On Thu, 14 Apr 2011, Dave Hansen wrote: > > What I really wanted in the end was a highmem-capable > alloc_pages_exact(), so here it is. This function can be used to > allocate unmapped (like highmem) non-power-of-two-sized areas of > memory. This is in constast to get_free_pages_exact() which can only > allocate from lowmem. > > My plan is to use this in the virtio_balloon driver to allocate large, > oddly-sized contiguous areas. > > The new __alloc_pages_exact() now takes a size in numbers of pages, > and returns a 'struct page', which means it can now address > highmem. The (new) argument order mirrors alloc_pages() itself. > > It's a bit unfortunate that this introduces __free_pages_exact() > alongside free_pages_exact(). But that mess already exists with > __free_pages() vs. free_pages_exact(). So, at worst, this mirrors the > mess that we already have. > > I'm also a bit worried that I've not put in something named > alloc_pages_exact(), but that behaves differently than it did before > this set. I got all of the in-tree cases, but I'm a bit worried about > stragglers elsewhere. So, I'm calling this __alloc_pages_exact() for > the moment. We can take out the __ some day if it bothers people. > > Note that the __get_free_pages() has a !GFP_HIGHMEM check. Now that > we are using alloc_pages_exact() instead of __get_free_pages() for > get_free_pages_exact(), we had to add a new check in > get_free_pages_exact(). > > This has been compile and boot tested, and I checked that > > echo 2 > /sys/kernel/profiling > > still works, since it uses get_free_pages_exact(). > > Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>