Re: the new VM

Ingo Molnar
2000-09-25T15:33:59Z

On Mon, 25 Sep 2000, Alan Cox wrote:

> Unless Im missing something here think about this case
>
> 2 active processes, no swap
>
> #1 #2
> kmalloc 32K kmalloc 16K
> OK OK
> kmalloc 16K kmalloc 32K
> block block
>
> so GFP_KERNEL has to be able to fail - it can wait for I/O in some
> cases with care, but when we have no pages left something has to give

you are right, i agree that synchronous OOM for higher-order allocations
must be preserved (just like ATOMIC allocations). But the overwhelming
majority of allocations is done at page granularity.

with multi-page allocations and the need for physically contiguous
buffers, the problem cannot be solved.

Ingo