From patchwork Mon Feb 15 16:13:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pasha Tatashin X-Patchwork-Id: 12088941 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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 3A0E7C433E0 for ; Mon, 15 Feb 2021 16:24:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0519D64E05 for ; Mon, 15 Feb 2021 16:24:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231680AbhBOQXk (ORCPT ); Mon, 15 Feb 2021 11:23:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231962AbhBOQRp (ORCPT ); Mon, 15 Feb 2021 11:17:45 -0500 Received: from mail-qk1-x730.google.com (mail-qk1-x730.google.com [IPv6:2607:f8b0:4864:20::730]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1D52AC0611BC for ; Mon, 15 Feb 2021 08:14:05 -0800 (PST) Received: by mail-qk1-x730.google.com with SMTP id z190so893052qka.9 for ; Mon, 15 Feb 2021 08:14:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=38wDBdME2LupaBaoyY01V6Pw/ZXOdtQ/YB6thxCvT6c=; b=a5+vYsvd2IfA6SFLlrkem8EeYtmqX6ARwpEfK9m5AqHki60j7f5AS5qbJKtGXG777k rS3Ex4AZdJamhlAKxZx4eE/il8uQMphmyQ00jFYxOTZnfVcLZffR5ZFc/h2CzMee5JXG LOqIhFGOtJPazR6r6k+FLMdrShIx0VFTnvL68OGnvrNLy4yVoa1ILrB2CgjULLXlh/tr a2zE/rFz58GK6fdRdZ8n4zBb0dl7rlliQwq9x/Jbx4xW8f+C+DjKAhF5GS9RgiDXTZLt JQUOvvYLCsmyScZkQk+x0WBR9kVOQn1KrJVM22LVSULFNY4ZU3uY8HBcYdXvuepmWwx9 Znxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=38wDBdME2LupaBaoyY01V6Pw/ZXOdtQ/YB6thxCvT6c=; b=Gz0n+zKz/JtbRURT1iWe/rtXws3tDTAb5a04TDGp51TwGlV5fwwjdaMn0/xqx9QH/J VlI0X4wpWcuxT5N/Taboo/CnxHycf3/ixiaKtDGuJSBm9/8W8mRAiemaHK7PUXjU3PBY Y+BQ9fSGtzAK7DBkWuIPHIYAKfftWETyaikSvvEaB1InIHVPYw31ZqGGy1unY/Paoi25 PqOFTdXoOeMa8lS7eLKtiQ91JOIXE+9o3KFt2Va8FmGB7LysPinKz/7Jibcp75JIIVsR 1pnmE1ufK9QuEYSKFCI+fm4TAXPrXJ+AnSNBIsmsgBjPowEss/R4+mcpknwRNIsnwt+1 SfmQ== X-Gm-Message-State: AOAM532ceAPlhJtiwsl9usPb+u90pxYhDEq3IBxCVzbOGwWXWKjyOin+ 1Kk7kLCJmPsDEJImN3/+hN9QOA== X-Google-Smtp-Source: ABdhPJxWdJ09keZeKYoYN0ga+vu74hTzd8SZNUWhh++aQD00fFcf8dANY1Nyi/4IUDyARNVskiqOfw== X-Received: by 2002:a05:620a:1643:: with SMTP id c3mr15703452qko.369.1613405644373; Mon, 15 Feb 2021 08:14:04 -0800 (PST) Received: from localhost.localdomain (c-73-69-118-222.hsd1.nh.comcast.net. [73.69.118.222]) by smtp.gmail.com with ESMTPSA id u7sm10909213qta.75.2021.02.15.08.14.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Feb 2021 08:14:03 -0800 (PST) From: Pavel Tatashin To: pasha.tatashin@soleen.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz, mhocko@suse.com, david@redhat.com, osalvador@suse.de, dan.j.williams@intel.com, sashal@kernel.org, tyhicks@linux.microsoft.com, iamjoonsoo.kim@lge.com, mike.kravetz@oracle.com, rostedt@goodmis.org, mingo@redhat.com, jgg@ziepe.ca, peterz@infradead.org, mgorman@suse.de, willy@infradead.org, rientjes@google.com, jhubbard@nvidia.com, linux-doc@vger.kernel.org, ira.weiny@intel.com, linux-kselftest@vger.kernel.org, jmorris@namei.org Subject: [PATCH v11 08/14] mm/gup: do not migrate zero page Date: Mon, 15 Feb 2021 11:13:43 -0500 Message-Id: <20210215161349.246722-9-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210215161349.246722-1-pasha.tatashin@soleen.com> References: <20210215161349.246722-1-pasha.tatashin@soleen.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On some platforms ZERO_PAGE(0) might end-up in a movable zone. Do not migrate zero page in gup during longterm pinning as migration of zero page is not allowed. For example, in x86 QEMU with 16G of memory and kernelcore=5G parameter, I see the following: Boot#1: zero_pfn 0x48a8d zero_pfn zone: ZONE_DMA32 Boot#2: zero_pfn 0x20168d zero_pfn zone: ZONE_MOVABLE On x86, empty_zero_page is declared in .bss and depending on the loader may end up in different physical locations during boots. Also, move is_zero_pfn() my_zero_pfn() functions under CONFIG_MMU, because zero_pfn that they are using is declared in memory.c which is compiled with CONFIG_MMU. Signed-off-by: Pavel Tatashin --- include/linux/mm.h | 3 ++- include/linux/mmzone.h | 4 ++++ include/linux/pgtable.h | 12 ++++++++++++ 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 7f56d8d62148..3c75df55ed00 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1496,7 +1496,8 @@ static inline unsigned long page_to_section(const struct page *page) #ifdef CONFIG_MIGRATION static inline bool is_pinnable_page(struct page *page) { - return !is_zone_movable_page(page) && !is_migrate_cma_page(page); + return !(is_zone_movable_page(page) || is_migrate_cma_page(page)) || + is_zero_pfn(page_to_pfn(page)); } #else static inline bool is_pinnable_page(struct page *page) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index b593316bff3d..c56f508be031 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -407,6 +407,10 @@ enum zone_type { * techniques might use alloc_contig_range() to hide previously * exposed pages from the buddy again (e.g., to implement some sort * of memory unplug in virtio-mem). + * 6. ZERO_PAGE(0), kernelcore/movablecore setups might create + * situations where ZERO_PAGE(0) which is allocated differently + * on different platforms may end up in a movable zone. ZERO_PAGE(0) + * cannot be migrated. * * In general, no unmovable allocations that degrade memory offlining * should end up in ZONE_MOVABLE. Allocators (like alloc_contig_range()) diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 8fcdfa52eb4b..7c6cba3d80f0 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -1115,6 +1115,7 @@ extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, extern void untrack_pfn_moved(struct vm_area_struct *vma); #endif +#ifdef CONFIG_MMU #ifdef __HAVE_COLOR_ZERO_PAGE static inline int is_zero_pfn(unsigned long pfn) { @@ -1138,6 +1139,17 @@ static inline unsigned long my_zero_pfn(unsigned long addr) return zero_pfn; } #endif +#else +static inline int is_zero_pfn(unsigned long pfn) +{ + return 0; +} + +static inline unsigned long my_zero_pfn(unsigned long addr) +{ + return 0; +} +#endif /* CONFIG_MMU */ #ifdef CONFIG_MMU