path: root/Documentation/kernel-parameters.txt
diff options
authorBjorn Helgaas <bjorn.helgaas@hp.com>2010-10-26 15:41:33 -0600
committerJesse Barnes <jbarnes@virtuousgeek.org>2010-10-26 15:33:31 -0700
commite7f8567db9a7f6b3151b0b275e245c1cef0d9c70 (patch)
treef04a01581e86ec2b8c175b9f27648679c70d592c /Documentation/kernel-parameters.txt
parenta1862e31079149a52b6223776228c3aee493d4a7 (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/kernel-parameters.txt')
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