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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 F008BC433DF for ; Fri, 16 Oct 2020 03:07:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9FEEC2087D for ; Fri, 16 Oct 2020 03:07:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602817673; bh=HBgidZIBSKhm02N61qN8wLnnIq23T+fV1TubSu9maqs=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=UYQv8QwwKyxTD711MwSpHyt9+YLHwswA0cHd05NUvh/jP9r903NCaxIlTlZcL55TK HtoCW4owy8/JwS+TqfsU26CGysxtLSO1hw/3ApsFC6lJ5Vv9az5adiMh48aXSqQojz sMyRki+dOPx8Ihi5mNa3D3tcGXZ14nAu+gG6iygM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732759AbgJPDHx (ORCPT ); Thu, 15 Oct 2020 23:07:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:45672 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727382AbgJPDHx (ORCPT ); Thu, 15 Oct 2020 23:07:53 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 460B420878; Fri, 16 Oct 2020 03:07:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602817672; bh=HBgidZIBSKhm02N61qN8wLnnIq23T+fV1TubSu9maqs=; h=Date:From:To:Subject:In-Reply-To:From; b=ZwG0Vwl8TPqGBQuPWswZAi2cKFhlm0fSt1ou/E7t09mVtqM07nsoEsZc5MwYd5T8a 7BYVCLWBxxuo+BEk3d8af0PjAgz127rvPCmkNHk91RycZsG1ImS4g6jGsyvP+x+liq K7t2gf6EpCVJ9H5fGYx/kSeXyMuHznbUM5KhRayM= Date: Thu, 15 Oct 2020 20:07:50 -0700 From: Andrew Morton To: akpm@linux-foundation.org, bhe@redhat.com, charante@codeaurora.org, dan.j.williams@intel.com, david@redhat.com, fenghua.yu@intel.com, logang@deltatee.com, mgorman@suse.de, mgorman@techsingularity.net, mhocko@suse.com, mm-commits@vger.kernel.org, osalvador@suse.de, pankaj.gupta.linux@gmail.com, richard.weiyang@linux.alibaba.com, rppt@kernel.org, tony.luck@intel.com, torvalds@linux-foundation.org, walken@google.com, willy@infradead.org Subject: [patch 060/156] mm/memory_hotplug: enforce section granularity when onlining/offlining Message-ID: <20201016030750.d5x9kRuZO%akpm@linux-foundation.org> In-Reply-To: <20201015194043.84cda0c1d6ca2a6847f2384a@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: David Hildenbrand Subject: mm/memory_hotplug: enforce section granularity when onlining/offlining Already two people (including me) tried to offline subsections, because the function looks like it can deal with it. But we really can only online/offline full sections that are properly aligned (e.g., we can only mark full sections online/offline via SECTION_IS_ONLINE). Add a simple safety net to document the restriction now. Current users (core and powernv/memtrace) respect these restrictions. Link: https://lkml.kernel.org/r/20200819175957.28465-3-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Michal Hocko Reviewed-by: Oscar Salvador Cc: Wei Yang Cc: Baoquan He Cc: Pankaj Gupta Cc: Charan Teja Reddy Cc: Dan Williams Cc: Fenghua Yu Cc: Logan Gunthorpe Cc: "Matthew Wilcox (Oracle)" Cc: Mel Gorman Cc: Mel Gorman Cc: Michel Lespinasse Cc: Mike Rapoport Cc: Tony Luck Signed-off-by: Andrew Morton --- mm/memory_hotplug.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/mm/memory_hotplug.c~mm-memory_hotplug-enforce-section-granularity-when-onlining-offlining +++ a/mm/memory_hotplug.c @@ -809,6 +809,11 @@ int __ref online_pages(unsigned long pfn int ret; struct memory_notify arg; + /* We can only online full sections (e.g., SECTION_IS_ONLINE) */ + if (WARN_ON_ONCE(!nr_pages || + !IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION))) + return -EINVAL; + mem_hotplug_begin(); /* associate pfn range with the zone */ @@ -1494,6 +1499,11 @@ int __ref offline_pages(unsigned long st struct memory_notify arg; char *reason; + /* We can only offline full sections (e.g., SECTION_IS_ONLINE) */ + if (WARN_ON_ONCE(!nr_pages || + !IS_ALIGNED(start_pfn | nr_pages, PAGES_PER_SECTION))) + return -EINVAL; + mem_hotplug_begin(); /* _