From: Michal Hocko <mhocko@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@linux-foundation.org>,
Phil Auld <pauld@redhat.com>
Subject: Re: [PATCH v2] sched/core: Don't use dying mm as active_mm of kthreads
Date: Mon, 29 Jul 2019 20:58:53 +0200 [thread overview]
Message-ID: <20190729185853.GJ9330@dhcp22.suse.cz> (raw)
In-Reply-To: <556445a2-8912-c017-413c-7a4f36c4b89e@redhat.com>
On Mon 29-07-19 11:27:35, Waiman Long wrote:
> On 7/29/19 5:12 AM, Michal Hocko wrote:
> > On Sat 27-07-19 13:10:47, Waiman Long wrote:
> >> It was found that a dying mm_struct where the owning task has exited
> >> can stay on as active_mm of kernel threads as long as no other user
> >> tasks run on those CPUs that use it as active_mm. This prolongs the
> >> life time of dying mm holding up memory and other resources like swap
> >> space that cannot be freed.
> > IIRC use_mm doesn't pin the address space. It only pins the mm_struct
> > itself. So what exactly is the problem here?
>
> As explained in my response to Peter, I found that resource like swap
> space were depleted even after the exit of the offending program in a
> mostly idle system. This patch is to make sure that those resources get
> freed after program exit ASAP.
Could you elaborate more? How can a mm counter (do not confuse with
mm_users) prevent address space to be torn down on exit?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-07-29 18:58 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-27 17:10 Waiman Long
2019-07-29 8:18 ` Qais Yousef
2019-07-29 21:06 ` Waiman Long
2019-07-29 21:33 ` Qais Yousef
2019-07-29 8:52 ` Peter Zijlstra
2019-07-29 14:24 ` [PATCH] sched: Clean up active_mm reference counting Peter Zijlstra
2019-07-29 15:01 ` Mathieu Desnoyers
2019-07-29 15:16 ` Waiman Long
2019-07-29 15:22 ` Peter Zijlstra
2019-07-29 15:29 ` Rik van Riel
2019-07-29 14:27 ` [PATCH v2] sched/core: Don't use dying mm as active_mm of kthreads Peter Zijlstra
2019-07-29 15:22 ` Waiman Long
2019-07-29 15:38 ` Peter Zijlstra
2019-07-29 14:51 ` Waiman Long
2019-07-29 15:03 ` Peter Zijlstra
2019-07-29 15:28 ` Rik van Riel
2019-07-29 15:44 ` Peter Zijlstra
2019-07-29 16:10 ` Rik van Riel
2019-07-29 16:26 ` Peter Zijlstra
2019-07-29 15:37 ` Waiman Long
2019-07-29 16:12 ` Rik van Riel
2019-07-29 16:22 ` Andy Lutomirski
2019-07-29 9:12 ` Michal Hocko
2019-07-29 15:27 ` Waiman Long
2019-07-29 18:58 ` Michal Hocko [this message]
2019-07-29 20:41 ` Waiman Long
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