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memory hotplug: fix a bug on /dev/mem for 64-bit kernels 

Newly added memory can not be accessed via /dev/mem, because we do not
update the variables high_memory, max_pfn and max_low_pfn.

Add a function update_end_of_memory_vars() to update these variables for
64-bit kernels.

[akpm@linux-foundation.org: simplify comment]
Signed-off-by: Shaohui Zheng <shaohui.zheng@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Li Haicheng <haicheng.li@intel.com>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Shaohui Zheng 2010-02-02 13:44:16 -08:00 committed by Linus Torvalds
parent a225a5cc2c
commit ea0854170c
1 changed files with 19 additions and 0 deletions
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19
arch/x86/mm/init_64.c
View File

@ -49,6 +49,7 @@
#include <asm/numa.h>
#include <asm/cacheflush.h>
#include <asm/init.h>
#include <linux/bootmem.h>
static unsigned long dma_reserve __initdata;
@ -615,6 +616,21 @@ void __init paging_init(void)
* Memory hotplug specific functions
*/
#ifdef CONFIG_MEMORY_HOTPLUG
/*
* After memory hotplug the variables max_pfn, max_low_pfn and high_memory need
* updating.
*/
static void update_end_of_memory_vars(u64 start, u64 size)
{
unsigned long end_pfn = PFN_UP(start + size);
if (end_pfn > max_pfn) {
max_pfn = end_pfn;
max_low_pfn = end_pfn;
high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
}
}
/*
* Memory is added always to NORMAL zone. This means you will never get
* additional DMA/DMA32 memory.
@ -634,6 +650,9 @@ int arch_add_memory(int nid, u64 start, u64 size)
ret = __add_pages(nid, zone, start_pfn, nr_pages);
WARN_ON_ONCE(ret);
/* update max_pfn, max_low_pfn and high_memory */
update_end_of_memory_vars(start, size);
return ret;
}
EXPORT_SYMBOL_GPL(arch_add_memory);