linux-kernel-test/include/linux/cpuset.h
Miao Xie c0ff7453bb cpuset,mm: fix no node to alloc memory when changing cpuset's mems
Before applying this patch, cpuset updates task->mems_allowed and
mempolicy by setting all new bits in the nodemask first, and clearing all
old unallowed bits later.  But in the way, the allocator may find that
there is no node to alloc memory.

The reason is that cpuset rebinds the task's mempolicy, it cleans the
nodes which the allocater can alloc pages on, for example:

(mpol: mempolicy)
	task1			task1's mpol	task2
	alloc page		1
	  alloc on node0? NO	1
				1		change mems from 1 to 0
				1		rebind task1's mpol
				0-1		  set new bits
				0	  	  clear disallowed bits
	  alloc on node1? NO	0
	  ...
	can't alloc page
	  goto oom

This patch fixes this problem by expanding the nodes range first(set newly
allowed bits) and shrink it lazily(clear newly disallowed bits).  So we
use a variable to tell the write-side task that read-side task is reading
nodemask, and the write-side task clears newly disallowed nodes after
read-side task ends the current memory allocation.

[akpm@linux-foundation.org: fix spello]
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Paul Menage <menage@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-25 08:06:57 -07:00

236 lines
5.5 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);
/*
* reading current mems_allowed and mempolicy in the fastpath must protected
* by get_mems_allowed()
*/
static inline void get_mems_allowed(void)
{
current->mems_allowed_change_disable++;
/*
* ensure that reading mems_allowed and mempolicy happens after the
* update of ->mems_allowed_change_disable.
*
* the write-side task finds ->mems_allowed_change_disable is not 0,
* and knows the read-side task is reading mems_allowed or mempolicy,
* so it will clear old bits lazily.
*/
smp_mb();
}
static inline void put_mems_allowed(void)
{
/*
* ensure that reading mems_allowed and mempolicy before reducing
* mems_allowed_change_disable.
*
* the write-side task will know that the read-side task is still
* reading mems_allowed or mempolicy, don't clears old bits in the
* nodemask.
*/
smp_mb();
--ACCESS_ONCE(current->mems_allowed_change_disable);
}
static inline void set_mems_allowed(nodemask_t nodemask)
{
task_lock(current);
current->mems_allowed = nodemask;
task_unlock(current);
}
#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)
{
}
static inline void get_mems_allowed(void)
{
}
static inline void put_mems_allowed(void)
{
}
#endif /* !CONFIG_CPUSETS */
#endif /* _LINUX_CPUSET_H */