mm/page_alloc.c low_on_memory variable.

Richard B. Johnson (root@chaos.analogic.com)
Fri, 16 Apr 1999 19:35:58 -0400 (EDT)


Hello mm gurus,

In page_alloc.c, defined in /include/linux/mm.h, is this wonderful
global variable that I'd love to see from a driver module. Unfortunately,
even though it is global, it is somehow invisible. It becomes an undefined
symbol if I attempt to use it in my module.

If I am not supposed to use this, how do I prevent a driver from crashing
the system by eating up all the free pages?

The driver that I am implementing should not have a fixed amount of pages
that it can use because it should be able to use more if there is more
memory available and less if less.

Presently, if I allocate pages to buffer an incomming data stream, and
using failure to obtain a free page as a throttle, it is way too late.
The machine will die a horrible death with out-of-memory errors for
everything including init. So I have to be able to check something
before I attempt to allocate another page.

Cheers,
Dick Johnson
***** FILE SYSTEM WAS MODIFIED *****
Penguin : Linux version 2.2.5 on an i686 machine (400.59 BogoMips).
Warning : It's hard to remain at the trailing edge of technology.

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