2008-03-19 23:20:50

by Yinghai Lu

[permalink] [raw]
Subject: [PATCH] x86: trim mtrr don't close gap for resource allocation.

[PATCH] x86: trim mtrr don't close gap for resource allocation.

for
http://bugzilla.kernel.org/show_bug.cgi?id=10232

use update_memory_range instead of add_memory_range directly
to avoid closing that gap.

Signed-off-by: Yinghai Lu <[email protected]>

Index: linux-2.6/arch/x86/kernel/cpu/mtrr/main.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/main.c
+++ linux-2.6/arch/x86/kernel/cpu/mtrr/main.c
@@ -711,7 +711,8 @@ int __init mtrr_trim_uncached_memory(uns
trim_size = end_pfn;
trim_size <<= PAGE_SHIFT;
trim_size -= trim_start;
- add_memory_region(trim_start, trim_size, E820_RESERVED);
+ update_memory_range(trim_start, trim_size, E820_RAM,
+ E820_RESERVED);
update_e820();
return 1;
}
Index: linux-2.6/arch/x86/kernel/e820_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820_32.c
+++ linux-2.6/arch/x86/kernel/e820_32.c
@@ -749,6 +749,32 @@ static int __init parse_memmap(char *arg
return 0;
}
early_param("memmap", parse_memmap);
+void __init update_memory_range(u64 start, u64 size, unsigned old_type,
+ unsigned new_type)
+{
+ int i;
+
+ BUG_ON(old_type == new_type);
+
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ u64 final_start, final_end;
+ if (ei->type != old_type)
+ continue;
+ /* totally covered? */
+ if (ei->addr >= start && ei->size <= size) {
+ ei->type = new_type;
+ continue;
+ }
+ /* partially covered */
+ final_start = max(start, ei->addr);
+ final_end = min(start + size, ei->addr + ei->size);
+ if (final_start >= final_end)
+ continue;
+ add_memory_region(final_start, final_end - final_start,
+ new_type);
+ }
+}
void __init update_e820(void)
{
u8 nr_map;
Index: linux-2.6/arch/x86/kernel/e820_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820_64.c
+++ linux-2.6/arch/x86/kernel/e820_64.c
@@ -735,6 +735,33 @@ void __init finish_e820_parsing(void)
}
}

+void __init update_memory_range(u64 start, u64 size, unsigned old_type,
+ unsigned new_type)
+{
+ int i;
+
+ BUG_ON(old_type == new_type);
+
+ for (i = 0; i < e820.nr_map; i++) {
+ struct e820entry *ei = &e820.map[i];
+ u64 final_start, final_end;
+ if (ei->type != old_type)
+ continue;
+ /* totally covered? */
+ if (ei->addr >= start && ei->size <= size) {
+ ei->type = new_type;
+ continue;
+ }
+ /* partially covered */
+ final_start = max(start, ei->addr);
+ final_end = min(start + size, ei->addr + ei->size);
+ if (final_start >= final_end)
+ continue;
+ add_memory_region(final_start, final_end - final_start,
+ new_type);
+ }
+}
+
void __init update_e820(void)
{
u8 nr_map;
Index: linux-2.6/include/asm-x86/e820_32.h
===================================================================
--- linux-2.6.orig/include/asm-x86/e820_32.h
+++ linux-2.6/include/asm-x86/e820_32.h
@@ -28,6 +28,8 @@ extern void find_max_pfn(void);
extern void register_bootmem_low_pages(unsigned long max_low_pfn);
extern void add_memory_region(unsigned long long start,
unsigned long long size, int type);
+extern void update_memory_range(u64 start, u64 size, unsigned old_type,
+ unsigned new_type);
extern void e820_register_memory(void);
extern void limit_regions(unsigned long long size);
extern void print_memory_map(char *who);
Index: linux-2.6/include/asm-x86/e820_64.h
===================================================================
--- linux-2.6.orig/include/asm-x86/e820_64.h
+++ linux-2.6/include/asm-x86/e820_64.h
@@ -18,6 +18,8 @@ extern unsigned long find_e820_area(unsi
unsigned long size, unsigned long align);
extern void add_memory_region(unsigned long start, unsigned long size,
int type);
+extern void update_memory_range(u64 start, u64 size, unsigned old_type,
+ unsigned new_type);
extern void setup_memory_region(void);
extern void contig_e820_setup(void);
extern unsigned long e820_end_of_ram(void);


2008-03-21 10:44:27

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH] x86: trim mtrr don't close gap for resource allocation.


* Yinghai Lu <[email protected]> wrote:

> [PATCH] x86: trim mtrr don't close gap for resource allocation.
>
> for
> http://bugzilla.kernel.org/show_bug.cgi?id=10232
>
> use update_memory_range instead of add_memory_range directly to avoid
> closing that gap.

thanks Yinghai, applied, and queued up for 2.6.25.

Ingo