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| author | Bjorn Helgaas <bjorn.helgaas@hp.com> | 2010-10-26 15:41:33 -0600 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-10-26 15:33:31 -0700 |
| commit | e7f8567db9a7f6b3151b0b275e245c1cef0d9c70 (patch) | |
| tree | f04a01581e86ec2b8c175b9f27648679c70d592c /Documentation | |
| parent | a1862e31079149a52b6223776228c3aee493d4a7 (diff) | |
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 'Documentation')
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8dd7248508a..fe50cbd315b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2156,6 +2156,11 @@ and is between 256 and 4096 characters. It is defined in the file reset_devices [KNL] Force drivers to reset the underlying device during initialization. + resource_alloc_from_bottom + Allocate new resources from the beginning of available + space, not the end. If you need to use this, please + report a bug. + resume= [SWSUSP] Specify the partition device for software suspend |