.com (p8cg001049571a15.blr.arm.com [10.162.41.123]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5496E3F557; Sat, 13 Apr 2019 22:59:28 -0700 (PDT) From: Anshuman Khandual To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, akpm@linux-foundation.org, will.deacon@arm.com, catalin.marinas@arm.com Cc: mhocko@suse.com, mgorman@techsingularity.net, james.morse@arm.com, mark.rutland@arm.com, robin.murphy@arm.com, cpandya@codeaurora.org, arunks@codeaurora.org, dan.j.williams@intel.com, osalvador@suse.de, david@redhat.com, cai@lca.pw, logang@deltatee.com, ira.weiny@intel.com Subject: [PATCH V2 1/2] mm/hotplug: Reorder arch_remove_memory() call in __remove_memory() Date: Sun, 14 Apr 2019 11:29:12 +0530 Message-Id: <1555221553-18845-2-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1555221553-18845-1-git-send-email-anshuman.khandual@arm.com> References: <1555221553-18845-1-git-send-email-anshuman.khandual@arm.com> 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: X-Virus-Scanned: ClamAV using ClamSMTP Memory hot remove uses get_nid_for_pfn() while tearing down linked sysfs entries between memory block and node. It first checks pfn validity with pfn_valid_within() before fetching nid. With CONFIG_HOLES_IN_ZONE config (arm64 has this enabled) pfn_valid_within() calls pfn_valid(). pfn_valid() is an arch implementation on arm64 (CONFIG_HAVE_ARCH_PFN_VALID) which scans all mapped memblock regions with memblock_is_map_memory(). This creates a problem in memory hot remove path which has already removed given memory range from memory block with memblock_[remove|free] before arriving at unregister_mem_sect_under_nodes(). Hence get_nid_for_pfn() returns -1 skipping subsequent sysfs_remove_link() calls leaving node <-> memory block sysfs entries as is. Subsequent memory add operation hits BUG_ON() because of existing sysfs entries. [ 62.007176] NUMA: Unknown node for memory at 0x680000000, assuming node 0 [ 62.052517] ------------[ cut here ]------------ [ 62.053211] kernel BUG at mm/memory_hotplug.c:1143! [ 62.053868] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP [ 62.054589] Modules linked in: [ 62.054999] CPU: 19 PID: 3275 Comm: bash Not tainted 5.1.0-rc2-00004-g28cea40b2683 #41 [ 62.056274] Hardware name: linux,dummy-virt (DT) [ 62.057166] pstate: 40400005 (nZcv daif +PAN -UAO) [ 62.058083] pc : add_memory_resource+0x1cc/0x1d8 [ 62.058961] lr : add_memory_resource+0x10c/0x1d8 [ 62.059842] sp : ffff0000168b3ce0 [ 62.060477] x29: ffff0000168b3ce0 x28: ffff8005db546c00 [ 62.061501] x27: 0000000000000000 x26: 0000000000000000 [ 62.062509] x25: ffff0000111ef000 x24: ffff0000111ef5d0 [ 62.063520] x23: 0000000000000000 x22: 00000006bfffffff [ 62.064540] x21: 00000000ffffffef x20: 00000000006c0000 [ 62.065558] x19: 0000000000680000 x18: 0000000000000024 [ 62.066566] x17: 0000000000000000 x16: 0000000000000000 [ 62.067579] x15: ffffffffffffffff x14: ffff8005e412e890 [ 62.068588] x13: ffff8005d6b105d8 x12: 0000000000000000 [ 62.069610] x11: ffff8005d6b10490 x10: 0000000000000040 [ 62.070615] x9 : ffff8005e412e898 x8 : ffff8005e412e890 [ 62.071631] x7 : ffff8005d6b105d8 x6 : ffff8005db546c00 [ 62.072640] x5 : 0000000000000001 x4 : 0000000000000002 [ 62.073654] x3 : ffff8005d7049480 x2 : 0000000000000002 [ 62.074666] x1 : 0000000000000003 x0 : 00000000ffffffef [ 62.075685] Process bash (pid: 3275, stack limit = 0x00000000d754280f) [ 62.076930] Call trace: [ 62.077411] add_memory_resource+0x1cc/0x1d8 [ 62.078227] __add_memory+0x70/0xa8 [ 62.078901] probe_store+0xa4/0xc8 [ 62.079561] dev_attr_store+0x18/0x28 [ 62.080270] sysfs_kf_write+0x40/0x58 [ 62.080992] kernfs_fop_write+0xcc/0x1d8 [ 62.081744] __vfs_write+0x18/0x40 [ 62.082400] vfs_write+0xa4/0x1b0 [ 62.083037] ksys_write+0x5c/0xc0 [ 62.083681] __arm64_sys_write+0x18/0x20 [ 62.084432] el0_svc_handler+0x88/0x100 [ 62.085177] el0_svc+0x8/0xc Re-ordering arch_remove_memory() with memblock_[free|remove] solves the problem on arm64 as pfn_valid() behaves correctly and returns positive as memblock for the address range still exists. arch_remove_memory() removes applicable memory sections from zone with __remove_pages() and tears down kernel linear mapping. Removing memblock regions afterwards is safe because there is no other memblock (bootmem) allocator user that late. So nobody is going to allocate from the removed range just to blow up later. Also nobody should be using the bootmem allocated range else we wouldn't allow to remove it. So reordering is indeed safe. Acked-by: Michal Hocko Reviewed-by: David Hildenbrand Reviewed-by: Oscar Salvador Signed-off-by: Anshuman Khandual --- mm/memory_hotplug.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 0082d69..71d0d79 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1872,11 +1872,10 @@ void __ref __remove_memory(int nid, u64 start, u64 size) /* remove memmap entry */ firmware_map_remove(start, start + size, "System RAM"); + arch_remove_memory(nid, start, size, NULL); memblock_free(start, size); memblock_remove(start, size); - arch_remove_memory(nid, start, size, NULL); - try_offline_node(nid); mem_hotplug_done(); From patchwork Sun Apr 14 05:59:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anshuman Khandual X-Patchwork-Id: 10899699 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id EBA8F1390 for ; Sun, 14 Apr 2019 05:59:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D173027F60 for ; Sun, 14 Apr 2019 05:59:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C4A0D28174; Sun, 14 Apr 2019 05:59:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 87DB8286B3 for ; Sun, 14 Apr 2019 05:59:43 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7F7126B0006; Sun, 14 Apr 2019 01:59:42 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 77F686B0008; Sun, 14 Apr 2019 01:59:42 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5D1876B000A; Sun, 14 Apr 2019 01:59:42 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by kanga.kvack.org (Postfix) with ESMTP id 0C0216B0006 for ; Sun, 14 Apr 2019 01:59:42 -0400 (EDT) Received: by mail-ed1-f72.google.com with SMTP id f42so1976311edd.0 for ; Sat, 13 Apr 2019 22:59:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-original-authentication-results:x-gm-message-state:from:to:cc :subject:date:message-id:in-reply-to:references; bh=xYveJDlNs6Ar5aDVGhX69HkAwPho/6qZ2uHfL5yg948=; b=LwqN+jDlnn88fbSj0dZDiDu57iIfo8pXXkXftsAzAPtI7qnevJfMxFfKWciyQUHDlu 11thh/mdPIqjw13QosAuVUUS5r2EjbM8BvMIhYvmSK4aRGFFXJhtvNcmyMFmk0Rf7MUr 8bX8cpLnvPkd8hwO/EVs37IhsFJhrS8xXKcGONR8Wo4c8qj8AOF0OrdsGhxOBc7/6+SK JZGle3chwW0E/hVS5LQ11l9SJrTCR2Q0acDnzonC1d/VNovAr7+nmc0+cf4aSNsbZ/jl 38NpFGXBOgVn2a5UcVa05GJMcXiCKNyy7jM9L2ugXaz6g76rnfkfdPmAjUFJKxLy4HFI TAig== X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com X-Gm-Message-State: APjAAAXr9KfjE90Vp1GjARmdg7WYqOX+4svII8FauaSwaog6bUiozUx/ TZ9wJwowbNUT0iqLmuIUGqPxV25HWxceYYVmF3jI2IXzrVB0Ka3+7AnK9l1JVwT/pOHkdseF0Nr jq4a84FURJg2qD67xkDuKjbYGLZ7avfPgLaUwdeJ96mHBy3w0JiUOkfILleH3LrZWLA== X-Received: by 2002:a50:85c5:: with SMTP id q5mr25642988edh.110.1555221581536; Sat, 