Re: reliability of linux-vm subsystem

Erik Mouw
2000-11-13T13:08:59Z

On Mon, Nov 13, 2000 at 05:29:48PM +0530, aprasad@in.ibm.com wrote:
> When i run following code many times.
> System becomes useless till all of the instance of this programming are
> killed by vmm.

Good, so the OOM killer works.

> Till that time linux doesn't accept any command though it switches from one
> VT to another but its useless.

VT swithing is done by the kernel itself, not by a process.

> The above programme is run as normal user previleges.
> Theoretically load should increase but system should services other users
> too.

No. The system would *like* to service other processes, but it *can't*
because it is trashing.

> but this is not behaving in that way.
> ___________________________________________________________________
> main()
> {
> char *x[1000];
> int count=1000,i=0;
> for(i=0; i <count; i++)
> x[i] = (char*)malloc(1024*1024*10); /*10MB each time*/
>
> }
> _______________________________________________________________________
> If i run above programm for 10 times , then system is useless for around
> 5-7minutes on PIII/128MB.

Sounds quite normal to me. If you don't enforce process limits, you
allow a normal user to thrash the system.

Erik

--
J.A.K. (Erik) Mouw, Information and Communication Theory Group, Department
of Electrical Engineering, Faculty of Information Technology and Systems,
Delft University of Technology, PO BOX 5031, 2600 GA Delft, The Netherlands
Phone: +31-15-2783635 Fax: +31-15-2781843 Email: J.A.K.Mouw@its.tudelft.nl
WWW: http://www-ict.its.tudelft.nl/~erik/