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 <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;
  58 static int handler_registered = 0;
  59 static void eal_alarm_callback(void *arg);
  60
  61 void
  62 rte_eal_alarm_cleanup(void)
  63 {
  64         rte_intr_instance_free(intr_handle);
  65 }
  66
  67 int
  68 rte_eal_alarm_init(void)
  69 {
  70
  71         intr_handle = rte_intr_instance_alloc(RTE_INTR_INSTANCE_F_PRIVATE);
  72         if (intr_handle == NULL) {
  73                 RTE_LOG(ERR, EAL, "Fail to allocate intr_handle\n");
  74                 goto error;
  75         }
  76
  77         if (rte_intr_type_set(intr_handle, RTE_INTR_HANDLE_ALARM))
  78                 goto error;
  79
  80         /* create a timerfd file descriptor */
  81         if (rte_intr_fd_set(intr_handle,
  82                         timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK)))
  83                 goto error;
  84
  85         if (rte_intr_fd_get(intr_handle) == -1)
  86                 goto error;
  87         return 0;
  88
  89 error:
  90         rte_intr_instance_free(intr_handle);
  91         rte_errno = errno;
  92         return -1;
  93 }
  94
  95 static void
  96 eal_alarm_callback(void *arg __rte_unused)
  97 {
  98         struct timespec now;
  99         struct alarm_entry *ap;
 100
 101         rte_spinlock_lock(&alarm_list_lk);
 102         while ((ap = LIST_FIRST(&alarm_list)) !=NULL &&
 103                         clock_gettime(CLOCK_TYPE_ID, &now) == 0 &&
 104                         (ap->time.tv_sec < now.tv_sec || (ap->time.tv_sec == now.tv_sec &&
 105                                                 (ap->time.tv_usec * NS_PER_US) <= now.tv_nsec))) {
 106                 ap->executing = 1;
 107                 ap->executing_id = pthread_self();
 108                 rte_spinlock_unlock(&alarm_list_lk);
 109
 110                 ap->cb_fn(ap->cb_arg);
 111
 112                 rte_spinlock_lock(&alarm_list_lk);
 113
 114                 LIST_REMOVE(ap, next);
 115                 free(ap);
 116         }
 117
 118         if (!LIST_EMPTY(&alarm_list)) {
 119                 struct itimerspec atime = { .it_interval = { 0, 0 } };
 120
 121                 ap = LIST_FIRST(&alarm_list);
 122                 atime.it_value.tv_sec = ap->time.tv_sec;
 123                 atime.it_value.tv_nsec = ap->time.tv_usec * NS_PER_US;
 124                 /* perform borrow for subtraction if necessary */
 125                 if (now.tv_nsec > (ap->time.tv_usec * NS_PER_US))
 126                         atime.it_value.tv_sec--, atime.it_value.tv_nsec += US_PER_S * NS_PER_US;
 127
 128                 atime.it_value.tv_sec -= now.tv_sec;
 129                 atime.it_value.tv_nsec -= now.tv_nsec;
 130                 timerfd_settime(rte_intr_fd_get(intr_handle), 0, &atime, NULL);
 131         }
 132         rte_spinlock_unlock(&alarm_list_lk);
 133 }
 134
 135 int
 136 rte_eal_alarm_set(uint64_t us, rte_eal_alarm_callback cb_fn, void *cb_arg)
 137 {
 138         struct timespec now;
 139         int ret = 0;
 140         struct alarm_entry *ap, *new_alarm;
 141
 142         /* Check parameters, including that us won't cause a uint64_t overflow */
 143         if (us < 1 || us > (UINT64_MAX - US_PER_S) || cb_fn == NULL)
 144                 return -EINVAL;
 145
 146         new_alarm = calloc(1, sizeof(*new_alarm));
 147         if (new_alarm == NULL)
 148                 return -ENOMEM;
 149
 150         /* use current time to calculate absolute time of alarm */
 151         clock_gettime(CLOCK_TYPE_ID, &now);
 152
 153         new_alarm->cb_fn = cb_fn;
 154         new_alarm->cb_arg = cb_arg;
 155         new_alarm->time.tv_usec = ((now.tv_nsec / NS_PER_US) + us) % US_PER_S;
 156         new_alarm->time.tv_sec = now.tv_sec + (((now.tv_nsec / NS_PER_US) + us) / US_PER_S);
 157
 158         rte_spinlock_lock(&alarm_list_lk);
 159         if (!handler_registered) {
 160                 /* registration can fail, callback can be registered later */
 161                 if (rte_intr_callback_register(intr_handle,
 162                                 eal_alarm_callback, NULL) == 0)
 163                         handler_registered = 1;
 164         }
 165
 166         if (LIST_EMPTY(&alarm_list))
