1 #ifndef IOCONTEXT_H 2 #define IOCONTEXT_H 3 4 #include <linux/radix-tree.h> 5 6 /* 7 * This is the per-process anticipatory I/O scheduler state. 8 */ 9 struct as_io_context { 10 spinlock_t lock; 11 12 void (*dtor)(struct as_io_context *aic); /* destructor */ 13 void (*exit)(struct as_io_context *aic); /* called on task exit */ 14 15 unsigned long state; 16 atomic_t nr_queued; /* queued reads & sync writes */ 17 atomic_t nr_dispatched; /* number of requests gone to the drivers */ 18 19 /* IO History tracking */ 20 /* Thinktime */ 21 unsigned long last_end_request; 22 unsigned long ttime_total; 23 unsigned long ttime_samples; 24 unsigned long ttime_mean; 25 /* Layout pattern */ 26 unsigned int seek_samples; 27 sector_t last_request_pos; 28 u64 seek_total; 29 sector_t seek_mean; 30 }; 31 32 struct cfq_queue; 33 struct cfq_io_context { 34 void *key; 35 unsigned long dead_key; 36 37 struct cfq_queue *cfqq[2]; 38 39 struct io_context *ioc; 40 41 unsigned long last_end_request; 42 sector_t last_request_pos; 43 44 unsigned long ttime_total; 45 unsigned long ttime_samples; 46 unsigned long ttime_mean; 47 48 unsigned int seek_samples; 49 u64 seek_total; 50 sector_t seek_mean; 51 52 struct list_head queue_list; 53 struct hlist_node cic_list; 54 55 void (*dtor)(struct io_context *); /* destructor */ 56 void (*exit)(struct io_context *); /* called on task exit */ 57 }; 58 59 /* 60 * I/O subsystem state of the associated processes. It is refcounted 61 * and kmalloc'ed. These could be shared between processes. 62 */ 63 struct io_context { 64 atomic_t refcount; 65 atomic_t nr_tasks; 66 67 /* all the fields below are protected by this lock */ 68 spinlock_t lock; 69 70 unsigned short ioprio; 71 unsigned short ioprio_changed; 72 73 /* 74 * For request batching 75 */ 76 unsigned long last_waited; /* Time last woken after wait for request */ 77 int nr_batch_requests; /* Number of requests left in the batch */ 78 79 struct as_io_context *aic; 80 struct radix_tree_root radix_root; 81 struct hlist_head cic_list; 82 void *ioc_data; 83 }; 84 85 static inline struct io_context *ioc_task_link(struct io_context *ioc) 86 { 87 /* 88 * if ref count is zero, don't allow sharing (ioc is going away, it's 89 * a race). 90 */ 91 if (ioc && atomic_inc_not_zero(&ioc->refcount)) 92 return ioc; 93 94 return NULL; 95 } 96 97 #endif 98