2.6.8.1 mempool subsystem sickness

From: jmerkey
Date: Wed Sep 08 2004 - 11:50:10 EST


On a system with 4GB of memory, and without
the user space patch that spilts user space
just a stock kernel, I am seeing memory
allocation failures with X server and simple
apps on a machine with a Pentium 4
processor and 500MB of memory.

If you load large apps and do a lot of
skb traffic, the mempool abd slab
caches start gobbling up pages
and don't seem to balance them
very well, resulting in memory
allocation failures over time if
the system stays up for a week
or more.

I am also seeing the same behavior
on another system which has been
running for almost 30 days with
an skb based traffic regeneration
test calling and sending skb's
in kernel between two interfaces.

The pages over time get stuck
in the slab allocator and user
space apps start to fail on alloc
requests.

Rebooting the system clears
the problem, which slowly over time
comes back. I am seeing this with
stock kernels from kernel.org
and on kernels I have patched,
so the problem seems to be
in the base code. I have spent
the last two weeks observing
the problem to verify I can
reproduce it and it keeps
happening.

Jeff

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