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