Re: #define NR_TASKS ??
On Wed, 23 May 2001, Russell Coker wrote:
> Your kernel source is not corrupted, things are being done differently in
> 2.4.x.
>
> Here's some code from fork.c:
> max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 2;
Owwww damn, is it _still_ doing that ?
> So for my P3 laptop with 256M of RAM I'll have something like
> 16000 processes maximum.
>
> I have attached a program I wrote to test this. After about
> 4300 processes my machine started running extremely slow
As expected, at this time not only has over 1/4th of system memory
been taken by the task_struct's for those processes, but unswappable
memory is also being used for the page directory (1 page per proc),
the page tables (most likely 3 pages per proc), file descriptors,
address space structures, etc...
In short, memory has just about filled up with kernel structures.
A while ago I already proposed lowering the limit to something
like "max_threads = mempages / (THREAD_SIZE/PAGE_SIZE) / 10;"
exactly to prevent problems like this.
Expect a patch to go to Linus and Alan later today.
Another alternative would be real task swapping, but that's a
2.5 thing ;)
regards,
Rik
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