13 Apr 2019 22:59:41 -0700 (PDT) X-Google-Smtp-Source: APXvYqzFH9+GF8R/4yAGJgj7hfxn7hSPYwgIWCnWeAPsWdsy2d7skIsWQm7LRPEvY13iZjP2g2r9 X-Received: by 2002:a50:85c5:: with SMTP id q5mr25642948edh.110.1555221580608; Sat, 13 Apr 2019 22:59:40 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1555221580; cv=none; d=google.com; s=arc-20160816; b=WOlXhpfcRkH0uvDnSrCaBDg02CDMrxSCZmFZBAcRcfi4yUIGT8jq4r0yDNeRMcB2wd nrFPYrM1l6jxxUwXF3/0iZgzDuRI9jy6MZm1jw5zBIuxsiq4gdF0AE/pr9x6GuHlu+5l Gu9LVbV4FRN2lLnPttcOXXqKK9dRBMcwY02II0oDSac3A6KdLuJ/7y0ykfKxRqZCKo6p RFw+sO8RpIKaSrJqcRRuAqOmPRWllFOL2bxr4eABeoffHOeA/h7k0lUg1EkVIhyvKlrn 1QwbWkmL5GyJuGgtoO6mr3hKz4+pXQBX+sWip63q6MjuUnZx32Z2hd5HW+wO751H1SMw ljVA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from; bh=xYveJDlNs6Ar5aDVGhX69HkAwPho/6qZ2uHfL5yg948=; b=yPv8RpOZAIfiGHqmD9uwoNuwOMo4H71gTR3a8rfkF14V4mE4z6TZbT7LFMT+W0XgbE cjfp5tk9sTvmqnGCA8a/otBwJJL9p0mnVv3XMtfIpcBOUS1v1pDi9Xqip5RoKZVxrGNr OrlBKk9imO+5liCmsOGAcRc+BpWMguai3XZeXrJ9eJxLvVaeF42KYu1dFnvVyPuJviqY 8CQwY0ICzRKJtlxtRwn0NJexzAXSYn8Z/OxZRYSg8aVA3tDjtdYA6Xr8Ydl2JB2+E3eI jy+oAd5YKc5q4E3bgJf1WlX0BPtI9iuRn36hL886H2IWoiy/hcAmDch8Dq9jDbeRs4q3 rBcw== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id g9si2321232eje.367.2019.04.13.22.59.40 for ; Sat, 13 Apr 2019 22:59:40 -0700 (PDT) Received-SPF: pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) client-ip=217.140.101.70; Authentication-Results: mx.google.com; spf=pass (google.com: domain of anshuman.khandual@arm.com designates 217.140.101.70 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8110615AD; Sat, 13 Apr 2019 22:59:39 -0700 (PDT) Received: from p8cg001049571a15.blr.arm.com (p8cg001049571a15.blr.arm.com [10.162.41.123]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 2A6343F557; Sat, 13 Apr 2019 22:59:33 -0700 (PDT) From: Anshuman Khandual To: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, akpm@linux-foundation.org, will.deacon@arm.com, catalin.marinas@arm.com Cc: mhocko@suse.com, mgorman@techsingularity.net, james.morse@arm.com, mark.rutland@arm.com, robin.murphy@arm.com, cpandya@codeaurora.org, arunks@codeaurora.org, dan.j.williams@intel.com, osalvador@suse.de, david@redhat.com, cai@lca.pw, logang@deltatee.com, ira.weiny@intel.com Subject: [PATCH V2 2/2] arm64/mm: Enable memory hot remove Date: Sun, 14 Apr 2019 11:29:13 +0530 Message-Id: <1555221553-18845-3-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1555221553-18845-1-git-send-email-anshuman.khandual@arm.com> References: <1555221553-18845-1-git-send-email-anshuman.khandual@arm.com> 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: X-Virus-Scanned: ClamAV using ClamSMTP Memory removal from an arch perspective involves tearing down two different kernel based mappings i.e vmemmap and linear while releasing related page table pages allocated for the physical memory range to be removed. Define a common kernel page table tear down helper remove_pagetable() which can be used to unmap given kernel virtual address range. In effect it can tear down both vmemap or kernel linear mappings. This new helper is called from both vmemamp_free() and ___remove_pgd_mapping() during memory removal. The argument 'direct' here identifies kernel linear mappings. Vmemmap mappings page table pages are allocated through sparse mem helper functions like vmemmap_alloc_block() which does not cycle the pages through pgtable_page_ctor() constructs. Hence while removing it skips corresponding destructor construct pgtable_page_dtor(). While here update