examples/performance-thread/common/lthread_cond.c

   1 /*
   2  * SPDX-License-Identifier: BSD-3-Clause
   3  * Copyright 2015 Intel Corporation.
   4  * Copyright 2012 Hasan Alayli <halayli@gmail.com>
   5  */
   6
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <stdint.h>
  11 #include <stddef.h>
  12 #include <limits.h>
  13 #include <inttypes.h>
  14 #include <unistd.h>
  15 #include <pthread.h>
  16 #include <fcntl.h>
  17 #include <sys/time.h>
  18 #include <sys/mman.h>
  19 #include <errno.h>
  20
  21 #include <rte_log.h>
  22 #include <rte_common.h>
  23
  24 #include "lthread_api.h"
  25 #include "lthread_diag_api.h"
  26 #include "lthread_diag.h"
  27 #include "lthread_int.h"
  28 #include "lthread_sched.h"
  29 #include "lthread_queue.h"
  30 #include "lthread_objcache.h"
  31 #include "lthread_timer.h"
  32 #include "lthread_mutex.h"
  33 #include "lthread_cond.h"
  34
  35 /*
  36  * Create a condition variable
  37  */
  38 int
  39 lthread_cond_init(char *name, struct lthread_cond **cond,
  40                   __rte_unused const struct lthread_condattr *attr)
  41 {
  42         struct lthread_cond *c;
  43
  44         if (cond == NULL)
  45                 return POSIX_ERRNO(EINVAL);
  46
  47         /* allocate a condition variable from cache */
  48         c = _lthread_objcache_alloc((THIS_SCHED)->cond_cache);
  49
  50         if (c == NULL)
  51                 return POSIX_ERRNO(EAGAIN);
  52
  53         c->blocked = _lthread_queue_create("blocked");
  54         if (c->blocked == NULL) {
  55                 _lthread_objcache_free((THIS_SCHED)->cond_cache, (void *)c);
  56                 return POSIX_ERRNO(EAGAIN);
  57         }
  58
  59         if (name == NULL)
  60                 strncpy(c->name, "no name", sizeof(c->name));
  61         else
  62                 strncpy(c->name, name, sizeof(c->name));
  63         c->name[sizeof(c->name)-1] = 0;
  64
  65         c->root_sched = THIS_SCHED;
  66
  67         (*cond) = c;
  68         DIAG_CREATE_EVENT((*cond), LT_DIAG_COND_CREATE);
  69         return 0;
  70 }
  71
  72 /*
  73  * Destroy a condition variable
  74  */
  75 int lthread_cond_destroy(struct lthread_cond *c)
  76 {
  77         if (c == NULL) {
  78                 DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EINVAL));
  79                 return POSIX_ERRNO(EINVAL);
  80         }
  81
  82         /* try to free it */
  83         if (_lthread_queue_destroy(c->blocked) < 0) {
  84                 /* queue in use */
  85                 DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, POSIX_ERRNO(EBUSY));
  86                 return POSIX_ERRNO(EBUSY);
  87         }
  88
  89         /* okay free it */
  90         _lthread_objcache_free(c->root_sched->cond_cache, c);
  91         DIAG_EVENT(c, LT_DIAG_COND_DESTROY, c, 0);
  92         return 0;
  93 }
  94
  95 /*
  96  * Wait on a condition variable
  97  */
  98 int lthread_cond_wait(struct lthread_cond *c, __rte_unused uint64_t reserved)
  99 {
 100         struct lthread *lt = THIS_LTHREAD;
 101
 102         if (c == NULL) {
 103                 DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, POSIX_ERRNO(EINVAL));
 104                 return POSIX_ERRNO(EINVAL);
 105         }
 106
 107
 108         DIAG_EVENT(c, LT_DIAG_COND_WAIT, c, 0);
 109
 110         /* queue the current thread in the blocked queue
 111          * this will be written when we return to the scheduler
 112          * to ensure that the current thread context is saved
 113          * before any signal could result in it being dequeued and
 114          * resumed
 115          */
 116         lt->pending_wr_queue = c->blocked;
 117         _suspend();
 118
 119         /* the condition happened */
 120         return 0;
 121 }
 122
 123 /*
 124  * Signal a condition variable
 125  * attempt to resume any blocked thread
 126  */
 127 int lthread_cond_signal(struct lthread_cond *c)
 128 {
 129         struct lthread *lt;
 130
 131         if (c == NULL) {
 132                 DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, POSIX_ERRNO(EINVAL));
 133                 return POSIX_ERRNO(EINVAL);
 134         }
 135
 136         lt = _lthread_queue_remove(c->blocked);
 137
 138         if (lt != NULL) {
 139                 /* okay wake up this thread */
 140                 DIAG_EVENT(c, LT_DIAG_COND_SIGNAL, c, lt);
 141                 _ready_queue_insert((struct lthread_sched *)lt->sched, lt);
 142         }
 143         return 0;
 144 }
 145
 146 /*
 147  * Broadcast a condition variable
 148  */
 149 int lthread_cond_broadcast(struct lthread_cond *c)
 150 {
 151         struct lthread *lt;
 152
 153         if (c == NULL) {
 154                 DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, POSIX_ERRNO(EINVAL));
 155                 return POSIX_ERRNO(EINVAL);
 156         }
 157
 158         DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
 159         do {
 160                 /* drain the queue waking everybody */
 161                 lt = _lthread_queue_remove(c->blocked);
 162
 163                 if (lt != NULL) {
 164                         DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, lt);
 165                         /* wake up */
 166                         _ready_queue_insert((struct lthread_sched *)lt->sched,
 167                                             lt);
 168                 }
 169         } while (!_lthread_queue_empty(c->blocked));
 170         _reschedule();
 171         DIAG_EVENT(c, LT_DIAG_COND_BROADCAST, c, 0);
 172         return 0;
 173 }
 174
 175 /*
 176  * return the diagnostic ref val stored in a condition var
 177  */
 178 uint64_t
 179 lthread_cond_diag_ref(struct lthread_cond *c)
 180 {
 181         if (c == NULL)
 182                 return 0;
 183         return c->diag_ref;
 184 }