android_kernel_motorola_sm6225/include/linux/cpuset.h
Paul Jackson 505970b96e [PATCH] cpuset oom lock fix
The problem, reported in:

  http://bugzilla.kernel.org/show_bug.cgi?id=5859

and by various other email messages and lkml posts is that the cpuset hook
in the oom (out of memory) code can try to take a cpuset semaphore while
holding the tasklist_lock (a spinlock).

One must not sleep while holding a spinlock.

The fix seems easy enough - move the cpuset semaphore region outside the
tasklist_lock region.

This required a few lines of mechanism to implement.  The oom code where
the locking needs to be changed does not have access to the cpuset locks,
which are internal to kernel/cpuset.c only.  So I provided a couple more
cpuset interface routines, available to the rest of the kernel, which
simple take and drop the lock needed here (cpusets callback_sem).

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-14 18:27:10 -08:00

104 lines
2.8 KiB
C

#ifndef _LINUX_CPUSET_H
#define _LINUX_CPUSET_H
/*
* cpuset interface
*
* Copyright (C) 2003 BULL SA
* Copyright (C) 2004 Silicon Graphics, Inc.
*
*/
#include <linux/sched.h>
#include <linux/cpumask.h>
#include <linux/nodemask.h>
#ifdef CONFIG_CPUSETS
extern int number_of_cpusets; /* How many cpusets are defined in system? */
extern int cpuset_init_early(void);
extern int cpuset_init(void);
extern void cpuset_init_smp(void);
extern void cpuset_fork(struct task_struct *p);
extern void cpuset_exit(struct task_struct *p);
extern cpumask_t cpuset_cpus_allowed(struct task_struct *p);
extern nodemask_t cpuset_mems_allowed(struct task_struct *p);
void cpuset_init_current_mems_allowed(void);
void cpuset_update_task_memory_state(void);
#define cpuset_nodes_subset_current_mems_allowed(nodes) \
nodes_subset((nodes), current->mems_allowed)
int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl);
extern int __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask);
static int inline cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
{
return number_of_cpusets <= 1 || __cpuset_zone_allowed(z, gfp_mask);
}
extern int cpuset_excl_nodes_overlap(const struct task_struct *p);
#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 struct file_operations proc_cpuset_operations;
extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer);
extern void cpuset_lock(void);
extern void cpuset_unlock(void);
#else /* !CONFIG_CPUSETS */
static inline int cpuset_init_early(void) { return 0; }
static inline int cpuset_init(void) { return 0; }
static inline void cpuset_init_smp(void) {}
static inline void cpuset_fork(struct task_struct *p) {}
static inline void cpuset_exit(struct task_struct *p) {}
static inline cpumask_t cpuset_cpus_allowed(struct task_struct *p)
{
return cpu_possible_map;
}
static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
{
return node_possible_map;
}
static inline void cpuset_init_current_mems_allowed(void) {}
static inline void cpuset_update_task_memory_state(void) {}
#define cpuset_nodes_subset_current_mems_allowed(nodes) (1)
static inline int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl)
{
return 1;
}
static inline int cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask)
{
return 1;
}
static inline int cpuset_excl_nodes_overlap(const struct task_struct *p)
{
return 1;
}
static inline void cpuset_memory_pressure_bump(void) {}
static inline char *cpuset_task_status_allowed(struct task_struct *task,
char *buffer)
{
return buffer;
}
static inline void cpuset_lock(void) {}
static inline void cpuset_unlock(void) {}
#endif /* !CONFIG_CPUSETS */
#endif /* _LINUX_CPUSET_H */