> > After simple bash fork bombing (about 200 forks) on my UP Celeron/96MB
> > I get quite a lot %u-allocations failed, but only when swap is turned
> > off.
>
> > I'm not familiar with LinuxVM.. so... is it normal behaviour ? or (if not)
> > what's happening when such messages are printed my kernel ?
>
> This is perfectly normal behaviour:
>
> 1) on your system, you have no process limit configured for
> yourself so you can start processes until all resources
> (memory, file descriptors, ...) are used
>
> 2) when all processes are used, there really is no way the
> kernel can buy you more hardware on ebay and install it
> on the fly ... all it can do is start failing allocations
>
> On production systems, good admins setup per-user limits for
> the various resources so no single user is able to run the
> system into the ground.
No, it's not normal. It is long-standing bug - I think from 2.2 kernels.
You know that without swap and with certain memory allocation strategy
(when process in a loop allocates one anonymous page, one file cache page
and again...) this bug can be triggered even when there is half memory
free.
Buddy allocator is broken - kill it. Or at least do not misuse it for
anything except kernel or driver initialization.
Mikulas
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