LXR qemu/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
  20static 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
  29void 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}
  48