Re: [PATCH 3/12 2.4] e1000 - use vmalloc for data structures not shared with h/w

From: Christoph Hellwig
Date: Wed Aug 04 2004 - 11:50:29 EST


On Sat, Jul 31, 2004 at 05:38:11PM +1000, Herbert Xu wrote:
> > No, it's not. vmalloc needs virtual space that's rather limited (e.g. 64MB
> > on PAE x86) in addition to physical memory. Unless you do really big
> > allocations stay away from vmalloc.
>
> How big is really big? 64K? 256K? 1M?

Well, the VM deals with big-order (aka bigger than page size) allocations
rather bad, so for allocation during any I/O I'd stick to allocation smaller
than that (and certainly no vmalloc!), for init-time allocations order 1 is
fine, maybe even order 2 or three.
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