470fd64644
When a cpu is disabled, move_task_off_dead_cpu() is called for tasks that have
been running on that cpu.
Currently, such a task is migrated:
1) to any cpu on the same node as the disabled cpu, which is both online
and among that task's cpus_allowed
2) to any cpu which is both online and among that task's cpus_allowed
It is typical of a multithreaded application running on a large NUMA system to
have its tasks confined to a cpuset so as to cluster them near the memory that
they share. Furthermore, it is typical to explicitly place such a task on a
specific cpu in that cpuset. And in that case the task's cpus_allowed
includes only a single cpu.
This patch would insert a preference to migrate such a task to some cpu within
its cpuset (and set its cpus_allowed to its entire cpuset).
With this patch, migrate the task to:
1) to any cpu on the same node as the disabled cpu, which is both online
and among that task's cpus_allowed
2) to any online cpu within the task's cpuset
3) to any cpu which is both online and among that task's cpus_allowed
In order to do this, move_task_off_dead_cpu() must make a call to
cpuset_cpus_allowed_locked(), a new subset of cpuset_cpus_allowed(), that will
not block. (name change - per Oleg's suggestion)
Calls are made to cpuset_lock() and cpuset_unlock() in migration_call() to set
the cpuset mutex during the whole migrate_live_tasks() and
migrate_dead_tasks() procedure.
[akpm@linux-foundation.org: build fix]
[pj@sgi.com: Fix indentation and spacing]
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
163 lines
4 KiB
C
163 lines
4 KiB
C
#ifndef _LINUX_CPUSET_H
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#define _LINUX_CPUSET_H
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/*
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* cpuset interface
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*
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* Copyright (C) 2003 BULL SA
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* Copyright (C) 2004-2006 Silicon Graphics, Inc.
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*
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*/
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#include <linux/sched.h>
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#include <linux/cpumask.h>
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#include <linux/nodemask.h>
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#include <linux/cgroup.h>
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#ifdef CONFIG_CPUSETS
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extern int number_of_cpusets; /* How many cpusets are defined in system? */
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extern int cpuset_init_early(void);
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extern int cpuset_init(void);
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extern void cpuset_init_smp(void);
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extern cpumask_t cpuset_cpus_allowed(struct task_struct *p);
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extern cpumask_t cpuset_cpus_allowed_locked(struct task_struct *p);
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extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
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#define cpuset_current_mems_allowed (current->mems_allowed)
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void cpuset_init_current_mems_allowed(void);
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void cpuset_update_task_memory_state(void);
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#define cpuset_nodes_subset_current_mems_allowed(nodes) \
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nodes_subset((nodes), current->mems_allowed)
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int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl);
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extern int __cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask);
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extern int __cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask);
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static int inline cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
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{
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return number_of_cpusets <= 1 ||
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__cpuset_zone_allowed_softwall(z, gfp_mask);
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}
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static int inline cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
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{
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return number_of_cpusets <= 1 ||
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__cpuset_zone_allowed_hardwall(z, gfp_mask);
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}
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extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
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const struct task_struct *tsk2);
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#define cpuset_memory_pressure_bump() \
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do { \
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if (cpuset_memory_pressure_enabled) \
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__cpuset_memory_pressure_bump(); \
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} while (0)
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extern int cpuset_memory_pressure_enabled;
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extern void __cpuset_memory_pressure_bump(void);
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extern const struct file_operations proc_cpuset_operations;
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extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer);
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extern void cpuset_lock(void);
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extern void cpuset_unlock(void);
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extern int cpuset_mem_spread_node(void);
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static inline int cpuset_do_page_mem_spread(void)
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{
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return current->flags & PF_SPREAD_PAGE;
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}
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static inline int cpuset_do_slab_mem_spread(void)
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{
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return current->flags & PF_SPREAD_SLAB;
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}
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extern void cpuset_track_online_nodes(void);
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extern int current_cpuset_is_being_rebound(void);
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#else /* !CONFIG_CPUSETS */
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static inline int cpuset_init_early(void) { return 0; }
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static inline int cpuset_init(void) { return 0; }
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static inline void cpuset_init_smp(void) {}
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static inline cpumask_t cpuset_cpus_allowed(struct task_struct *p)
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{
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return cpu_possible_map;
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}
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static inline cpumask_t cpuset_cpus_allowed_locked(struct task_struct *p)
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{
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return cpu_possible_map;
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}
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static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
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{
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return node_possible_map;
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}
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#define cpuset_current_mems_allowed (node_states[N_HIGH_MEMORY])
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static inline void cpuset_init_current_mems_allowed(void) {}
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static inline void cpuset_update_task_memory_state(void) {}
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#define cpuset_nodes_subset_current_mems_allowed(nodes) (1)
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static inline int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
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{
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return 1;
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}
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static inline int cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
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{
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return 1;
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}
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static inline int cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
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{
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return 1;
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}
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static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
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const struct task_struct *tsk2)
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{
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return 1;
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}
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static inline void cpuset_memory_pressure_bump(void) {}
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static inline char *cpuset_task_status_allowed(struct task_struct *task,
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char *buffer)
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{
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return buffer;
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}
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static inline void cpuset_lock(void) {}
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static inline void cpuset_unlock(void) {}
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static inline int cpuset_mem_spread_node(void)
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{
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return 0;
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}
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static inline int cpuset_do_page_mem_spread(void)
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{
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return 0;
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}
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static inline int cpuset_do_slab_mem_spread(void)
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{
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return 0;
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}
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static inline void cpuset_track_online_nodes(void) {}
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static inline int current_cpuset_is_being_rebound(void)
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{
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return 0;
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}
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#endif /* !CONFIG_CPUSETS */
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#endif /* _LINUX_CPUSET_H */
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