On 15.03.23 17:10, Luis Chamberlain wrote:
On Wed, Mar 15, 2023 at 01:24:41PM +0100, David Hildenbrand wrote:
On 11.03.23 06:17, Luis Chamberlain wrote:
A long time ago we had some issues with userspace doing stupid stuff.
Well, it turns out even the kernel and do stupid stuff too, as we're
learning with the ACPI modules aliaes and that hammering tons of loads.
So add a bit of code which gets us a bit more in the defensive about
these situations.
To experiment, this also adds in-kernel alias support to see if this helps
with some larger systems.
This is all based on some old code which tried to add defensive
mechanisms the last of which was here and I had dropped the ball:
https://lore.kernel.org/all/20171208001540.23696-1-mcgrof@xxxxxxxxxx/
I've only compile tested this for now. Will need to stress to test
with kmod tests 0008 and 0009 to see if there's any differences.
I'll have to re-test and re-gnuplot stuff there. But early feedback
is appreciated, hence the RFC.
David Hildenbrand had reported a while ago issues with userspace
doing insane things with allocations bringing a system down to
its knees. This is part of the motivation for this series.
I'll try to grab a system where I can reproduce the issue and give your
patches a churn.
Great, then please wait for v2 RFC as the first patch was missing an
obvious mutex grab / release, I already have some memory pressure data
that shows gains. Hope to post soon.
I expect to have a machine (with a crazy number of CPUs/devices)
available in a couple of days (1-2), so no need to rush.
The original machine I was able to reproduce with is blocked for a
little bit longer; so I hope the alternative I looked up will similarly
trigger the issue easily.
--
Thanks,
David / dhildenb
