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Date: Mon, 27 Dec 2010 16:48:24 -0800
From: Yinghai Lu <yinghai@...nel.org>
To: Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
"H. Peter Anvin" <hpa@...or.com>
CC: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: [PATCH 4/6] x86: Use early pre-allocated page table buffer top-down
We pre-allocate those buffer from top, so should use it top-down, so could
return unused part will be bottom side.
Will get less one hole in not used RAM.
Signed-off-by: Yinghai Lu <yinghai@...nel.org>
---
arch/x86/include/asm/init.h | 6 +++---
arch/x86/mm/init.c | 12 ++++++------
arch/x86/mm/init_32.c | 4 ++--
arch/x86/mm/init_64.c | 5 +++--
4 files changed, 14 insertions(+), 13 deletions(-)
Index: linux-2.6/arch/x86/include/asm/init.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/init.h
+++ linux-2.6/arch/x86/include/asm/init.h
@@ -11,8 +11,8 @@ kernel_physical_mapping_init(unsigned lo
unsigned long page_size_mask);
-extern unsigned long __initdata e820_table_start;
-extern unsigned long __meminitdata e820_table_end;
-extern unsigned long __meminitdata e820_table_top;
+extern unsigned long __meminitdata e820_table_start;
+extern unsigned long __initdata e820_table_end;
+extern unsigned long __meminitdata e820_table_bottom;
#endif /* _ASM_X86_INIT_32_H */
Index: linux-2.6/arch/x86/mm/init.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init.c
+++ linux-2.6/arch/x86/mm/init.c
@@ -18,9 +18,9 @@
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
-unsigned long __initdata e820_table_start;
-unsigned long __meminitdata e820_table_end;
-unsigned long __meminitdata e820_table_top;
+unsigned long __meminitdata e820_table_start;
+unsigned long __initdata e820_table_end;
+unsigned long __meminitdata e820_table_bottom;
int after_bootmem;
@@ -73,12 +73,12 @@ static void __init find_early_table_spac
if (base == MEMBLOCK_ERROR)
panic("Cannot find space for the kernel page tables");
- e820_table_start = base >> PAGE_SHIFT;
+ e820_table_start = (base + tables) >> PAGE_SHIFT;
e820_table_end = e820_table_start;
- e820_table_top = e820_table_start + (tables >> PAGE_SHIFT);
+ e820_table_bottom = base >> PAGE_SHIFT;
printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
- end, e820_table_start << PAGE_SHIFT, e820_table_top << PAGE_SHIFT);
+ end, e820_table_bottom << PAGE_SHIFT, e820_table_end << PAGE_SHIFT);
}
struct map_range {
Index: linux-2.6/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init_32.c
+++ linux-2.6/arch/x86/mm/init_32.c
@@ -61,10 +61,10 @@ bool __read_mostly __vmalloc_start_set =
static __init void *alloc_low_page(void)
{
- unsigned long pfn = e820_table_end++;
+ unsigned long pfn = --e820_table_start;
void *adr;
- if (pfn >= e820_table_top)
+ if (pfn < e820_table_bottom)
panic("alloc_low_page: ran out of memory");
adr = __va(pfn * PAGE_SIZE);
Index: linux-2.6/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init_64.c
+++ linux-2.6/arch/x86/mm/init_64.c
@@ -314,7 +314,7 @@ void __init cleanup_highmap(void)
static __ref void *alloc_low_page(unsigned long *phys)
{
- unsigned long pfn = e820_table_end++;
+ unsigned long pfn;
void *adr;
if (after_bootmem) {
@@ -324,7 +324,8 @@ static __ref void *alloc_low_page(unsign
return adr;
}
- if (pfn >= e820_table_top)
+ pfn = --e820_table_start;
+ if (pfn < e820_table_bottom)
panic("alloc_low_page: ran out of memory");
adr = early_memremap(pfn * PAGE_SIZE, PAGE_SIZE);
--
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