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Diffstat (limited to '')
| -rw-r--r-- | include/linux/cpuset.h | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h new file mode 100644 index 000000000..934633a05 --- /dev/null +++ b/include/linux/cpuset.h @@ -0,0 +1,280 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#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/sched/topology.h> +#include <linux/sched/task.h> +#include <linux/cpumask.h> +#include <linux/nodemask.h> +#include <linux/mm.h> +#include <linux/jump_label.h> + +#ifdef CONFIG_CPUSETS + +/* + * Static branch rewrites can happen in an arbitrary order for a given + * key. In code paths where we need to loop with read_mems_allowed_begin() and + * read_mems_allowed_retry() to get a consistent view of mems_allowed, we need + * to ensure that begin() always gets rewritten before retry() in the + * disabled -> enabled transition. If not, then if local irqs are disabled + * around the loop, we can deadlock since retry() would always be + * comparing the latest value of the mems_allowed seqcount against 0 as + * begin() still would see cpusets_enabled() as false. The enabled -> disabled + * transition should happen in reverse order for the same reasons (want to stop + * looking at real value of mems_allowed.sequence in retry() first). + */ +extern struct static_key_false cpusets_pre_enable_key; +extern struct static_key_false cpusets_enabled_key; +static inline bool cpusets_enabled(void) +{ + return static_branch_unlikely(&cpusets_enabled_key); +} + +static inline void cpuset_inc(void) +{ + static_branch_inc(&cpusets_pre_enable_key); + static_branch_inc(&cpusets_enabled_key); +} + +static inline void cpuset_dec(void) +{ + static_branch_dec(&cpusets_enabled_key); + static_branch_dec(&cpusets_pre_enable_key); +} + +extern int cpuset_init(void); +extern void cpuset_init_smp(void); +extern void cpuset_force_rebuild(void); +extern void cpuset_update_active_cpus(void); +extern void cpuset_wait_for_hotplug(void); +extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask); +extern void 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 bool __cpuset_node_allowed(int node, gfp_t gfp_mask); + +static inline bool cpuset_node_allowed(int node, gfp_t gfp_mask) +{ + if (cpusets_enabled()) + return __cpuset_node_allowed(node, gfp_mask); + return true; +} + +static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) +{ + return __cpuset_node_allowed(zone_to_nid(z), gfp_mask); +} + +static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) +{ + if (cpusets_enabled()) + return __cpuset_zone_allowed(z, gfp_mask); + return true; +} + +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 void cpuset_task_status_allowed(struct seq_file *m, + struct task_struct *task); +extern int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns, + struct pid *pid, struct task_struct *tsk); + +extern int cpuset_mem_spread_node(void); +extern int cpuset_slab_spread_node(void); + +static inline int cpuset_do_page_mem_spread(void) +{ + return task_spread_page(current); +} + +static inline int cpuset_do_slab_mem_spread(void) +{ + return task_spread_slab(current); +} + +extern bool current_cpuset_is_being_rebound(void); + +extern void rebuild_sched_domains(void); + +extern void cpuset_print_current_mems_allowed(void); + +/* + * read_mems_allowed_begin is required when making decisions involving + * mems_allowed such as during page allocation. mems_allowed can be updated in + * parallel and depending on the new value an operation can fail potentially + * causing process failure. A retry loop with read_mems_allowed_begin and + * read_mems_allowed_retry prevents these artificial failures. + */ +static inline unsigned int read_mems_allowed_begin(void) +{ + if (!static_branch_unlikely(&cpusets_pre_enable_key)) + return 0; + + return read_seqcount_begin(¤t->mems_allowed_seq); +} + +/* + * If this returns true, the operation that took place after + * read_mems_allowed_begin may have failed artificially due to a concurrent + * update of mems_allowed. It is up to the caller to retry the operation if + * appropriate. + */ +static inline bool read_mems_allowed_retry(unsigned int seq) +{ + if (!static_branch_unlikely(&cpusets_enabled_key)) + return false; + + return read_seqcount_retry(¤t->mems_allowed_seq, seq); +} + +static inline void set_mems_allowed(nodemask_t nodemask) +{ + unsigned long flags; + + task_lock(current); + local_irq_save(flags); + write_seqcount_begin(¤t->mems_allowed_seq); + current->mems_allowed = nodemask; + write_seqcount_end(¤t->mems_allowed_seq); + local_irq_restore(flags); + task_unlock(current); +} + +#else /* !CONFIG_CPUSETS */ + +static inline bool cpusets_enabled(void) { return false; } + +static inline int cpuset_init(void) { return 0; } +static inline void cpuset_init_smp(void) {} + +static inline void cpuset_force_rebuild(void) { } + +static inline void cpuset_update_active_cpus(void) +{ + partition_sched_domains(1, NULL, NULL); +} + +static inline void cpuset_wait_for_hotplug(void) { } + +static inline void cpuset_cpus_allowed(struct task_struct *p, + struct cpumask *mask) +{ + cpumask_copy(mask, cpu_possible_mask); +} + +static inline void cpuset_cpus_allowed_fallback(struct task_struct *p) +{ +} + +static inline nodemask_t cpuset_mems_allowed(struct task_struct *p) +{ + return node_possible_map; +} + +#define cpuset_current_mems_allowed (node_states[N_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 bool cpuset_node_allowed(int node, gfp_t gfp_mask) +{ + return true; +} + +static inline bool __cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) +{ + return true; +} + +static inline bool cpuset_zone_allowed(struct zone *z, gfp_t gfp_mask) +{ + return true; +} + +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_slab_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 bool current_cpuset_is_being_rebound(void) +{ + return false; +} + +static inline void rebuild_sched_domains(void) +{ + partition_sched_domains(1, NULL, NULL); +} + +static inline void cpuset_print_current_mems_allowed(void) +{ +} + +static inline void set_mems_allowed(nodemask_t nodemask) +{ +} + +static inline unsigned int read_mems_allowed_begin(void) +{ + return 0; +} + +static inline bool read_mems_allowed_retry(unsigned int seq) +{ + return false; +} + +#endif /* !CONFIG_CPUSETS */ + +#endif /* _LINUX_CPUSET_H */ |