linux/include/linux/cpuset.h
Oleg Nesterov 9084bb8246 sched: Make select_fallback_rq() cpuset friendly
Introduce cpuset_cpus_allowed_fallback() helper to fix the cpuset problems
with select_fallback_rq(). It can be called from any context and can't use
any cpuset locks including task_lock(). It is called when the task doesn't
have online cpus in ->cpus_allowed but ttwu/etc must be able to find a
suitable cpu.

I am not proud of this patch. Everything which needs such a fat comment
can't be good even if correct. But I'd prefer to not change the locking
rules in the code I hardly understand, and in any case I believe this
simple change make the code much more correct compared to deadlocks we
currently have.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100315091027.GA9155@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-04-02 20:12:03 +02:00

193 lines
4.5 KiB
C

#ifndef _LINUX_CPUSET_H
#define _LINUX_CPUSET_H
/*
* cpuset interface
*
* Copyright (C) 2003 BULL SA
* Copyright (C) 2004-2006 Silicon Graphics, Inc.
*
*/
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#include <linux/cgroup.h>
#include <linux/mm.h>
#ifdef CONFIG_CPUSETS
extern int number_of_cpusets; /* How many cpusets are defined in system? */
extern int cpuset_init(void);
extern void cpuset_init_smp(void);
extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
extern int cpuset_cpus_allowed_fallback(struct task_struct *p);
extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
#define cpuset_current_mems_allowed (current->mems_allowed)
void cpuset_init_current_mems_allowed(void);
int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask);
extern int __cpuset_node_allowed_softwall(int node, gfp_t gfp_mask);
extern int __cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask);
static inline int cpuset_node_allowed_softwall(int node, gfp_t gfp_mask)
{
return number_of_cpusets <= 1 ||
__cpuset_node_allowed_softwall(node, gfp_mask);
}
static inline int cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask)
{
return number_of_cpusets <= 1 ||
__cpuset_node_allowed_hardwall(node, gfp_mask);
}
static inline int cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
{
return cpuset_node_allowed_softwall(zone_to_nid(z), gfp_mask);
}
static inline int cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
{
return cpuset_node_allowed_hardwall(zone_to_nid(z), gfp_mask);
}
extern int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
const struct task_struct *tsk2);
#define cpuset_memory_pressure_bump() \
do { \
if (cpuset_memory_pressure_enabled) \
__cpuset_memory_pressure_bump(); \
} while (0)
extern int cpuset_memory_pressure_enabled;
extern void __cpuset_memory_pressure_bump(void);
extern const struct file_operations proc_cpuset_operations;
struct seq_file;
extern void cpuset_task_status_allowed(struct seq_file *m,
struct task_struct *task);
extern int cpuset_mem_spread_node(void);
static inline int cpuset_do_page_mem_spread(void)
{
return current->flags & PF_SPREAD_PAGE;
}
static inline int cpuset_do_slab_mem_spread(void)
{
return current->flags & PF_SPREAD_SLAB;
}
extern int current_cpuset_is_being_rebound(void);
extern void rebuild_sched_domains(void);
extern void cpuset_print_task_mems_allowed(struct task_struct *p);
static inline void set_mems_allowed(nodemask_t nodemask)
{
current->mems_allowed = nodemask;
}
#else /* !CONFIG_CPUSETS */
static inline int cpuset_init(void) { return 0; }
static inline void cpuset_init_smp(void) {}
static inline void cpuset_cpus_allowed(struct task_struct *p,
struct cpumask *mask)
{
cpumask_copy(mask, cpu_possible_mask);
}
static inline int cpuset_cpus_allowed_fallback(struct task_struct *p)
{
cpumask_copy(&p->cpus_allowed, cpu_possible_mask);
return cpumask_any(cpu_active_mask);
}
static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
{
return node_possible_map;
}
#define cpuset_current_mems_allowed (node_states[N_HIGH_MEMORY])
static inline void cpuset_init_current_mems_allowed(void) {}
static inline int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
{
return 1;
}
static inline int cpuset_node_allowed_softwall(int node, gfp_t gfp_mask)
{
return 1;
}
static inline int cpuset_node_allowed_hardwall(int node, gfp_t gfp_mask)
{
return 1;
}
static inline int cpuset_zone_allowed_softwall(struct zone *z, gfp_t gfp_mask)
{
return 1;
}
static inline int cpuset_zone_allowed_hardwall(struct zone *z, gfp_t gfp_mask)
{
return 1;
}
static inline int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
const struct task_struct *tsk2)
{
return 1;
}
static inline void cpuset_memory_pressure_bump(void) {}
static inline void cpuset_task_status_allowed(struct seq_file *m,
struct task_struct *task)
{
}
static inline int cpuset_mem_spread_node(void)
{
return 0;
}
static inline int cpuset_do_page_mem_spread(void)
{
return 0;
}
static inline int cpuset_do_slab_mem_spread(void)
{
return 0;
}
static inline int current_cpuset_is_being_rebound(void)
{
return 0;
}
static inline void rebuild_sched_domains(void)
{
partition_sched_domains(1, NULL, NULL);
}
static inline void cpuset_print_task_mems_allowed(struct task_struct *p)
{
}
static inline void set_mems_allowed(nodemask_t nodemask)
{
}
#endif /* !CONFIG_CPUSETS */
#endif /* _LINUX_CPUSET_H */