On Sat, 18 Apr 2009, Yinghai Lu wrote:
>
> except need to change
> > + reserve_region_with_split(&iomem_resource, start, end, "RAM buffer");
> ==> > + reserve_region_with_split(&iomem_resource, start, end - 1, "RAM buffer");
Yes, I sent out a later email pointing that out.
> it will make sure dynmical allocating code will not use those range.
>
> and could make e820_setup_gap much simple.
ACK. In fact:
> Index: linux-2.6/arch/x86/kernel/e820.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/e820.c
> +++ linux-2.6/arch/x86/kernel/e820.c
> @@ -635,14 +635,12 @@ __init void e820_setup_gap(void)
> #endif
>
> /*
> - * See how much we want to round up: start off with
> - * rounding to the next 1MB area.
> + * e820_reserve_resources_late will protect stolen RAM
> + * so just round it to 1M
> */
> round = 0x100000;
> - while ((gapsize >> 4) > round)
> - round += round;
> - /* Fun with two's complement */
> - pci_mem_start = (gapstart + round) & -round;
> +
> + pci_mem_start = roundup(gapstart, round);
You can just remove "round" entirely. It's no longer a variable, it's just
an odd way of saying 1M ;)
> Ingo, can you put those two patches in tip?
I would suggest that we first change "reserve_region_with_split()" to not
recurse into the region.
That function isn't used by anything else (we ended up using
"expand_to_fit()" instead in the one place that migth have used it), and
now th eone caller we do have would not want the recursion - if there
already exists a resource at the top level, we want to just avoid it.
This - again TOTALLY UNTESTED - patch removes the "recurse into conflicts"
code. Comments? Testing?
Linus
---
kernel/resource.c | 46 ++++++++++++----------------------------------
1 files changed, 12 insertions(+), 34 deletions(-)
diff --git a/kernel/resource.c b/kernel/resource.c
index fd5d7d5..ac5f3a3 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -533,43 +533,21 @@ static void __init __reserve_region_with_split(struct resource *root,
res->end = end;
res->flags = IORESOURCE_BUSY;
- for (;;) {
- conflict = __request_resource(parent, res);
- if (!conflict)
- break;
- if (conflict != parent) {
- parent = conflict;
- if (!(conflict->flags & IORESOURCE_BUSY))
- continue;
- }
-
- /* Uhhuh, that didn't work out.. */
- kfree(res);
- res = NULL;
- break;
- }
-
- if (!res) {
- /* failed, split and try again */
-
- /* conflict covered whole area */
- if (conflict->start <= start && conflict->end >= end)
- return;
+ conflict = __request_resource(parent, res);
+ if (!conflict)
+ return;
- if (conflict->start > start)
- __reserve_region_with_split(root, start, conflict->start-1, name);
- if (!(conflict->flags & IORESOURCE_BUSY)) {
- resource_size_t common_start, common_end;
+ /* failed, split and try again */
+ kfree(res);
- common_start = max(conflict->start, start);
- common_end = min(conflict->end, end);
- if (common_start < common_end)
- __reserve_region_with_split(root, common_start, common_end, name);
- }
- if (conflict->end < end)
- __reserve_region_with_split(root, conflict->end+1, end, name);
- }
+ /* conflict covered whole area */
+ if (conflict->start <= start && conflict->end >= end)
+ return;
+ if (conflict->start > start)
+ __reserve_region_with_split(root, start, conflict->start-1, name);
+ if (conflict->end < end)
+ __reserve_region_with_split(root, conflict->end+1, end, name);
}
void __init reserve_region_with_split(struct resource *root,
--
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