Re: [rfc][patch 0/3] bootmem2: a memory block-oriented boot time allocator

Linus Torvalds
2008-05-05T15:23:34Z

On Mon, 5 May 2008, Johannes Weiner wrote:
>
> here is a bootmem allocator replacement that uses one bitmap for all
> available pages and works with a model of contiguous memory blocks
> that reside on nodes instead of nodes only as the current allocator
> does.

Won't this have problems with huge non-contiguous areas?

Some setups have traditionally had node memory separated in physical space
by the high bits of the memory address, and using a single bitmap for such
things would potentially be basically impossible - even with a single bit
per page, the "span" of possible pages is potentially just too high, even
if the nodes themselves don't have tons of memory, because the memory is
just very spread out - and allocating the initial bitmap may not work
reliably.

Now, admittedly I don't know if we even support that kind of thing or if
people really do things that way any more, so maybe it's not an issue.

Linus