From 68a3a7feb08f960095072f28ec20f7900793c506 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Fri, 7 Apr 2006 19:49:18 +0200 Subject: [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 : 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 Signed-off-by: Linus Torvalds --- include/asm-x86_64/numa.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/asm-x86_64/numa.h b/include/asm-x86_64/numa.h index f6cbb4cbb5a3..f0ba4d984bdf 100644 --- a/include/asm-x86_64/numa.h +++ b/include/asm-x86_64/numa.h @@ -18,6 +18,8 @@ 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 -- cgit v1.2.3