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From: Michal Hocko <mhocko@kernel.org>
To: Daniel Drake <drake@endlessm.com>
Cc: hannes@cmpxchg.org, Linux Kernel <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	Linux Upstreaming Team <linux@endlessm.com>,
	linux-block@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>, Balbir Singh <bsingharora@gmail.com>,
	Mike Galbraith <efault@gmx.de>, Oliver Yang <yangoliver@me.com>,
	Shakeel Butt <shakeelb@google.com>, xxx xxx <x.qendo@gmail.com>,
	Taras Kondratiuk <takondra@cisco.com>,
	Daniel Walker <danielwa@cisco.com>,
	Vinayak Menon <vinmenon@codeaurora.org>,
	Ruslan Ruslichenko <rruslich@cisco.com>,
	kernel-team@fb.com
Subject: Re: [PATCH 0/10] psi: pressure stall information for CPU, memory, and IO v2
Date: Tue, 17 Jul 2018 14:23:27 +0200	[thread overview]
Message-ID: <20180717122327.GG7193@dhcp22.suse.cz> (raw)
In-Reply-To: <CAD8Lp45W00ga-P-nb6iytgSGW4xwSzmaTHA87DOvSotN0S2edw@mail.gmail.com>

On Tue 17-07-18 07:13:52, Daniel Drake wrote:
> On Tue, Jul 17, 2018 at 6:25 AM, Michal Hocko <mhocko@kernel.org> wrote:
> > Yes this is really unfortunate. One thing that could help would be to
> > consider a trashing level during the reclaim (get_scan_count) to simply
> > forget about LRUs which are constantly refaulting pages back. We already
> > have the infrastructure for that. We just need to plumb it in.
> 
> Can you go into a bit more detail about that infrastructure and how we
> might detect which pages are being constantly refaulted? I'm
> interested in spending a few hours on this topic to see if I can come
> up with anything.

mm/workingset.c allows for tracking when an actual page got evicted.
workingset_refault tells us whether a give filemap fault is a recent
refault and activates the page if that is the case. So what you need is
to note how many refaulted pages we have on the active LRU list. If that
is a large part of the list and if the inactive list is really small
then we know we are trashing. This all sounds much easier than it will
eventually turn out to be of course but I didn't really get to play with
this much.

HTH even though it is not really thought through well.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2018-07-17 12:23 UTC|newest]

