flow.c

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