4 * Copyright IBM, Corp. 2011
7 * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
8 * Kevin Wolf <kwolf@redhat.com>
10 * This work is licensed under the terms of the GNU LGPL, version 2 or later.
11 * See the COPYING.LIB file in the top-level directory.
16 #include "qemu-common.h"
17 #include "qemu/thread.h"
18 #include "qemu/atomic.h"
19 #include "block/coroutine.h"
20 #include "block/coroutine_int.h"
26 /** Free list to speed up creation */
27 static QSLIST_HEAD(, Coroutine
) release_pool
= QSLIST_HEAD_INITIALIZER(pool
);
28 static unsigned int release_pool_size
;
29 static __thread
QSLIST_HEAD(, Coroutine
) alloc_pool
= QSLIST_HEAD_INITIALIZER(pool
);
30 static __thread Notifier coroutine_pool_cleanup_notifier
;
32 static void coroutine_pool_cleanup(Notifier
*n
, void *value
)
37 QSLIST_FOREACH_SAFE(co
, &alloc_pool
, pool_next
, tmp
) {
38 QSLIST_REMOVE_HEAD(&alloc_pool
, pool_next
);
39 qemu_coroutine_delete(co
);
43 Coroutine
*qemu_coroutine_create(CoroutineEntry
*entry
)
47 if (CONFIG_COROUTINE_POOL
) {
48 co
= QSLIST_FIRST(&alloc_pool
);
50 if (release_pool_size
> POOL_BATCH_SIZE
) {
51 /* Slow path; a good place to register the destructor, too. */
52 if (!coroutine_pool_cleanup_notifier
.notify
) {
53 coroutine_pool_cleanup_notifier
.notify
= coroutine_pool_cleanup
;
54 qemu_thread_atexit_add(&coroutine_pool_cleanup_notifier
);
57 /* This is not exact; there could be a little skew between
58 * release_pool_size and the actual size of release_pool. But
59 * it is just a heuristic, it does not need to be perfect.
61 release_pool_size
= 0;
62 QSLIST_MOVE_ATOMIC(&alloc_pool
, &release_pool
);
63 co
= QSLIST_FIRST(&alloc_pool
);
67 QSLIST_REMOVE_HEAD(&alloc_pool
, pool_next
);
72 co
= qemu_coroutine_new();
76 QTAILQ_INIT(&co
->co_queue_wakeup
);
80 static void coroutine_delete(Coroutine
*co
)
84 if (CONFIG_COROUTINE_POOL
) {
85 if (release_pool_size
< POOL_BATCH_SIZE
* 2) {
86 QSLIST_INSERT_HEAD_ATOMIC(&release_pool
, co
, pool_next
);
87 atomic_inc(&release_pool_size
);
92 qemu_coroutine_delete(co
);
95 static void coroutine_swap(Coroutine
*from
, Coroutine
*to
)
99 ret
= qemu_coroutine_switch(from
, to
, COROUTINE_YIELD
);
101 qemu_co_queue_run_restart(to
);
104 case COROUTINE_YIELD
:
106 case COROUTINE_TERMINATE
:
107 trace_qemu_coroutine_terminate(to
);
108 coroutine_delete(to
);
115 void qemu_coroutine_enter(Coroutine
*co
, void *opaque
)
117 Coroutine
*self
= qemu_coroutine_self();
119 trace_qemu_coroutine_enter(self
, co
, opaque
);
122 fprintf(stderr
, "Co-routine re-entered recursively\n");
127 co
->entry_arg
= opaque
;
128 coroutine_swap(self
, co
);
131 void coroutine_fn
qemu_coroutine_yield(void)
133 Coroutine
*self
= qemu_coroutine_self();
134 Coroutine
*to
= self
->caller
;
136 trace_qemu_coroutine_yield(self
, to
);
139 fprintf(stderr
, "Co-routine is yielding to no one\n");
144 coroutine_swap(self
, to
);
147 void qemu_coroutine_adjust_pool_size(int n
)