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From: Mike Galbraith <efault@gmx.de>
To: Michal Hocko <mhocko@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rt-users <linux-rt-users@vger.kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [rfc patch-rt] radix-tree: Partially disable memcg accounting in radix_tree_node_alloc()
Date: Fri, 06 Jan 2017 11:52:59 +0100	[thread overview]
Message-ID: <1483699979.11478.21.camel@gmx.de> (raw)
In-Reply-To: <20170106085548.GD5556@dhcp22.suse.cz>

On Fri, 2017-01-06 at 09:55 +0100, Michal Hocko wrote:
> On Fri 06-01-17 09:13:23, Mike Galbraith wrote:
> > radix-tree: Partially disable memcg accounting in radix_tree_node_alloc()
> > 
> > Having no preload, which turns accounting off for non-rt kernels, trying to
> > allocate coming from shmem_fault() when memcg is full sends us scurrying off
> > to pagefault_out_of_memory(), with dramatic (usually terminal) consequences.
> > LTP's madvise06 testcase triggers this quite well, and per gitk, the below
> > was the beginning of RT memcg woes.
> > 
> > 58e698af4c63 radix-tree: account radix_tree_node to memory cgroup
> > 
> > Turn memcg accounting off for RT in the problematic path.
> 
> I am really wondering why this is RT specific and the non RT kernels
> doesn't have any problem.

For all I know, there may be a scenario for non-RT to explode, but the
madvise06 testcase that thoroughly nails RT ain't it.

	-Mike

  reply	other threads:[~2017-01-06 10:52 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-23 16:32 [ANNOUNCE] v4.9-rt1 Sebastian Andrzej Siewior
2016-12-26  6:54 ` [patch-rt] kvm: Convert pvclock_gtod_sync_lock to raw_spinlock_t Mike Galbraith
2017-01-20 16:44   ` Sebastian Andrzej Siewior
2017-01-20 17:32     ` Mike Galbraith
2016-12-26  7:00 ` [rfc patch-rt] posix_cpu_timers: Kill hotplug cpu notifier Mike Galbraith
2017-01-20 16:46   ` Sebastian Andrzej Siewior
2017-01-20 17:29     ` Mike Galbraith
2017-01-20 17:34       ` Sebastian Andrzej Siewior
2017-01-20 17:56         ` Mike Galbraith
2016-12-31  8:20 ` [patch-rt] softirq: Move ksoftirqd_running() under !CONFIG_PREEMPT_RT_FULL Mike Galbraith
2017-01-20 17:21   ` Sebastian Andrzej Siewior
2017-01-06  8:13 ` [rfc patch-rt] radix-tree: Partially disable memcg accounting in radix_tree_node_alloc() Mike Galbraith
2017-01-06  8:28   ` Mike Galbraith
2017-01-06  8:55   ` Michal Hocko
2017-01-06 10:52     ` Mike Galbraith [this message]
2017-01-06 12:20       ` Mike Galbraith
2017-01-06 12:44         ` Mike Galbraith
2017-01-25 15:06   ` Sebastian Andrzej Siewior
2017-01-26  3:42     ` Mike Galbraith
2017-01-08  8:32 ` {patch-rt] cpuset: Convert callback_lock to raw_spinlock_t Mike Galbraith
2017-01-25 15:45   ` Sebastian Andrzej Siewior

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