From e7f8567db9a7f6b3151b0b275e245c1cef0d9c70 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Tue, 26 Oct 2010 15:41:33 -0600 Subject: 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 Signed-off-by: Jesse Barnes --- Documentation/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 8dd7248508a9..fe50cbd315b0 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 -- cgit v1.2.3-59-g8ed1b