mirror_ubuntu-kernels/arch/powerpc/include/asm/topology.h
Mel Gorman 4f9b16a647 mm: disable zone_reclaim_mode by default
When it was introduced, zone_reclaim_mode made sense as NUMA distances
punished and workloads were generally partitioned to fit into a NUMA
node.  NUMA machines are now common but few of the workloads are
NUMA-aware and it's routine to see major performance degradation due to
zone_reclaim_mode being enabled but relatively few can identify the
problem.

Those that require zone_reclaim_mode are likely to be able to detect
when it needs to be enabled and tune appropriately so lets have a
sensible default for the bulk of users.

This patch (of 2):

zone_reclaim_mode causes processes to prefer reclaiming memory from
local node instead of spilling over to other nodes.  This made sense
initially when NUMA machines were almost exclusively HPC and the
workload was partitioned into nodes.  The NUMA penalties were
sufficiently high to justify reclaiming the memory.  On current machines
and workloads it is often the case that zone_reclaim_mode destroys
performance but not all users know how to detect this.  Favour the
common case and disable it by default.  Users that are sophisticated
enough to know they need zone_reclaim_mode will detect it.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:53:59 -07:00

111 lines
2.4 KiB
C

#ifndef _ASM_POWERPC_TOPOLOGY_H
#define _ASM_POWERPC_TOPOLOGY_H
#ifdef __KERNEL__
struct device;
struct device_node;
#ifdef CONFIG_NUMA
/*
* If zone_reclaim_mode is enabled, a RECLAIM_DISTANCE of 10 will mean that
* all zones on all nodes will be eligible for zone_reclaim().
*/
#define RECLAIM_DISTANCE 10
#include <asm/mmzone.h>
static inline int cpu_to_node(int cpu)
{
int nid;
nid = numa_cpu_lookup_table[cpu];
/*
* During early boot, the numa-cpu lookup table might not have been
* setup for all CPUs yet. In such cases, default to node 0.
*/
return (nid < 0) ? 0 : nid;
}
#define parent_node(node) (node)
#define cpumask_of_node(node) ((node) == -1 ? \
cpu_all_mask : \
node_to_cpumask_map[node])
struct pci_bus;
#ifdef CONFIG_PCI
extern int pcibus_to_node(struct pci_bus *bus);
#else
static inline int pcibus_to_node(struct pci_bus *bus)
{
return -1;
}
#endif
#define cpumask_of_pcibus(bus) (pcibus_to_node(bus) == -1 ? \
cpu_all_mask : \
cpumask_of_node(pcibus_to_node(bus)))
extern int __node_distance(int, int);
#define node_distance(a, b) __node_distance(a, b)
extern void __init dump_numa_cpu_topology(void);
extern int sysfs_add_device_to_node(struct device *dev, int nid);
extern void sysfs_remove_device_from_node(struct device *dev, int nid);
#else
static inline void dump_numa_cpu_topology(void) {}
static inline int sysfs_add_device_to_node(struct device *dev, int nid)
{
return 0;
}
static inline void sysfs_remove_device_from_node(struct device *dev,
int nid)
{
}
#endif /* CONFIG_NUMA */
#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
extern int start_topology_update(void);
extern int stop_topology_update(void);
extern int prrn_is_enabled(void);
#else
static inline int start_topology_update(void)
{
return 0;
}
static inline int stop_topology_update(void)
{
return 0;
}
static inline int prrn_is_enabled(void)
{
return 0;
}
#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
#include <asm-generic/topology.h>
#ifdef CONFIG_SMP
#include <asm/cputable.h>
#ifdef CONFIG_PPC64
#include <asm/smp.h>
#define topology_physical_package_id(cpu) (cpu_to_chip_id(cpu))
#define topology_thread_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu))
#define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu))
#define topology_core_id(cpu) (cpu_to_core_id(cpu))
#endif
#endif
#endif /* __KERNEL__ */
#endif /* _ASM_POWERPC_TOPOLOGY_H */