1#include "fio.h"
2#include "mutex.h"
3#include "smalloc.h"
4#include "flist.h"
5
6struct fio_flow {
7	unsigned int refs;
8	struct flist_head list;
9	unsigned int id;
10	long long int flow_counter;
11};
12
13static struct flist_head *flow_list;
14static struct fio_mutex *flow_lock;
15
16int flow_threshold_exceeded(struct thread_data *td)
17{
18	struct fio_flow *flow = td->flow;
19	int sign;
20
21	if (!flow)
22		return 0;
23
24	sign = td->o.flow > 0 ? 1 : -1;
25	if (sign * flow->flow_counter > td->o.flow_watermark) {
26		if (td->o.flow_sleep) {
27			io_u_quiesce(td);
28			usleep(td->o.flow_sleep);
29		}
30
31		return 1;
32	}
33
34	/* No synchronization needed because it doesn't
35	 * matter if the flow count is slightly inaccurate */
36	flow->flow_counter += td->o.flow;
37	return 0;
38}
39
40static struct fio_flow *flow_get(unsigned int id)
41{
42	struct fio_flow *flow = NULL;
43	struct flist_head *n;
44
45	if (!flow_lock)
46		return NULL;
47
48	fio_mutex_down(flow_lock);
49
50	flist_for_each(n, flow_list) {
51		flow = flist_entry(n, struct fio_flow, list);
52		if (flow->id == id)
53			break;
54
55		flow = NULL;
56	}
57
58	if (!flow) {
59		flow = smalloc(sizeof(*flow));
60		if (!flow) {
61			log_err("fio: smalloc pool exhausted\n");
62			return NULL;
63		}
64		flow->refs = 0;
65		INIT_FLIST_HEAD(&flow->list);
66		flow->id = id;
67		flow->flow_counter = 0;
68
69		flist_add_tail(&flow->list, flow_list);
70	}
71
72	flow->refs++;
73	fio_mutex_up(flow_lock);
74	return flow;
75}
76
77static void flow_put(struct fio_flow *flow)
78{
79	if (!flow_lock)
80		return;
81
82	fio_mutex_down(flow_lock);
83
84	if (!--flow->refs) {
85		flist_del(&flow->list);
86		sfree(flow);
87	}
88
89	fio_mutex_up(flow_lock);
90}
91
92void flow_init_job(struct thread_data *td)
93{
94	if (td->o.flow)
95		td->flow = flow_get(td->o.flow_id);
96}
97
98void flow_exit_job(struct thread_data *td)
99{
100	if (td->flow) {
101		flow_put(td->flow);
102		td->flow = NULL;
103	}
104}
105
106void flow_init(void)
107{
108	flow_list = smalloc(sizeof(*flow_list));
109	if (!flow_list) {
110		log_err("fio: smalloc pool exhausted\n");
111		return;
112	}
113
114	flow_lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
115	if (!flow_lock) {
116		log_err("fio: failed to allocate flow lock\n");
117		sfree(flow_list);
118		return;
119	}
120
121	INIT_FLIST_HEAD(flow_list);
122}
123
124void flow_exit(void)
125{
126	if (flow_lock)
127		fio_mutex_remove(flow_lock);
128	if (flow_list)
129		sfree(flow_list);
130}
131