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