9bf2229f88
This patch makes use of the previously underutilized cpuset flag 'mem_exclusive' to provide what amounts to another layer of memory placement resolution. With this patch, there are now the following four layers of memory placement available: 1) The whole system (interrupt and GFP_ATOMIC allocations can use this), 2) The nearest enclosing mem_exclusive cpuset (GFP_KERNEL allocations can use), 3) The current tasks cpuset (GFP_USER allocations constrained to here), and 4) Specific node placement, using mbind and set_mempolicy. These nest - each layer is a subset (same or within) of the previous. Layer (2) above is new, with this patch. The call used to check whether a zone (its node, actually) is in a cpuset (in its mems_allowed, actually) is extended to take a gfp_mask argument, and its logic is extended, in the case that __GFP_HARDWALL is not set in the flag bits, to look up the cpuset hierarchy for the nearest enclosing mem_exclusive cpuset, to determine if placement is allowed. The definition of GFP_USER, which used to be identical to GFP_KERNEL, is changed to also set the __GFP_HARDWALL bit, in the previous cpuset_gfp_hardwall_flag patch. GFP_ATOMIC and GFP_KERNEL allocations will stay within the current tasks cpuset, so long as any node therein is not too tight on memory, but will escape to the larger layer, if need be. The intended use is to allow something like a batch manager to handle several jobs, each job in its own cpuset, but using common kernel memory for caches and such. Swapper and oom_kill activity is also constrained to Layer (2). A task in or below one mem_exclusive cpuset should not cause swapping on nodes in another non-overlapping mem_exclusive cpuset, nor provoke oom_killing of a task in another such cpuset. Heavy use of kernel memory for i/o caching and such by one job should not impact the memory available to jobs in other non-overlapping mem_exclusive cpusets. This patch enables providing hardwall, inescapable cpusets for memory allocations of each job, while sharing kernel memory allocations between several jobs, in an enclosing mem_exclusive cpuset. Like Dinakar's patch earlier to enable administering sched domains using the cpu_exclusive flag, this patch also provides a useful meaning to a cpuset flag that had previously done nothing much useful other than restrict what cpuset configurations were allowed. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
66 lines
1.8 KiB
C
66 lines
1.8 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 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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#ifdef CONFIG_CPUSETS
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extern int cpuset_init(void);
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extern void cpuset_init_smp(void);
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extern void cpuset_fork(struct task_struct *p);
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extern void cpuset_exit(struct task_struct *p);
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extern cpumask_t cpuset_cpus_allowed(const struct task_struct *p);
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void cpuset_init_current_mems_allowed(void);
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void cpuset_update_current_mems_allowed(void);
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void cpuset_restrict_to_mems_allowed(unsigned long *nodes);
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int cpuset_zonelist_valid_mems_allowed(struct zonelist *zl);
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extern int cpuset_zone_allowed(struct zone *z, unsigned int __nocast gfp_mask);
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extern 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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#else /* !CONFIG_CPUSETS */
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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 void cpuset_fork(struct task_struct *p) {}
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static inline void cpuset_exit(struct task_struct *p) {}
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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 void cpuset_init_current_mems_allowed(void) {}
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static inline void cpuset_update_current_mems_allowed(void) {}
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static inline void cpuset_restrict_to_mems_allowed(unsigned long *nodes) {}
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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(struct zone *z,
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unsigned int __nocast gfp_mask)
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{
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return 1;
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}
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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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#endif /* !CONFIG_CPUSETS */
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#endif /* _LINUX_CPUSET_H */
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