 167                 LIST_INSERT_HEAD(&alarm_list, new_alarm, next);
 168         else {
 169                 LIST_FOREACH(ap, &alarm_list, next) {
 170                         if (ap->time.tv_sec > new_alarm->time.tv_sec ||
 171                                         (ap->time.tv_sec == new_alarm->time.tv_sec &&
 172                                                         ap->time.tv_usec > new_alarm->time.tv_usec)){
 173                                 LIST_INSERT_BEFORE(ap, new_alarm, next);
 174                                 break;
 175                         }
 176                         if (LIST_NEXT(ap, next) == NULL) {
 177                                 LIST_INSERT_AFTER(ap, new_alarm, next);
 178                                 break;
 179                         }
 180                 }
 181         }
 182
 183         if (LIST_FIRST(&alarm_list) == new_alarm) {
 184                 struct itimerspec alarm_time = {
 185                         .it_interval = {0, 0},
 186                         .it_value = {
 187                                 .tv_sec = us / US_PER_S,
 188                                 .tv_nsec = (us % US_PER_S) * NS_PER_US,
 189                         },
 190                 };
 191                 ret |= timerfd_settime(rte_intr_fd_get(intr_handle), 0, &alarm_time, NULL);
 192         }
 193         rte_spinlock_unlock(&alarm_list_lk);
 194
 195         rte_eal_trace_alarm_set(us, cb_fn, cb_arg, ret);
 196         return ret;
 197 }
 198
 199 int
 200 rte_eal_alarm_cancel(rte_eal_alarm_callback cb_fn, void *cb_arg)
 201 {
 202         struct alarm_entry *ap, *ap_prev;
 203         int count = 0;
 204         int err = 0;
 205         int executing;
 206
 207         if (!cb_fn) {
 208                 rte_errno = EINVAL;
 209                 return -1;
 210         }
 211
 212         do {
 213                 executing = 0;
 214                 rte_spinlock_lock(&alarm_list_lk);
 215                 /* remove any matches at the start of the list */
 216                 while ((ap = LIST_FIRST(&alarm_list)) != NULL &&
 217                                 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                         } else {
 225                                 /* If calling from other context, mark that alarm is executing
 226                                  * so loop can spin till it finish. Otherwise we are trying to
 227                                  * cancel our self - mark it by EINPROGRESS */
 228                                 if (pthread_equal(ap->executing_id, pthread_self()) == 0)
 229                                         executing++;
 230                                 else
 231                                         err = EINPROGRESS;
 232
 233                                 break;
 234                         }
 235                 }
 236                 ap_prev = ap;
 237
 238                 /* now go through list, removing entries not at start */
 239                 LIST_FOREACH(ap, &alarm_list, next) {
 240                         /* this won't be true first time through */
 241                         if (cb_fn == ap->cb_fn &&
 242                                         (cb_arg == (void *)-1 || cb_arg == ap->cb_arg)) {
 243
 244                                 if (ap->executing == 0) {
 245                                         LIST_REMOVE(ap, next);
 246                                         free(ap);
 247                                         count++;
 248                                         ap = ap_prev;
 249                                 } else if (pthread_equal(ap->executing_id, pthread_self()) == 0)
 250                                         executing++;
 251                                 else
 252                                         err = EINPROGRESS;
 253                         }
 254                         ap_prev = ap;
 255                 }
 256                 rte_spinlock_unlock(&alarm_list_lk);
 257         } while (executing != 0);
 258
 259         if (count == 0 && err == 0)
 260                 rte_errno = ENOENT;
 261         else if (err)
 262                 rte_errno = err;
 263
 264         rte_eal_trace_alarm_cancel(cb_fn, cb_arg, count);
 265         return count;
 266 }