linux/include/asm-x86_64/numa.h
Andi Kleen 68a3a7feb0 [PATCH] x86_64: Reserve SRAT hotadd memory on x86-64
From: Keith Mannthey, Andi Kleen

Implement memory hotadd without sparsemem. The memory in the SRAT
hotadd area is just preserved instead and can be activated later.

There are a few restrictions:
- Only one continuous hotadd area allowed per node

The main problem is dealing with the many buggy SRAT tables
that are out there. The strategy here is to reject anything
suspicious.

Originally from Keith Mannthey, with several hacks and changes by AK
and also contributions from Andrew Morton

[ TBD: Problems pointed out by KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>:

 1) Goto's rebuild_zonelist patch will not work if CONFIG_MEMORY_HOTPLUG=n.

    Rebuilding zonelist is necessary when the system has just memory <
    4G at boot, and hot add memory > 4G.  because x86_64 has DMA32,
    ZONE_NORAML is not included into zonelist at boot time if system
    doesn't have memory >4G at boot.

    [AK: should just force the higher zones at boot time when SRAT tells us]

 2) zone and node's spanned_pages and present_pages are not incremented.
    They should be.

    For example, our server (ia64/Fujitsu PrimeQuest) can equip memory
    from 4G to 1T(maybe 2T in future), and SRAT will *always* say we have
    possible 1T +memory.  (Microsoft requires "write all possible memory
    in SRAT") When we reserve memmap for possible 1T memory, Linux will
    not work well in +minimum 4G configuraion ;)

    [AK: needs limiting to 5-10% of max memory]
 ]

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-09 11:53:16 -07:00

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C

#ifndef _ASM_X8664_NUMA_H
#define _ASM_X8664_NUMA_H 1
#include <linux/nodemask.h>
#include <asm/numnodes.h>
struct bootnode {
u64 start,end;
};
extern int compute_hash_shift(struct bootnode *nodes, int numnodes);
extern int pxm_to_node(int nid);
#define ZONE_ALIGN (1UL << (MAX_ORDER+PAGE_SHIFT))
extern void numa_add_cpu(int cpu);
extern void numa_init_array(void);
extern int numa_off;
extern void numa_set_node(int cpu, int node);
extern void srat_reserve_add_area(int nodeid);
extern int hotadd_percent;
extern unsigned char apicid_to_node[256];
#ifdef CONFIG_NUMA
extern void __init init_cpu_to_node(void);
static inline void clear_node_cpumask(int cpu)
{
clear_bit(cpu, &node_to_cpumask[cpu_to_node(cpu)]);
}
#else
#define init_cpu_to_node() do {} while (0)
#define clear_node_cpumask(cpu) do {} while (0)
#endif
#define NUMA_NO_NODE 0xff
#endif