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=-3.0 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_GIT autolearn=ham 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 735D9C0044C for ; Wed, 7 Nov 2018 10:18:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 341582081D for ; Wed, 7 Nov 2018 10:18:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 341582081D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726682AbeKGTs0 (ORCPT ); Wed, 7 Nov 2018 14:48:26 -0500 Received: from mail-wr1-f67.google.com ([209.85.221.67]:45883 "EHLO mail-wr1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726248AbeKGTsZ (ORCPT ); Wed, 7 Nov 2018 14:48:25 -0500 Received: by mail-wr1-f67.google.com with SMTP id k15-v6so13776131wre.12 for ; Wed, 07 Nov 2018 02:18:43 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=sxkTZHicSbXm+D7X6j1gdenRf/8OtsBZxrvgNV+3/Pg=; b=NZ/HNQKfXFk87vSx7WKyzfkP11KUm/XJu19ZWms8uWnX/vASH8gvGlj+XuPGIBXcHa yy9LNPP1Pb5R4shDnaGpmNLeFCn/cIMjjD6MGFA2094YlGC8EiI95s6RXp8kSbkPuy2V vu0h8AsG/7ZX3gsIld7E5seHgxdWj6Gu0kQb5j3mTxQ9Nr/YrsYf/8TQ4YC1eM7PJUzm TD8L1T5OP1vdN8zJQI+VpguARwfnctfyVMEqpQFICdwqBmdEH9OX0dksebXBnQ3/Lhnb P4x2zohFYV411r8aJYY/JKkzG+66qp8LuBzeD+Jd3pJ9fdHeRDlt3ogFfYIWhuOyvXW5 OT/w== X-Gm-Message-State: AGRZ1gI7nfgTtLJQV05Oi2ekTttvFr1mq8VaaJhPFPA9Bjgj1IsCgYx5 JhqKdt2YMBAIJic3CDn/s1M= X-Google-Smtp-Source: AJdET5da/PJmeqaS7uG3tevVjQEiAicJwUhwTYG/DXJZBvyXu+4NAQE6fmMLtBUfV9NkYzZKD8BCcg== X-Received: by 2002:a05:6000:1048:: with SMTP id c8mr1278377wrx.171.1541585922651; Wed, 07 Nov 2018 02:18:42 -0800 (PST) Received: from tiehlicka.suse.cz (ip-37-188-140-85.eurotel.cz. [37.188.140.85]) by smtp.gmail.com with ESMTPSA id w18-v6sm217527wrn.66.2018.11.07.02.18.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Nov 2018 02:18:42 -0800 (PST) From: Michal Hocko To: Cc: Andrew Morton , Oscar Salvador , Baoquan He , LKML Subject: [RFC PATCH 0/5] mm, memory_hotplug: improve memory offlining failures debugging Date: Wed, 7 Nov 2018 11:18:25 +0100 Message-Id: <20181107101830.17405-1-mhocko@kernel.org> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I have been promissing to improve memory offlining failures debugging for quite some time. As things stand now we get only very limited information in the kernel log when the offlining fails. It is usually only [ 1984.506184] rac1 kernel: memory offlining [mem 0x82600000000-0x8267fffffff] failed without no further details. We do not know what exactly fails and for what reason. Whenever I was forced to debug such a failure I've always had to do a debugging patch to tell me more. We can enable some tracepoints but it would be much better to get a better picture without using them. This patch series does 2 things. The first one is to make dump_page more usable by printing more information about the mapping patch 1. Then it reduces the log level from emerg to warning so that this function is usable from less critical context patch 2. Then I have added more detailed information about the offlining failure patch 4 and finally add dump_page to isolation and offlining migration paths. Patch 3 is a trivial cleanup. Does this look go to you? Shortlog Michal Hocko (5): mm: print more information about mapping in __dump_page mm: lower the printk loglevel for __dump_page messages mm, memory_hotplug: drop pointless block alignment checks from __offline_pages mm, memory_hotplug: print reason for the offlining failure mm, memory_hotplug: be more verbose for memory offline failures Diffstat: mm/debug.c | 23 ++++++++++++++++++----- mm/memory_hotplug.c | 52 +++++++++++++++++++++++++++++++--------------------- mm/page_alloc.c | 1 + 3 files changed, 50 insertions(+), 26 deletions(-)