110817bf0SDaniel P. Berrange /*
210817bf0SDaniel P. Berrange * QEMU coroutine sleep
310817bf0SDaniel P. Berrange *
410817bf0SDaniel P. Berrange * Copyright IBM, Corp. 2011
510817bf0SDaniel P. Berrange *
610817bf0SDaniel P. Berrange * Authors:
710817bf0SDaniel P. Berrange * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
810817bf0SDaniel P. Berrange *
910817bf0SDaniel P. Berrange * This work is licensed under the terms of the GNU LGPL, version 2 or later.
1010817bf0SDaniel P. Berrange * See the COPYING.LIB file in the top-level directory.
1110817bf0SDaniel P. Berrange *
1210817bf0SDaniel P. Berrange */
1310817bf0SDaniel P. Berrange
14aafd7584SPeter Maydell #include "qemu/osdep.h"
156133b39fSJeff Cody #include "qemu/coroutine_int.h"
1610817bf0SDaniel P. Berrange #include "qemu/timer.h"
1710817bf0SDaniel P. Berrange #include "block/aio.h"
1810817bf0SDaniel P. Berrange
193d692649SVladimir Sementsov-Ogievskiy static const char *qemu_co_sleep_ns__scheduled = "qemu_co_sleep_ns";
2010817bf0SDaniel P. Berrange
qemu_co_sleep_wake(QemuCoSleep * w)2129a6ea24SPaolo Bonzini void qemu_co_sleep_wake(QemuCoSleep *w)
223d692649SVladimir Sementsov-Ogievskiy {
2329a6ea24SPaolo Bonzini Coroutine *co;
2429a6ea24SPaolo Bonzini
2529a6ea24SPaolo Bonzini co = w->to_wake;
2629a6ea24SPaolo Bonzini w->to_wake = NULL;
2729a6ea24SPaolo Bonzini if (co) {
286133b39fSJeff Cody /* Write of schedule protected by barrier write in aio_co_schedule */
2929a6ea24SPaolo Bonzini const char *scheduled = qatomic_cmpxchg(&co->scheduled,
303d692649SVladimir Sementsov-Ogievskiy qemu_co_sleep_ns__scheduled, NULL);
313d692649SVladimir Sementsov-Ogievskiy
323d692649SVladimir Sementsov-Ogievskiy assert(scheduled == qemu_co_sleep_ns__scheduled);
3329a6ea24SPaolo Bonzini aio_co_wake(co);
3410817bf0SDaniel P. Berrange }
35eaee0720SPaolo Bonzini }
3610817bf0SDaniel P. Berrange
co_sleep_cb(void * opaque)373d692649SVladimir Sementsov-Ogievskiy static void co_sleep_cb(void *opaque)
383d692649SVladimir Sementsov-Ogievskiy {
3929a6ea24SPaolo Bonzini QemuCoSleep *w = opaque;
4029a6ea24SPaolo Bonzini qemu_co_sleep_wake(w);
413d692649SVladimir Sementsov-Ogievskiy }
423d692649SVladimir Sementsov-Ogievskiy
qemu_co_sleep(QemuCoSleep * w)43*0a6f0c76SPaolo Bonzini void coroutine_fn qemu_co_sleep(QemuCoSleep *w)
4410817bf0SDaniel P. Berrange {
4529a6ea24SPaolo Bonzini Coroutine *co = qemu_coroutine_self();
466133b39fSJeff Cody
4729a6ea24SPaolo Bonzini const char *scheduled = qatomic_cmpxchg(&co->scheduled, NULL,
483d692649SVladimir Sementsov-Ogievskiy qemu_co_sleep_ns__scheduled);
496133b39fSJeff Cody if (scheduled) {
506133b39fSJeff Cody fprintf(stderr,
516133b39fSJeff Cody "%s: Co-routine was already scheduled in '%s'\n",
526133b39fSJeff Cody __func__, scheduled);
536133b39fSJeff Cody abort();
546133b39fSJeff Cody }
553d692649SVladimir Sementsov-Ogievskiy
5629a6ea24SPaolo Bonzini w->to_wake = co;
5710817bf0SDaniel P. Berrange qemu_coroutine_yield();
58fb74a286SPaolo Bonzini
5929a6ea24SPaolo Bonzini /* w->to_wake is cleared before resuming this coroutine. */
6029a6ea24SPaolo Bonzini assert(w->to_wake == NULL);
61f61ffad5SEric Blake }
62*0a6f0c76SPaolo Bonzini
qemu_co_sleep_ns_wakeable(QemuCoSleep * w,QEMUClockType type,int64_t ns)63*0a6f0c76SPaolo Bonzini void coroutine_fn qemu_co_sleep_ns_wakeable(QemuCoSleep *w,
64*0a6f0c76SPaolo Bonzini QEMUClockType type, int64_t ns)
65*0a6f0c76SPaolo Bonzini {
66*0a6f0c76SPaolo Bonzini AioContext *ctx = qemu_get_current_aio_context();
67*0a6f0c76SPaolo Bonzini QEMUTimer ts;
68*0a6f0c76SPaolo Bonzini
69*0a6f0c76SPaolo Bonzini aio_timer_init(ctx, &ts, type, SCALE_NS, co_sleep_cb, w);
70*0a6f0c76SPaolo Bonzini timer_mod(&ts, qemu_clock_get_ns(type) + ns);
71*0a6f0c76SPaolo Bonzini
72*0a6f0c76SPaolo Bonzini /*
73*0a6f0c76SPaolo Bonzini * The timer will fire in the current AiOContext, so the callback
74*0a6f0c76SPaolo Bonzini * must happen after qemu_co_sleep yields and there is no race
75*0a6f0c76SPaolo Bonzini * between timer_mod and qemu_co_sleep.
76*0a6f0c76SPaolo Bonzini */
77*0a6f0c76SPaolo Bonzini qemu_co_sleep(w);
78*0a6f0c76SPaolo Bonzini timer_del(&ts);
79*0a6f0c76SPaolo Bonzini }
80