From: John Moser <john.r.moser@gmail.com>
To: linux-kernel@vger.kernel.org
Subject: OOM at low page cache?
Date: Fri, 23 Jan 2015 17:18:04 -0500 [thread overview]
Message-ID: <54C2C89C.8080002@gmail.com> (raw)
Why is there no tunable to OOM at low page cache?
I have no swap configured. I have 16GB RAM. If Chrome or Gimp or some
other stupid program goes off the deep end and eats up my RAM, I hit
some 15.5GB or 15.75GB usage and stay there for about 40 minutes. Every
time the program tries to do something to eat more RAM, it cranks disk
hard; the disk starts thrashing, the mouse pointer stops moving, and
nothing goes on. It's like swapping like crazy, except you're reading
library files instead of paged anonymous RAM.
If only I could tell the system to OOM kill at 512MB or 1GB or 95%
non-evictable RAM, it would recover on its own. As-is, I need to wait
or trigger the OOM killer by sysrq.
Am I just the only person in the world who's ever had that problem? Or
is it a matter of questions fast popping up when you try to do this
*and* enable paging to disk? (In my experience, that's a matter of too
much swap space: if you have 16GB RAM and your computer dies at 15.25GB
usage, your swap space should be no larger than 750MB plus inactive
working RAM; obviously, your computer can't handle paging 750MB back and
forth. If you make it 8GB wide and you start swap thrashing at 2GB
usage, you have too much swap available).
I guess you could try to detect excessive swap and page cache thrashing,
but that's complex; if anyone really wanted to do that, it would be done
by now. A low-barrier OOM is much simpler.
next reply other threads:[~2015-01-23 22:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-23 22:18 John Moser [this message]
2015-01-27 11:03 ` OOM at low page cache? Vlastimil Babka
2015-01-28 6:26 ` Minchan Kim
2015-01-28 12:36 ` Rik van Riel
2015-01-28 14:15 ` John Moser
2015-01-29 1:24 ` Minchan Kim
2015-01-28 14:27 ` John Moser
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