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author | Bjorn Helgaas <bjorn.helgaas@hp.com> | 2010-10-27 01:41:33 +0400 |
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committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-10-27 02:33:31 +0400 |
commit | e7f8567db9a7f6b3151b0b275e245c1cef0d9c70 (patch) | |
tree | f04a01581e86ec2b8c175b9f27648679c70d592c /include | |
parent | a1862e31079149a52b6223776228c3aee493d4a7 (diff) | |
download | linux-e7f8567db9a7f6b3151b0b275e245c1cef0d9c70.tar.xz |
resources: support allocating space within a region from the top down
Allocate space from the top of a region first, then work downward,
if an architecture desires this.
When we allocate space from a resource, we look for gaps between children
of the resource. Previously, we always looked at gaps from the bottom up.
For example, given this:
[mem 0xbff00000-0xf7ffffff] PCI Bus 0000:00
[mem 0xbff00000-0xbfffffff] gap -- available
[mem 0xc0000000-0xdfffffff] PCI Bus 0000:02
[mem 0xe0000000-0xf7ffffff] gap -- available
we attempted to allocate from the [mem 0xbff00000-0xbfffffff] gap first,
then the [mem 0xe0000000-0xf7ffffff] gap.
With this patch an architecture can choose to allocate from the top gap
[mem 0xe0000000-0xf7ffffff] first.
We can't do this across the board because iomem_resource.end is initialized
to 0xffffffff_ffffffff on 64-bit architectures, and most machines can't
address the entire 64-bit physical address space. Therefore, we only
allocate top-down if the arch requests it by clearing
"resource_alloc_from_bottom".
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/ioport.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/ioport.h b/include/linux/ioport.h index b22790268b64..d377ea815d45 100644 --- a/include/linux/ioport.h +++ b/include/linux/ioport.h @@ -112,6 +112,7 @@ struct resource_list { /* PC/ISA/whatever - the normal PC address spaces: IO and memory */ extern struct resource ioport_resource; extern struct resource iomem_resource; +extern int resource_alloc_from_bottom; extern struct resource *request_resource_conflict(struct resource *root, struct resource *new); extern int request_resource(struct resource *root, struct resource *new); |