tools/testing/radix-tree/rcupdate.c

   1 #include <linux/rcupdate.h>
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <assert.h>
   5
   6 static pthread_mutex_t rculock = PTHREAD_MUTEX_INITIALIZER;
   7 static struct rcu_head *rcuhead_global = NULL;
   8 static __thread int nr_rcuhead = 0;
   9 static __thread struct rcu_head *rcuhead = NULL;
  10 static __thread struct rcu_head *rcutail = NULL;
  11
  12 static pthread_cond_t rcu_worker_cond = PTHREAD_COND_INITIALIZER;
  13
  14 /* switch to urcu implementation when it is merged. */
  15 void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *head))
  16 {
  17         head->func = func;
  18         head->next = rcuhead;
  19         rcuhead = head;
  20         if (!rcutail)
  21                 rcutail = head;
  22         nr_rcuhead++;
  23         if (nr_rcuhead >= 1000) {
  24                 int signal = 0;
  25
  26                 pthread_mutex_lock(&rculock);
  27                 if (!rcuhead_global)
  28                         signal = 1;
  29                 rcutail->next = rcuhead_global;
  30                 rcuhead_global = head;
  31                 pthread_mutex_unlock(&rculock);
  32
  33                 nr_rcuhead = 0;
  34                 rcuhead = NULL;
  35                 rcutail = NULL;
  36
  37                 if (signal) {
  38                         pthread_cond_signal(&rcu_worker_cond);
  39                 }
  40         }
  41 }
  42
  43 static void *rcu_worker(void *arg)
  44 {
  45         struct rcu_head *r;
  46
  47         rcupdate_thread_init();
  48
  49         while (1) {
  50                 pthread_mutex_lock(&rculock);
  51                 while (!rcuhead_global) {
  52                         pthread_cond_wait(&rcu_worker_cond, &rculock);
  53                 }
  54                 r = rcuhead_global;
  55                 rcuhead_global = NULL;
  56
  57                 pthread_mutex_unlock(&rculock);
  58
  59                 synchronize_rcu();
  60
  61                 while (r) {
  62                         struct rcu_head *tmp = r->next;
  63                         r->func(r);
  64                         r = tmp;
  65                 }
  66         }
  67
  68         rcupdate_thread_exit();
  69
  70         return NULL;
  71 }
  72
  73 static pthread_t worker_thread;
  74 void rcupdate_init(void)
  75 {
  76         pthread_create(&worker_thread, NULL, rcu_worker, NULL);
  77 }
  78
  79 void rcupdate_thread_init(void)
  80 {
  81         rcu_register_thread();
  82 }
  83 void rcupdate_thread_exit(void)
  84 {
  85         rcu_unregister_thread();
  86 }