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