lib/eal/linux/eal_alarm.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4 #include <stdio.h>
   5 #include <stdint.h>
   6 #include <errno.h>
   7 #include <sys/queue.h>
   8 #include <sys/time.h>
   9 #include <sys/timerfd.h>
  10
  11 #include <rte_interrupts.h>
  12 #include <rte_alarm.h>
  13 #include <rte_common.h>
  14 #include <rte_errno.h>
  15 #include <rte_spinlock.h>
  16 #include <rte_eal_trace.h>
  17
  18 #include <eal_private.h>
  19
  20 #ifndef TFD_NONBLOCK
  21 #include <fcntl.h>
  22 #define TFD_NONBLOCK    O_NONBLOCK
  23 #endif
  24
  25 #define NS_PER_US 1000
  26 #define US_PER_MS 1000
  27 #define MS_PER_S 1000
  28 #ifndef US_PER_S
  29 #define US_PER_S (US_PER_MS * MS_PER_S)
  30 #endif
  31
  32 #ifdef CLOCK_MONOTONIC_RAW /* Defined in glibc bits/time.h */
  33 #define CLOCK_TYPE_ID CLOCK_MONOTONIC_RAW
  34 #else
  35 #define CLOCK_TYPE_ID CLOCK_MONOTONIC
  36 #endif
  37
  38 struct alarm_entry {
  39         LIST_ENTRY(alarm_entry) next;
  40         struct timeval time;
  41         rte_eal_alarm_callback cb_fn;
  42         void *cb_arg;
  43         volatile uint8_t executing;
  44         volatile pthread_t executing_id;
  45 };
  46
  47 static LIST_HEAD(alarm_list, alarm_entry) alarm_list = LIST_HEAD_INITIALIZER();
  48 static rte_spinlock_t alarm_list_lk = RTE_SPINLOCK_INITIALIZER;
  49
  50 static struct rte_intr_handle *intr_handle;
  51 static int handler_registered = 0;
  52 static void eal_alarm_callback(void *arg);
  53
  54 void
  55 rte_eal_alarm_cleanup(void)
  56 {
  57         rte_intr_instance_free(intr_handle);
  58 }
  59
  60 int
  61 rte_eal_alarm_init(void)
  62 {
  63
  64         intr_handle = rte_intr_instance_alloc(RTE_INTR_INSTANCE_F_PRIVATE);
  65         if (intr_handle == NULL) {
  66                 RTE_LOG(ERR, EAL, "Fail to allocate intr_handle\n");
  67                 goto error;
  68         }
  69
  70         if (rte_intr_type_set(intr_handle, RTE_INTR_HANDLE_ALARM))
  71                 goto error;
  72
  73         /* create a timerfd file descriptor */
  74         if (rte_intr_fd_set(intr_handle,
  75                         timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK)))
  76                 goto error;
  77
  78         if (rte_intr_fd_get(intr_handle) == -1)
  79                 goto error;
  80         return 0;
  81
  82 error:
  83         rte_intr_instance_free(intr_handle);
  84         rte_errno = errno;
  85         return -1;
  86 }
  87
  88 static void
  89 eal_alarm_callback(void *arg __rte_unused)
  90 {
  91         struct timespec now;
  92         struct alarm_entry *ap;
  93
  94         rte_spinlock_lock(&alarm_list_lk);
  95         while ((ap = LIST_FIRST(&alarm_list)) !=NULL &&
  96                         clock_gettime(CLOCK_TYPE_ID, &now) == 0 &&
  97                         (ap->time.tv_sec < now.tv_sec || (ap->time.tv_sec == now.tv_sec &&
  98                                                 (ap->time.tv_usec * NS_PER_US) <= now.tv_nsec))) {
  99                 ap->executing = 1;
 100                 ap->executing_id = pthread_self();
 101                 rte_spinlock_unlock(&alarm_list_lk);
 102
 103                 ap->cb_fn(ap->cb_arg);
 104
 105                 rte_spinlock_lock(&alarm_list_lk);
 106
 107                 LIST_REMOVE(ap, next);
 108                 free(ap);
 109         }
 110
 111         if (!LIST_EMPTY(&alarm_list)) {
 112                 struct itimerspec atime = { .it_interval = { 0, 0 } };
 113
 114                 ap = LIST_FIRST(&alarm_list);
 115                 atime.it_value.tv_sec = ap->time.tv_sec;
 116                 atime.it_value.tv_nsec = ap->time.tv_usec * NS_PER_US;
 117                 /* perform borrow for subtraction if necessary */
 118                 if (now.tv_nsec > (ap->time.tv_usec * NS_PER_US))
 119                         atime.it_value.tv_sec--, atime.it_value.tv_nsec += US_PER_S * NS_PER_US;
 120
 121                 atime.it_value.tv_sec -= now.tv_sec;
 122                 atime.it_value.tv_nsec -= now.tv_nsec;
 123                 timerfd_settime(rte_intr_fd_get(intr_handle), 0, &atime, NULL);
 124         }
 125         rte_spinlock_unlock(&alarm_list_lk);
 126 }
 127
 128 int
 129 rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback cb_fn, void *cb_arg)
 130 {
 131         struct timespec now;
 132         int ret = 0;
 133         struct alarm_entry *ap, *new_alarm;
 134
 135         /* Check parameters, including that us won't cause a uint64_t overflow */
 136         if (us < 1 || us > (UINT64_MAX - US_PER_S) || cb_fn == NULL)
 137                 return -EINVAL;
 138
 139         new_alarm = calloc(1, sizeof(*new_alarm));
 140         if (new_alarm == NULL)
 141                 return -ENOMEM;
 142
 143         /* use current time to calculate absolute time of alarm */
 144         clock_gettime(CLOCK_TYPE_ID, &now);
 145
 146         new_alarm->cb_fn = cb_fn;
 147         new_alarm->cb_arg = cb_arg;
 148         new_alarm->time.tv_usec = ((now.tv_nsec / NS_PER_US) + us) % US_PER_S;
