Re: Memory management...

From: Richard B. Johnson (root@chaos.analogic.com)
Date: Thu Aug 03 2000 - 07:09:57 EST


On Wed, 2 Aug 2000, Tigran Aivazian wrote:

> On Wed, 2 Aug 2000, Richard B. Johnson wrote:
> > So what did you expect? Now turn on user limits.
>
> did you actually try your own suggestion? Iwas rather puzzled by the fact
> that turning on the user limits is obviously not enough. Or at least not
> the obvious user limits (RLIMIT_DATA, RLIMIT_STACK, RLIMIT_RSS) but a
> rather unobvious one - RLIMIT_AS. This is because malloc(3) uses not just
> brk(2) system call (which honours RLIMIT_DATA) but
> mmap(MAP_PRIVATE|MAP_ANONYMOUS) which honours RLIMIT_AS.

No I did not. If the writer had said they he had found a way to bypass
user limits then I would have been more receptive. However, merely
submitting some code that will run the system out of memory and
stating that it will lock up the system, left no hint that he was
using user limits. Also, where did you find that he was using a
special malloc()? DEFAULT_MMAP_THRESHOLD on glibc-2.0.6 that I have the
source for is 128 * 1024. His code does not magically hit a boundary.

Cheers,
Dick Johnson

Penguin : Linux version 2.2.15 on an i686 machine (797.90 BogoMips).

"Memory is like gasoline. You use it up when you are running. Of
course you get it all back when you reboot..."; Actual explanation
obtained from the Micro$oft help desk.

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