util/qemu-coroutine-sleep.c

   1 /*
   2  * QEMU coroutine sleep
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Stefan Hajnoczi    <stefanha@linux.vnet.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  10  * See the COPYING.LIB file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu/osdep.h"
  15 #include "qemu/coroutine.h"
  16 #include "qemu/coroutine_int.h"
  17 #include "qemu/timer.h"
  18 #include "block/aio.h"
  19
  20 static void co_sleep_cb(void *opaque)
  21 {
  22     Coroutine *co = opaque;
  23
  24     /* Write of schedule protected by barrier write in aio_co_schedule */
  25     atomic_set(&co->scheduled, NULL);
  26     aio_co_wake(co);
  27 }
  28
  29 void coroutine_fn qemu_co_sleep_ns(QEMUClockType type, int64_t ns)
  30 {
  31     AioContext *ctx = qemu_get_current_aio_context();
  32     QEMUTimer *ts;
  33     Coroutine *co = qemu_coroutine_self();
  34
  35     const char *scheduled = atomic_cmpxchg(&co->scheduled, NULL, __func__);
  36     if (scheduled) {
  37         fprintf(stderr,
  38                 "%s: Co-routine was already scheduled in '%s'\n",
  39                 __func__, scheduled);
  40         abort();
  41     }
  42     ts = aio_timer_new(ctx, type, SCALE_NS, co_sleep_cb, co);
  43     timer_mod(ts, qemu_clock_get_ns(type) + ns);
  44     qemu_coroutine_yield();
  45     timer_del(ts);
  46     timer_free(ts);
  47 }