Re: the new VMt

Alan Cox
2000-09-25T15:16:56Z

> > GFP_KERNEL has to be able to fail for 2.4. Otherwise you can get
> > everything jammed in kernel space waiting on GFP_KERNEL and if the
> > swapper cannot make space you die.
>
> if one can get everything jammed waiting for GFP_KERNEL, and not being
> able to deallocate anything, thats a VM or resource-limit bug. This
> situation is just 1% RAM away from the 'root cannot log in', situation.

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