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Subject[1/8,v3] NUMA Hotplug Emulator: add function to hide memory region via e820 table.
From: Haicheng Li <haicheng.li@intel.com>

NUMA hotplug emulator needs to hide memory regions at the very
beginning of kernel booting. Then emulator will use these
memory regions to fake offlined numa nodes.

CC: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Haicheng Li <haicheng.li@intel.com>
Signed-off-by: Shaohui Zheng <shaohui.zheng@intel.com>
---
arch/x86/include/asm/e820.h | 1 +
arch/x86/kernel/e820.c | 19 ++++++++++++++++++-
2 files changed, 19 insertions(+), 1 deletions(-)

Index: linux-hpe4/arch/x86/include/asm/e820.h
===================================================================
--- linux-hpe4.orig/arch/x86/include/asm/e820.h 2010-11-15 17:13:02.483461667 +0800
+++ linux-hpe4/arch/x86/include/asm/e820.h 2010-11-15 17:13:07.083461581 +0800
@@ -129,6 +129,7 @@
extern void e820_register_active_regions(int nid, unsigned long start_pfn,
unsigned long end_pfn);
extern u64 e820_hole_size(u64 start, u64 end);
+extern u64 e820_hide_mem(u64 mem_size);
extern void finish_e820_parsing(void);
extern void e820_reserve_resources(void);
extern void e820_reserve_resources_late(void);
Index: linux-hpe4/arch/x86/kernel/e820.c
===================================================================
--- linux-hpe4.orig/arch/x86/kernel/e820.c 2010-11-15 17:13:02.483461667 +0800
+++ linux-hpe4/arch/x86/kernel/e820.c 2010-11-15 17:13:07.083461581 +0800
@@ -971,6 +971,7 @@
}

static int userdef __initdata;
+static u64 max_mem_size __initdata = ULLONG_MAX;

/* "mem=nopentium" disables the 4MB page tables. */
static int __init parse_memopt(char *p)
@@ -989,12 +990,28 @@

userdef = 1;
mem_size = memparse(p, &p);
- e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
+ e820_remove_range(mem_size, max_mem_size - mem_size, E820_RAM, 1);
+ max_mem_size = mem_size;

return 0;
}
early_param("mem", parse_memopt);

+#ifdef CONFIG_NODE_HOTPLUG_EMU
+u64 __init e820_hide_mem(u64 mem_size)
+{
+ u64 start, end_pfn;
+
+ userdef = 1;
+ end_pfn = e820_end_of_ram_pfn();
+ start = (end_pfn << PAGE_SHIFT) - mem_size;
+ e820_remove_range(start, max_mem_size - start, E820_RAM, 1);
+ max_mem_size = start;
+
+ return start;
+}
+#endif
+
static int __init parse_memmap_opt(char *p)
{
char *oldp;
--
Thanks & Regards,
Shaohui




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