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Commit 72812019 authored by Lee Schermerhorn's avatar Lee Schermerhorn Committed by Linus Torvalds
Browse files

numa: add generic percpu var numa_node_id() implementation 



Rework the generic version of the numa_node_id() function to use the new
generic percpu variable infrastructure.

Guard the new implementation with a new config option:

        CONFIG_USE_PERCPU_NUMA_NODE_ID.

Archs which support this new implemention will default this option to 'y'
when NUMA is configured.  This config option could be removed if/when all
archs switch over to the generic percpu implementation of numa_node_id().
Arch support involves:

  1) converting any existing per cpu variable implementations to use
     this implementation.  x86_64 is an instance of such an arch.
  2) archs that don't use a per cpu variable for numa_node_id() will
     need to initialize the new per cpu variable "numa_node" as cpus
     are brought on-line.  ia64 is an example.
  3) Defining USE_PERCPU_NUMA_NODE_ID in arch dependent Kconfig--e.g.,
     when NUMA is configured.  This is required because I have
     retained the old implementation by default to allow archs to
     be modified incrementally, as desired.

Subsequent patches will convert x86_64 and ia64 to use this implemenation.

Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: default avatarChristoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: 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>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 866707fc

arch/x86/include/asm/topology.h

+4 −0
Original line number Diff line number Diff line
@@ -170,6 +170,10 @@ static inline int numa_node_id(void) 
{

	return 0;

}

/*

 * indicate override:

 */

#define numa_node_id numa_node_id



static inline int early_cpu_to_node(int cpu)

{

include/linux/topology.h

+46 −5
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/bitops.h>

#include <linux/mmzone.h>

#include <linux/smp.h>

#include <linux/percpu.h>

#include <asm/topology.h>



#ifndef node_has_online_mem
@@ -203,8 +204,53 @@ int arch_update_cpu_topology(void); 
#ifndef SD_NODE_INIT

#error Please define an appropriate SD_NODE_INIT in include/asm/topology.h!!!

#endif



#endif /* CONFIG_NUMA */



#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID

DECLARE_PER_CPU(int, numa_node);



#ifndef numa_node_id

/* Returns the number of the current Node. */

static inline int numa_node_id(void)

{

	return __this_cpu_read(numa_node);

}

#endif



#ifndef cpu_to_node

static inline int cpu_to_node(int cpu)

{

	return per_cpu(numa_node, cpu);

}

#endif



#ifndef set_numa_node

static inline void set_numa_node(int node)

{

	percpu_write(numa_node, node);

}

#endif



#ifndef set_cpu_numa_node

static inline void set_cpu_numa_node(int cpu, int node)

{

	per_cpu(numa_node, cpu) = node;

}

#endif



#else	/* !CONFIG_USE_PERCPU_NUMA_NODE_ID */



/* Returns the number of the current Node. */

#ifndef numa_node_id

static inline int numa_node_id(void)

{

	return cpu_to_node(raw_smp_processor_id());

}

#endif



#endif	/* [!]CONFIG_USE_PERCPU_NUMA_NODE_ID */



#ifndef topology_physical_package_id

#define topology_physical_package_id(cpu)	((void)(cpu), -1)

#endif
@@ -218,9 +264,4 @@ int arch_update_cpu_topology(void); 
#define topology_core_cpumask(cpu)		cpumask_of(cpu)

#endif



/* Returns the number of the current Node. */

#ifndef numa_node_id

#define numa_node_id()		(cpu_to_node(raw_smp_processor_id()))

#endif



#endif /* _LINUX_TOPOLOGY_H */

mm/page_alloc.c

+5 −0
Original line number Diff line number Diff line
@@ -57,6 +57,11 @@ 
#include <asm/div64.h>

#include "internal.h"



#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID

DEFINE_PER_CPU(int, numa_node);

EXPORT_PER_CPU_SYMBOL(numa_node);

#endif



/*

 * Array of node states.

 */