[PATCH] x86: keep the page count correct

From: Yinghai Lu
Date: Sun Oct 26 2008 - 02:00:03 EST



impact: get correct page count for 2M and 1G...

found page count in /proc/meminfo is nor correct on 1G system in VirtualBox 2.0.4

# cat /proc/meminfo
MemTotal: 1017508 kB
MemFree: 822700 kB
Buffers: 1456 kB
Cached: 26632 kB
SwapCached: 0 kB
...
Hugepagesize: 2048 kB
DirectMap4k: 4032 kB
DirectMap2M: 18446744073709549568 kB

with this patch get:
...
DirectMap4k: 4032 kB
DirectMap2M: 1044480 kB

which is consistent to kernel_page_tables
---[ Low Kernel Mapping ]---
0xffff880000000000-0xffff880000001000 4K RW PCD GLB x pte
0xffff880000001000-0xffff88000009f000 632K RW GLB x pte
0xffff88000009f000-0xffff8800000a0000 4K RW PCD GLB x pte
0xffff8800000a0000-0xffff880000200000 1408K RW GLB x pte
0xffff880000200000-0xffff88003fe00000 1020M RW PSE GLB x pmd
0xffff88003fe00000-0xffff88003fff0000 1984K RW GLB NX pte
0xffff88003fff0000-0xffff880040000000 64K pte
0xffff880040000000-0xffff888000000000 511G pud
0xffff888000000000-0xffffc20000000000 58880G pgd

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 7df1209..701675a 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -350,8 +350,10 @@ phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end,
* pagetable pages as RO. So assume someone who pre-setup
* these mappings are more intelligent.
*/
- if (pte_val(*pte))
+ if (pte_val(*pte)) {
+ pages++;
continue;
+ }

if (0)
printk(" pte=%p addr=%lx pte=%016lx\n",
@@ -418,8 +420,10 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
* not differ with respect to page frame and
* attributes.
*/
- if (page_size_mask & (1 << PG_LEVEL_2M))
+ if (page_size_mask & (1 << PG_LEVEL_2M)) {
+ pages++;
continue;
+ }
new_prot = pte_pgprot(pte_clrhuge(*(pte_t *)pmd));
}

@@ -499,8 +503,10 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
* not differ with respect to page frame and
* attributes.
*/
- if (page_size_mask & (1 << PG_LEVEL_1G))
+ if (page_size_mask & (1 << PG_LEVEL_1G)) {
+ pages++;
continue;
+ }
prot = pte_pgprot(pte_clrhuge(*(pte_t *)pud));
}

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