From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by kanga.kvack.org (Postfix) with ESMTP id F086B6B04DD for ; Wed, 7 Nov 2018 05:18:44 -0500 (EST) Received: by mail-wr1-f72.google.com with SMTP id 88-v6so14887528wrp.21 for ; Wed, 07 Nov 2018 02:18:44 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id z3-v6sor176996wru.7.2018.11.07.02.18.43 for (Google Transport Security); Wed, 07 Nov 2018 02:18:43 -0800 (PST) From: Michal Hocko 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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Andrew Morton , Oscar Salvador , Baoquan He , LKML 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(-)