arch_add_mempory() to handle __add_pages() failures by just unmapping recently added kernel linear mapping. Now enable memory hot remove on arm64 platforms by default with ARCH_ENABLE_MEMORY_HOTREMOVE. This implementation is overall inspired from kernel page table tear down procedure on X86 architecture. Signed-off-by: Anshuman Khandual --- arch/arm64/Kconfig | 3 + arch/arm64/include/asm/pgtable.h | 2 + arch/arm64/mm/mmu.c | 221 ++++++++++++++++++++++++++++++++++++++- 3 files changed, 224 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index c383625..a870eb2 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -267,6 +267,9 @@ config HAVE_GENERIC_GUP config ARCH_ENABLE_MEMORY_HOTPLUG def_bool y +config ARCH_ENABLE_MEMORY_HOTREMOVE + def_bool y + config SMP def_bool y diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index de70c1e..1ee22ff 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -555,6 +555,7 @@ static inline phys_addr_t pud_page_paddr(pud_t pud) #else +#define pmd_index(addr) 0 #define pud_page_paddr(pud) ({ BUILD_BUG(); 0; }) /* Match pmd_offset folding in */ @@ -612,6 +613,7 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd) #else +#define pud_index(adrr) 0 #define pgd_page_paddr(pgd) ({ BUILD_BUG(); 0;}) /* Match pud_offset folding in */ diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index ef82312..a4750fe 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -733,6 +733,194 @@ int kern_addr_valid(unsigned long addr) return pfn_valid(pte_pfn(pte)); } + +#ifdef CONFIG_MEMORY_HOTPLUG +static void free_pagetable(struct page *page, int order) +{ + unsigned long magic; + unsigned int nr_pages = 1 << order; + + if (PageReserved(page)) { + __ClearPageReserved(page); + + magic = (unsigned long)page->freelist; + if (magic == SECTION_INFO || magic == MIX_SECTION_INFO) { + while (nr_pages--) + put_page_bootmem(page++); + } else { + while (nr_pages--) + free_reserved_page(page++); + } + } else { + free_pages((unsigned long)page_address(page), order); + } +} + +#if (CONFIG_PGTABLE_LEVELS > 2) +static void free_pte_table(pte_t *pte_start, pmd_t *pmd) +{ + pte_t *pte; + int i; + + for (i = 0; i < PTRS_PER_PTE; i++) { + pte = pte_start + i; + if (!pte_none(*pte)) + return; + } + + free_pagetable(pmd_page(*pmd), 0); + spin_lock(&init_mm.page_table_lock); + pmd_clear(pmd); + spin_unlock(&init_mm.page_table_lock); +} +#else +static void free_pte_table(pte_t *pte_start, pmd_t *pmd) +{ +} +#endif + +#if (CONFIG_PGTABLE_LEVELS > 3) +static void free_pmd_table(pmd_t *pmd_start, pud_t *pud) +{ + pmd_t *pmd; + int i; + + for (i = 0; i < PTRS_PER_PMD; i++) { + pmd = pmd_start + i; + if (!pmd_none(*pmd)) + return; + } + + free_pagetable(pud_page(*pud), 0); + spin_lock(&init_mm.page_table_lock); + pud_clear(pud); + spin_unlock(&init_mm.page_table_lock); +} + +static void free_pud_table(pud_t *pud_start, pgd_t *pgd) +{ + pud_t *pud; + int i; + + for (i = 0; i < PTRS_PER_PUD; i++) { + pud = pud_start + i; + if (!pud_none(*pud)) + return; + } + + free_pagetable(pgd_page(*pgd), 0); + spin_lock(&init_mm.page_table_lock); + pgd_clear(pgd); + spin_unlock(&init_mm.page_table_lock); +} +#else +static void free_pmd_table(pmd_t *pmd_start, pud_t *pud) +{ +} + +static void free_pud_table(pud_t *pud_start, pgd_t *pgd) +{ +} +#endif + +static void +remove_pte_table(pte_t *pte_start, unsigned long addr, + unsigned long end, bool direct) +{ + pte_t *pte; + + pte = pte_start + pte_index(addr); + for (; addr < end; addr += PAGE_SIZE, pte++) { + if (!pte_present(*pte)) + continue; + + if (!direct) + free_pagetable(pte_page(*pte), 0); + spin_lock(&init_mm.page_table_lock); + pte_clear(&init_mm, addr, pte); + spin_unlock(&init_mm.page_table_lock); + } +} + +static void +remove_pmd_table(pmd_t *pmd_start, unsigned long addr, + unsigned long end, bool direct) +{ + unsigned long next; + pte_t *pte_base; + pmd_t *pmd; + + pmd = pmd_start + pmd_index(addr); + for (; addr < end; addr = next, pmd++) { + next = pmd_addr_end(addr, end); + if (!pmd_present(*pmd)) + continue; + + if (pmd_sect(*pmd)) { + if (!direct) + free_pagetable(pmd_page(*pmd), + get_order(PMD_SIZE)); + spin_lock(&init_mm.page_table_lock); + pmd_clear(pmd); + spin_unlock(&init_mm.page_table_lock); + continue; + } + pte_base = pte_offset_kernel(pmd, 0UL); + remove_pte_table(pte_base, addr, next, direct); + free_pte_table(pte_base, pmd); + } +} + +static void +remove_pud_table(pud_t *pud_start, unsigned long addr, + unsigned long end, bool direct) +{ + unsigned long next; + pmd_t *pmd_base; + pud_t *pud; + + pud = pud_start + pud_index(addr); + for (; addr < end; addr = next, pud++) { + next = pud_addr_end(addr, end); + if (!pud_present(*pud)) + continue; + + if (pud_sect(*pud)) { + if (!direct) + free_pagetable(pud_page(*pud), + get_order(PUD_SIZE)); + spin_lock(&init_mm.page_table_lock); + pud_clear(pud); + spin_unlock(&init_mm.page_table_lock); + continue; + } + pmd_base = pmd_offset(pud, 0UL); + remove_pmd_table(pmd_base, addr, next, direct); + free_pmd_table(pmd_base, pud); + } +} + +static void +remove_pagetable(unsigned long start, unsigned long end, bool direct) +{ + unsigned long addr, next; + pud_t *pud_base; + pgd_t *pgd; + + for (addr = start; addr < end; addr = next) { + next = pgd_addr_end(addr, end); + pgd = pgd_offset_k(addr); + if (!pgd_present(*pgd)) + continue; + + pud_base = pud_offset(pgd, 0UL); + remove_pud_table(pud_base, addr, next, direct); + free_pud_table(pud_base, pgd); + } + flush_tlb_kernel_range(start, end); +} +#endif + #ifdef CONFIG_SPARSEMEM_VMEMMAP #if !ARM64_SWAPPER_USES_SECTION_MAPS int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, @@ -780,6 +968,9 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, void vmemmap_free(unsigned long start, unsigned long end, struct vmem_altmap *altmap) { +#ifdef CONFIG_MEMORY_HOTPLUG + remove_pagetable(start, end, false); +#endif } #endif /* CONFIG_SPARSEMEM_VMEMMAP */ @@ -1065,10 +1256,16 @@ int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) } #ifdef CONFIG_MEMORY_HOTPLUG +static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) +{ + WARN_ON(pgdir != init_mm.pgd); + remove_pagetable(start, start + size, true); +} + int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, bool want_memblock) { - int flags = 0; + int ret, flags = 0; if (rodata_full || debug_pagealloc_enabled()) flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; @@ -1076,7 +1273,27 @@ int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), size, PAGE_KERNEL, __pgd_pgtable_alloc, flags); - return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, + ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, altmap, want_memblock); + if (ret) + __remove_pgd_mapping(swapper_pg_dir, + __phys_to_virt(start), size); + return ret; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + struct zone *zone = page_zone(pfn_to_page(start_pfn)); + int ret; + + ret = __remove_pages(zone, start_pfn, nr_pages, altmap); + if (!ret) + __remove_pgd_mapping(swapper_pg_dir, + __phys_to_virt(start), size); + return ret; +} +#endif #endif