Re: VM fixes [2/4]

[Nick Piggin <nickpiggin@yahoo.com.au>]

Andrea Arcangeli wrote:
> This is the forward port to 2.6 of the lowmem_reserved algorithm I
> invented in 2.4.1*, merged in 2.4.2x already and needed to fix workloads
> like google (especially without swap) on x86 with >1G of ram, but it's
> needed in all sort of workloads with lots of ram on x86, it's also
> needed on x86-64 for dma allocations. This brings 2.6 in sync with
> latest 2.4.2x.
> 

This looks OK to me. It really simplifies the code there a lot too.

The only questions I have are: should it be on by default? I don't think
we ever reached an agreement. I'd say yes, after a run in -mm because it
does potentially fix corner cases where lower zones get filled with un-
freeable memory which could have been satisfied with higher zones.

And second, any chance you could you port it to the mm patches already in
-mm? Won't be a big job, just some clashes in __alloc_pages...

mm-keep-count-of-free-areas.patch
mm-higher-order-watermarks.patch
mm-higher-order-watermarks-fix.patch
mm-teach-kswapd-about-higher-order-areas.patch

Thanks,
Nick