4 #include <linux/radix-tree.h>
5 #include <linux/rcupdate.h>
8 * This is the per-process anticipatory I/O scheduler state.
10 struct as_io_context {
13 void (*dtor)(struct as_io_context *aic); /* destructor */
14 void (*exit)(struct as_io_context *aic); /* called on task exit */
17 atomic_t nr_queued; /* queued reads & sync writes */
18 atomic_t nr_dispatched; /* number of requests gone to the drivers */
20 /* IO History tracking */
22 unsigned long last_end_request;
23 unsigned long ttime_total;
24 unsigned long ttime_samples;
25 unsigned long ttime_mean;
27 unsigned int seek_samples;
28 sector_t last_request_pos;
34 struct cfq_io_context {
36 unsigned long dead_key;
38 struct cfq_queue *cfqq[2];
40 struct io_context *ioc;
42 unsigned long last_end_request;
44 unsigned long ttime_total;
45 unsigned long ttime_samples;
46 unsigned long ttime_mean;
48 struct list_head queue_list;
49 struct hlist_node cic_list;
51 void (*dtor)(struct io_context *); /* destructor */
52 void (*exit)(struct io_context *); /* called on task exit */
54 struct rcu_head rcu_head;
58 * I/O subsystem state of the associated processes. It is refcounted
59 * and kmalloc'ed. These could be shared between processes.
62 atomic_long_t refcount;
65 /* all the fields below are protected by this lock */
68 unsigned short ioprio;
69 unsigned short ioprio_changed;
71 #ifdef CONFIG_BLK_CGROUP
72 unsigned short cgroup_changed;
76 * For request batching
78 unsigned long last_waited; /* Time last woken after wait for request */
79 int nr_batch_requests; /* Number of requests left in the batch */
81 struct as_io_context *aic;
82 struct radix_tree_root radix_root;
83 struct hlist_head cic_list;
87 static inline struct io_context *ioc_task_link(struct io_context *ioc)
90 * if ref count is zero, don't allow sharing (ioc is going away, it's
93 if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
94 atomic_inc(&ioc->nr_tasks);
103 int put_io_context(struct io_context *ioc);
104 void exit_io_context(struct task_struct *task);
105 struct io_context *get_io_context(gfp_t gfp_flags, int node);
106 struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
107 void copy_io_context(struct io_context **pdst, struct io_context **psrc);
109 static inline void exit_io_context(struct task_struct *task)
114 static inline int put_io_context(struct io_context *ioc)