Messages in this thread | | | Date | Wed, 15 Mar 2023 17:41:53 +0100 | Subject | Re: [RFC 00/12] module: avoid userspace pressure on unwanted allocations | From | David Hildenbrand <> |
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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@kernel.org/ >>> >>> 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
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