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-rw-r--r--include/linux/iocontext.h95
1 files changed, 95 insertions, 0 deletions
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
new file mode 100644
index 000000000000..593b222d9dcc
--- /dev/null
+++ b/include/linux/iocontext.h
@@ -0,0 +1,95 @@
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 */
9struct 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
32struct cfq_queue;
33struct 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
54 void (*dtor)(struct io_context *); /* destructor */
55 void (*exit)(struct io_context *); /* called on task exit */
56};
57
58/*
59 * I/O subsystem state of the associated processes. It is refcounted
60 * and kmalloc'ed. These could be shared between processes.
61 */
62struct io_context {
63 atomic_t refcount;
64 atomic_t nr_tasks;
65
66 /* all the fields below are protected by this lock */
67 spinlock_t lock;
68
69 unsigned short ioprio;
70 unsigned short ioprio_changed;
71
72 /*
73 * For request batching
74 */
75 unsigned long last_waited; /* Time last woken after wait for request */
76 int nr_batch_requests; /* Number of requests left in the batch */
77
78 struct as_io_context *aic;
79 struct radix_tree_root radix_root;
80 void *ioc_data;
81};
82
83static inline struct io_context *ioc_task_link(struct io_context *ioc)
84{
85 /*
86 * if ref count is zero, don't allow sharing (ioc is going away, it's
87 * a race).
88 */
89 if (ioc && atomic_inc_not_zero(&ioc->refcount))
90 return ioc;
91
92 return NULL;
93}
94
95#endif