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