 149         new_alarm->time.tv_sec = now.tv_sec + (((now.tv_nsec / NS_PER_US) + us) / US_PER_S);
 150
 151         rte_spinlock_lock(&alarm_list_lk);
 152         if (!handler_registered) {
 153                 /* registration can fail, callback can be registered later */
 154                 if (rte_intr_callback_register(intr_handle,
 155                                 eal_alarm_callback, NULL) == 0)
 156                         handler_registered = 1;
 157         }
 158
 159         if (LIST_EMPTY(&alarm_list))
 160                 LIST_INSERT_HEAD(&alarm_list, new_alarm, next);
 161         else {
 162                 LIST_FOREACH(ap, &alarm_list, next) {
 163                         if (ap->time.tv_sec > new_alarm->time.tv_sec ||
 164                                         (ap->time.tv_sec == new_alarm->time.tv_sec &&
 165                                                         ap->time.tv_usec > new_alarm->time.tv_usec)){
 166                                 LIST_INSERT_BEFORE(ap, new_alarm, next);
 167                                 break;
 168                         }
 169                         if (LIST_NEXT(ap, next) == NULL) {
 170                                 LIST_INSERT_AFTER(ap, new_alarm, next);
 171                                 break;
 172                         }
 173                 }
 174         }
 175
 176         if (LIST_FIRST(&alarm_list) == new_alarm) {
 177                 struct itimerspec alarm_time = {
 178                         .it_interval = {0, 0},
 179                         .it_value = {
 180                                 .tv_sec = us / US_PER_S,
 181                                 .tv_nsec = (us % US_PER_S) * NS_PER_US,
 182                         },
 183                 };
 184                 ret |= timerfd_settime(rte_intr_fd_get(intr_handle), 0, &alarm_time, NULL);
 185         }
 186         rte_spinlock_unlock(&alarm_list_lk);
 187
 188         rte_eal_trace_alarm_set(us, cb_fn, cb_arg, ret);
 189         return ret;
 190 }
 191
 192 int
 193 rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn, void *cb_arg)
 194 {
 195         struct alarm_entry *ap, *ap_prev;
 196         int count = 0;
 197         int err = 0;
 198         int executing;
 199
 200         if (!cb_fn) {
 201                 rte_errno = EINVAL;
 202                 return -1;
 203         }
 204
 205         do {
 206                 executing = 0;
 207                 rte_spinlock_lock(&alarm_list_lk);
 208                 /* remove any matches at the start of the list */
 209                 while ((ap = LIST_FIRST(&alarm_list)) != NULL &&
 210                                 cb_fn == ap->cb_fn &&
 211                                 (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) {
 212
 213                         if (ap->executing == 0) {
 214                                 LIST_REMOVE(ap, next);
 215                                 free(ap);
 216                                 count++;
 217                         } else {
 218                                 /* If calling from other context, mark that alarm is executing
 219                                  * so loop can spin till it finish. Otherwise we are trying to
 220                                  * cancel our self - mark it by EINPROGRESS */
 221                                 if (pthread_equal(ap->executing_id, pthread_self()) == 0)
 222                                         executing++;
 223                                 else
 224                                         err = EINPROGRESS;
 225
 226                                 break;
 227                         }
 228                 }
 229                 ap_prev = ap;
 230
 231                 /* now go through list, removing entries not at start */
 232                 LIST_FOREACH(ap, &alarm_list, next) {
 233                         /* this won't be true first time through */
 234                         if (cb_fn == ap->cb_fn &&
 235                                         (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) {
 236
 237                                 if (ap->executing == 0) {
 238                                         LIST_REMOVE(ap, next);
 239                                         free(ap);
 240                                         count++;
 241                                         ap = ap_prev;
 242                                 } else if (pthread_equal(ap->executing_id, pthread_self()) == 0)
 243                                         executing++;
 244                                 else
 245                                         err = EINPROGRESS;
 246                         }
 247                         ap_prev = ap;
 248                 }
 249                 rte_spinlock_unlock(&alarm_list_lk);
 250         } while (executing != 0);
 251
 252         if (count == 0 && err == 0)
 253                 rte_errno = ENOENT;
 254         else if (err)
 255                 rte_errno = err;
 256
 257         rte_eal_trace_alarm_cancel(cb_fn, cb_arg, count);
 258         return count;
 259 }