Commit 05b3cbd8 authored by Ravikiran Thirumalai's avatar Ravikiran Thirumalai Committed by Linus Torvalds
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[PATCH] x86_64: Early initialization of cpu_to_node 



Patch enables early intialization of cpu_to_node.
apicid_to_node is built by reading the SRAT table, from acpi_numa_init with
ACPI_NUMA and k8_scan_nodes with K8_NUMA.
x86_cpu_to_apicid is built by parsing the ACPI MADT table, from acpi_boot_init.
We combine these two tables and setup cpu_to_node.

Early intialization helps the static per_cpu_areas in getting pages from
correct node.

Change since last release:
Do not initialize early init_cpu_to_node for faking node cases.

Patch tested on TYAN dual core 4P board with K8 only, ACPI_NUMA.
Tested on EM64T NUMA. Also tested with numa=off, numa=fake, and  running
a kernel compiled with NUMA on a regular EM64 2 way SMP.

Signed-off-by: default avatarAlok N Kataria <alokk@calsoftinc.com>
Signed-off-by: default avatarRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: default avatarShai Fultheim <shai@scalex86.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0b91317e

arch/x86_64/kernel/setup.c

+2 −0
Original line number Diff line number Diff line
@@ -713,6 +713,8 @@ void __init setup_arch(char **cmdline_p) 
	acpi_boot_init();

#endif



	init_cpu_to_node();



#ifdef CONFIG_X86_LOCAL_APIC

	/*

	 * get boot-time SMP configuration:

arch/x86_64/mm/numa.c

+25 −0
Original line number Diff line number Diff line
@@ -330,6 +330,31 @@ __init int numa_setup(char *opt) 
	return 1;

} 



/*

 * Setup early cpu_to_node.

 *

 * Populate cpu_to_node[] only if x86_cpu_to_apicid[],

 * and apicid_to_node[] tables have valid entries for a CPU.

 * This means we skip cpu_to_node[] initialisation for NUMA

 * emulation and faking node case (when running a kernel compiled

 * for NUMA on a non NUMA box), which is OK as cpu_to_node[]

 * is already initialized in a round robin manner at numa_init_array,

 * prior to this call, and this initialization is good enough

 * for the fake NUMA cases.

 */

void __init init_cpu_to_node(void)

{

	int i;

 	for (i = 0; i < NR_CPUS; i++) {

		u8 apicid = x86_cpu_to_apicid[i];

		if (apicid == BAD_APICID)

			continue;

		if (apicid_to_node[apicid] == NUMA_NO_NODE)

			continue;

 		cpu_to_node[i] = apicid_to_node[apicid];

	}

}



EXPORT_SYMBOL(cpu_to_node);

EXPORT_SYMBOL(node_to_cpumask);

EXPORT_SYMBOL(memnode_shift);

include/asm-x86_64/numa.h

+5 −0
Original line number Diff line number Diff line
@@ -20,6 +20,11 @@ extern int numa_off; 
extern void numa_set_node(int cpu, int node);



extern unsigned char apicid_to_node[256];

#ifdef CONFIG_NUMA

extern void __init init_cpu_to_node(void);

#else

#define init_cpu_to_node() do {} while (0)

#endif



#define NUMA_NO_NODE 0xff

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