Re: fork: out of memory

Pavel Machek (pavel@Elf.mj.gts.cz)
Tue, 25 Nov 1997 23:04:39 +0100


Hi!

> I must be missing a big point here ... why is it not
> possible to either (a) turn on paging in the kernel
> so that non-contiguous pages can be easily made to look
> contiguous to kernel code, or (b) when you can't find

a) is bad: linux performs so good partly because its own ram is
unswapable.

> 8 contiguous pages, pick the first free page and swap
> the data in the next 7 adjacent pages with other free

b) is impossible: You would have to modify all pointers pointing to
that memory. Or you would have to use MM tricks which are slow - see
a).

> pages in memory. Method (b) could construct any number of
> contiguous free pages atomically with the only penalty
> being some chunky memcpy's ...

Pavel

-- 
I'm really pavel@atrey.karlin.mff.cuni.cz. 	   Pavel
Look at http://atrey.karlin.mff.cuni.cz/~pavel/ ;-).