Thread overview: 83+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-12 17:29 [PATCH 0/10] psi: pressure stall information for CPU, memory, and IO v2 Johannes Weiner
2018-07-12 17:29 ` [PATCH 01/10] mm: workingset: don't drop refault information prematurely Johannes Weiner
2018-07-12 17:29 ` [PATCH 02/10] mm: workingset: tell cache transitions from workingset thrashing Johannes Weiner
2018-07-23 13:36   ` Arnd Bergmann
2018-07-23 15:23     ` Johannes Weiner
2018-07-23 15:35       ` Arnd Bergmann
2018-07-23 16:27         ` Johannes Weiner
2018-07-24 15:04           ` Will Deacon
2018-07-25 16:06             ` Will Deacon
2018-07-12 17:29 ` [PATCH 03/10] delayacct: track delays from thrashing cache pages Johannes Weiner
2018-07-12 17:29 ` [PATCH 04/10] sched: loadavg: consolidate LOAD_INT, LOAD_FRAC, CALC_LOAD Johannes Weiner
2018-07-12 17:29 ` [PATCH 05/10] sched: loadavg: make calc_load_n() public Johannes Weiner
2018-07-12 17:29 ` [PATCH 06/10] sched: sched.h: make rq locking and clock functions available in stats.h Johannes Weiner
2018-07-12 17:29 ` [PATCH 07/10] sched: introduce this_rq_lock_irq() Johannes Weiner
2018-07-12 17:29 ` [PATCH 08/10] psi: pressure stall information for CPU, memory, and IO Johannes Weiner
2018-07-13  9:21   ` Peter Zijlstra
2018-07-13 16:17     ` Johannes Weiner
2018-07-14  8:48       ` Peter Zijlstra
2018-07-14  9:02       ` Peter Zijlstra
2018-07-17 10:03   ` Peter Zijlstra
2018-07-18 21:56     ` Johannes Weiner
2018-07-17 14:16   ` Peter Zijlstra
2018-07-18 22:00     ` Johannes Weiner
2018-07-17 14:21   ` Peter Zijlstra
2018-07-18 22:03     ` Johannes Weiner
2018-07-17 15:01   ` Peter Zijlstra
2018-07-18 22:06     ` Johannes Weiner
2018-07-20 14:13       ` Johannes Weiner
2018-07-17 15:17   ` Peter Zijlstra
2018-07-18 22:11     ` Johannes Weiner
2018-07-17 15:32   ` Peter Zijlstra
2018-07-18 12:03   ` Peter Zijlstra
2018-07-18 12:22     ` Peter Zijlstra
2018-07-18 22:36     ` Johannes Weiner
2018-07-19 13:58       ` Peter Zijlstra
2018-07-19  9:26     ` Peter Zijlstra
2018-07-19 12:50       ` Johannes Weiner
2018-07-19 13:18         ` Peter Zijlstra
2018-07-19 15:08     ` Linus Torvalds
2018-07-19 17:54       ` Johannes Weiner
2018-07-19 18:47     ` Johannes Weiner
2018-07-19 20:31       ` Peter Zijlstra
2018-07-24 16:01         ` Johannes Weiner
2018-07-18 12:46   ` Peter Zijlstra
2018-07-18 13:56     ` Johannes Weiner
2018-07-18 16:31       ` Peter Zijlstra
2018-07-18 16:46         ` Johannes Weiner
2018-07-20 20:35   ` Peter Zijlstra
2018-07-12 17:29 ` [PATCH 09/10] psi: cgroup support Johannes Weiner
2018-07-12 20:08   ` Tejun Heo
2018-07-17 15:40   ` Peter Zijlstra
2018-07-24 15:54     ` Johannes Weiner
2018-07-12 17:29 ` [RFC PATCH 10/10] psi: aggregate ongoing stall events when somebody reads pressure Johannes Weiner
2018-07-12 23:45   ` Andrew Morton
2018-07-13 22:17     ` Johannes Weiner
2018-07-13 22:13   ` Suren Baghdasaryan
2018-07-13 22:49     ` Johannes Weiner
2018-07-13 23:34       ` Suren Baghdasaryan
2018-07-17 15:13   ` Peter Zijlstra
2018-07-12 17:37 ` [PATCH 0/10] psi: pressure stall information for CPU, memory, and IO v2 Linus Torvalds
2018-07-12 23:44 ` Andrew Morton
2018-07-13 22:14   ` Johannes Weiner
2018-07-16 15:57 ` Daniel Drake
2018-07-17 11:25   ` Michal Hocko
2018-07-17 12:13     ` Daniel Drake
2018-07-17 12:23       ` Michal Hocko [this message]
2018-07-25 22:57         ` Daniel Drake
2018-07-18 22:21     ` Johannes Weiner
2018-07-19 11:29       ` peter enderborg
2018-07-19 12:18         ` Johannes Weiner
2018-07-23 21:14 ` Balbir Singh
2018-07-24 15:15   ` Johannes Weiner
2018-07-26  1:07     ` Singh, Balbir
2018-07-26 20:07       ` Johannes Weiner
2018-07-27 23:40         ` Suren Baghdasaryan
2018-07-27 22:01 ` Pavel Machek
2018-07-30 15:40   ` Johannes Weiner
2018-07-30 17:39     ` Pavel Machek
2018-07-30 17:51       ` Tejun Heo
2018-07-30 17:54         ` Randy Dunlap
2018-07-30 18:05           ` Tejun Heo
2018-07-30 17:59         ` Pavel Machek
2018-07-30 18:07           ` Tejun Heo

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