From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43556 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962AbeCVNvX (ORCPT ); Thu, 22 Mar 2018 09:51:23 -0400 Subject: Patch "oom: improve oom disable handling" has been added to the 4.9-stable tree To: mhocko@suse.com, akpm@linux-foundation.org, alexander.levin@microsoft.com, gregkh@linuxfoundation.org, penguin-kernel@I-love.SAKURA.ne.jp, torvalds@linux-foundation.org Cc: , From: Date: Thu, 22 Mar 2018 14:49:48 +0100 Message-ID: <152172658820292@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled oom: improve oom disable handling to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: oom-improve-oom-disable-handling.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Thu Mar 22 14:40:24 CET 2018 From: Michal Hocko Date: Wed, 3 May 2017 14:54:57 -0700 Subject: oom: improve oom disable handling From: Michal Hocko [ Upstream commit d75da004c708c9fca7b53f7da293a295522414d9 ] Tetsuo has reported that sysrq triggered OOM killer will print a misleading information when no tasks are selected: sysrq: SysRq : Manual OOM execution Out of memory: Kill process 4468 ((agetty)) score 0 or sacrifice child Killed process 4468 ((agetty)) total-vm:43704kB, anon-rss:1760kB, file-rss:0kB, shmem-rss:0kB sysrq: SysRq : Manual OOM execution Out of memory: Kill process 4469 (systemd-cgroups) score 0 or sacrifice child Killed process 4469 (systemd-cgroups) total-vm:10704kB, anon-rss:120kB, file-rss:0kB, shmem-rss:0kB sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled sysrq: SysRq : Manual OOM execution sysrq: OOM request ignored because killer is disabled The real reason is that there are no eligible tasks for the OOM killer to select but since commit 7c5f64f84483 ("mm: oom: deduplicate victim selection code for memcg and global oom") the semantic of out_of_memory has changed without updating moom_callback. This patch updates moom_callback to tell that no task was eligible which is the case for both oom killer disabled and no eligible tasks. In order to help distinguish first case from the second add printk to both oom_killer_{enable,disable}. This information is useful on its own because it might help debugging potential memory allocation failures. Fixes: 7c5f64f84483 ("mm: oom: deduplicate victim selection code for memcg and global oom") Link: http://lkml.kernel.org/r/20170404134705.6361-1-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Tetsuo Handa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/tty/sysrq.c | 2 +- mm/oom_kill.c | 2 ++ 2 files changed, 3 insertions(+), 1 deletion(-) --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -375,7 +375,7 @@ static void moom_callback(struct work_st mutex_lock(&oom_lock); if (!out_of_memory(&oc)) - pr_info("OOM request ignored because killer is disabled\n"); + pr_info("OOM request ignored. No task eligible\n"); mutex_unlock(&oom_lock); } --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -706,6 +706,7 @@ void exit_oom_victim(void) void oom_killer_enable(void) { oom_killer_disabled = false; + pr_info("OOM killer enabled.\n"); } /** @@ -742,6 +743,7 @@ bool oom_killer_disable(signed long time oom_killer_enable(); return false; } + pr_info("OOM killer disabled.\n"); return true; } Patches currently in stable-queue which might be from mhocko@suse.com are queue-4.9/mm-fix-check-for-reclaimable-pages-in-pf_memalloc-reclaim-throttling.patch queue-4.9/oom-improve-oom-disable-handling.patch