linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* Detecting page cache trashing state
@ 2017-09-15  0:16 Taras Kondratiuk
  2017-09-15 11:55 ` Zdenek Kabelac
                   ` (2 more replies)
  0 siblings, 3 replies; 21+ messages in thread
From: Taras Kondratiuk @ 2017-09-15  0:16 UTC (permalink / raw)
  To: linux-mm; +Cc: xe-linux-external, Ruslan Ruslichenko, linux-kernel

Hi

In our devices under low memory conditions we often get into a trashing
state when system spends most of the time re-reading pages of .text
sections from a file system (squashfs in our case). Working set doesn't
fit into available page cache, so it is expected. The issue is that
OOM killer doesn't get triggered because there is still memory for
reclaiming. System may stuck in this state for a quite some time and
usually dies because of watchdogs.

We are trying to detect such trashing state early to take some
preventive actions. It should be a pretty common issue, but for now we
haven't find any existing VM/IO statistics that can reliably detect such
state.

Most of metrics provide absolute values: number/rate of page faults,
rate of IO operations, number of stolen pages, etc. For a specific
device configuration we can determine threshold values for those
parameters that will detect trashing state, but it is not feasible for
hundreds of device configurations.

We are looking for some relative metric like "percent of CPU time spent
handling major page faults". With such relative metric we could use a
common threshold across all devices. For now we have added such metric
to /proc/stat in our kernel, but we would like to find some mechanism
available in upstream kernel.

Has somebody faced similar issue? How are you solving it?

^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2017-11-27  2:18 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-09-15  0:16 Detecting page cache trashing state Taras Kondratiuk
2017-09-15 11:55 ` Zdenek Kabelac
2017-09-15 14:22 ` Daniel Walker
2017-09-15 16:38   ` Taras Kondratiuk
2017-09-15 17:31     ` Daniel Walker
2017-09-15 14:36 ` Michal Hocko
2017-09-15 17:28   ` Taras Kondratiuk
2017-09-18 16:34     ` Johannes Weiner
2017-09-19 10:55       ` [PATCH 1/3] sched/loadavg: consolidate LOAD_INT, LOAD_FRAC macros kbuild test robot
2017-09-19 11:02       ` kbuild test robot
2017-09-28 15:49       ` Detecting page cache trashing state Ruslan Ruslichenko -X (rruslich - GLOBALLOGIC INC at Cisco)
2017-10-25 16:53         ` Daniel Walker
2017-10-25 17:54         ` Johannes Weiner
2017-10-27 20:19           ` Ruslan Ruslichenko -X (rruslich - GLOBALLOGIC INC at Cisco)
2017-11-20 19:40             ` Ruslan Ruslichenko -X (rruslich - GLOBALLOGIC INC at Cisco)
2017-11-27  2:18               ` Minchan Kim
2017-10-26  3:53         ` vinayak menon
2017-10-27 20:29           ` Ruslan Ruslichenko -X (rruslich - GLOBALLOGIC INC at Cisco)
2017-09-15 21:20   ` vcaputo
2017-09-15 23:40     ` Taras Kondratiuk
2017-09-18  5:55     ` Michal Hocko

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).