Re: [PATCH] Optimize the resource overlap check

[Richard Yang <weiyang@linux.vnet.ibm.com>]

Bjorn,

How do you think of my this version?

On Thu, Apr 26, 2012 at 03:32:55PM +0800, Wei Yang wrote:
>In coalesce_windows() it tries to check whether the res1 and res2 overlap.
>This function do four comparisons, which could be done with one
>comparisons.
>
>Also make the resource_overlaps() a common function for others.
>
>Signed-Off-By: Wei Yang <weiyang@linux.vnet.ibm.com>
>---
> arch/x86/pci/acpi.c    |   12 +-----------
> include/linux/ioport.h |    7 +++++++
> 2 files changed, 8 insertions(+), 11 deletions(-)
>
>diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
>index 68c3c13..fd3f541 100644
>--- a/arch/x86/pci/acpi.c
>+++ b/arch/x86/pci/acpi.c
>@@ -181,13 +181,6 @@ setup_resource(struct acpi_resource *acpi_res, void *data)
> 	return AE_OK;
> }
>
>-static bool resource_contains(struct resource *res, resource_size_t point)
>-{
>-	if (res->start <= point && point <= res->end)
>-		return true;
>-	return false;
>-}
>-
> static void coalesce_windows(struct pci_root_info *info, unsigned long type)
> {
> 	int i, j;
>@@ -208,10 +201,7 @@ static void coalesce_windows(struct pci_root_info *info, unsigned long type)
> 			 * our resources no longer match the ACPI _CRS, but
> 			 * the kernel resource tree doesn't allow overlaps.
> 			 */
>-			if (resource_contains(res1, res2->start) ||
>-			    resource_contains(res1, res2->end) ||
>-			    resource_contains(res2, res1->start) ||
>-			    resource_contains(res2, res1->end)) {
>+			if (resource_overlaps(res1, res2)) {
> 				res1->start = min(res1->start, res2->start);
> 				res1->end = max(res1->end, res2->end);
> 				dev_info(&info->bridge->dev,
>diff --git a/include/linux/ioport.h b/include/linux/ioport.h
>index e9bb22c..05d2c70 100644
>--- a/include/linux/ioport.h
>+++ b/include/linux/ioport.h
>@@ -198,5 +198,12 @@ extern int
> walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
> 		void *arg, int (*func)(unsigned long, unsigned long, void *));
>
>+static inline bool resource_overlaps(struct resource *r1,
>+                                         struct resource *r2)
>+{
>+       return (r1->start <= r2->end && r1->end >= r2->start);
>+}
>+
>+
> #endif /* __ASSEMBLY__ */
> #endif	/* _LINUX_IOPORT_H */
>-- 
>1.7.4.1

-- 
Richard Yang
Help you, Help me