root / qemu-coroutine.c @ f53ec699
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1 | 00dccaf1 | Kevin Wolf | /*
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2 | 00dccaf1 | Kevin Wolf | * QEMU coroutines
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3 | 00dccaf1 | Kevin Wolf | *
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4 | 00dccaf1 | Kevin Wolf | * Copyright IBM, Corp. 2011
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5 | 00dccaf1 | Kevin Wolf | *
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6 | 00dccaf1 | Kevin Wolf | * Authors:
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7 | 00dccaf1 | Kevin Wolf | * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
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8 | 00dccaf1 | Kevin Wolf | * Kevin Wolf <kwolf@redhat.com>
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9 | 00dccaf1 | Kevin Wolf | *
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10 | 00dccaf1 | Kevin Wolf | * This work is licensed under the terms of the GNU LGPL, version 2 or later.
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11 | 00dccaf1 | Kevin Wolf | * See the COPYING.LIB file in the top-level directory.
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12 | 00dccaf1 | Kevin Wolf | *
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13 | 00dccaf1 | Kevin Wolf | */
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14 | 00dccaf1 | Kevin Wolf | |
15 | 00dccaf1 | Kevin Wolf | #include "trace.h" |
16 | 00dccaf1 | Kevin Wolf | #include "qemu-common.h" |
17 | b84c4586 | Stefan Hajnoczi | #include "qemu/thread.h" |
18 | 737e150e | Paolo Bonzini | #include "block/coroutine.h" |
19 | 737e150e | Paolo Bonzini | #include "block/coroutine_int.h" |
20 | 00dccaf1 | Kevin Wolf | |
21 | 40239784 | Paolo Bonzini | enum {
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22 | 40239784 | Paolo Bonzini | /* Maximum free pool size prevents holding too many freed coroutines */
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23 | 40239784 | Paolo Bonzini | POOL_MAX_SIZE = 64,
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24 | 40239784 | Paolo Bonzini | }; |
25 | 40239784 | Paolo Bonzini | |
26 | 40239784 | Paolo Bonzini | /** Free list to speed up creation */
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27 | b84c4586 | Stefan Hajnoczi | static QemuMutex pool_lock;
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28 | 40239784 | Paolo Bonzini | static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
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29 | 40239784 | Paolo Bonzini | static unsigned int pool_size; |
30 | 40239784 | Paolo Bonzini | |
31 | 00dccaf1 | Kevin Wolf | Coroutine *qemu_coroutine_create(CoroutineEntry *entry) |
32 | 00dccaf1 | Kevin Wolf | { |
33 | 40239784 | Paolo Bonzini | Coroutine *co; |
34 | 40239784 | Paolo Bonzini | |
35 | b84c4586 | Stefan Hajnoczi | qemu_mutex_lock(&pool_lock); |
36 | 40239784 | Paolo Bonzini | co = QSLIST_FIRST(&pool); |
37 | 40239784 | Paolo Bonzini | if (co) {
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38 | 40239784 | Paolo Bonzini | QSLIST_REMOVE_HEAD(&pool, pool_next); |
39 | 40239784 | Paolo Bonzini | pool_size--; |
40 | b84c4586 | Stefan Hajnoczi | } |
41 | b84c4586 | Stefan Hajnoczi | qemu_mutex_unlock(&pool_lock); |
42 | b84c4586 | Stefan Hajnoczi | |
43 | b84c4586 | Stefan Hajnoczi | if (!co) {
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44 | 40239784 | Paolo Bonzini | co = qemu_coroutine_new(); |
45 | 40239784 | Paolo Bonzini | } |
46 | 40239784 | Paolo Bonzini | |
47 | 00dccaf1 | Kevin Wolf | co->entry = entry; |
48 | 02ffb504 | Stefan Hajnoczi | QTAILQ_INIT(&co->co_queue_wakeup); |
49 | 00dccaf1 | Kevin Wolf | return co;
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50 | 00dccaf1 | Kevin Wolf | } |
51 | 00dccaf1 | Kevin Wolf | |
52 | 40239784 | Paolo Bonzini | static void coroutine_delete(Coroutine *co) |
53 | 40239784 | Paolo Bonzini | { |
54 | b84c4586 | Stefan Hajnoczi | qemu_mutex_lock(&pool_lock); |
55 | 40239784 | Paolo Bonzini | if (pool_size < POOL_MAX_SIZE) {
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56 | 40239784 | Paolo Bonzini | QSLIST_INSERT_HEAD(&pool, co, pool_next); |
57 | 40239784 | Paolo Bonzini | co->caller = NULL;
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58 | 40239784 | Paolo Bonzini | pool_size++; |
59 | b84c4586 | Stefan Hajnoczi | qemu_mutex_unlock(&pool_lock); |
60 | 40239784 | Paolo Bonzini | return;
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61 | 40239784 | Paolo Bonzini | } |
62 | b84c4586 | Stefan Hajnoczi | qemu_mutex_unlock(&pool_lock); |
63 | 40239784 | Paolo Bonzini | |
64 | 40239784 | Paolo Bonzini | qemu_coroutine_delete(co); |
65 | 40239784 | Paolo Bonzini | } |
66 | 40239784 | Paolo Bonzini | |
67 | b84c4586 | Stefan Hajnoczi | static void __attribute__((constructor)) coroutine_pool_init(void) |
68 | b84c4586 | Stefan Hajnoczi | { |
69 | b84c4586 | Stefan Hajnoczi | qemu_mutex_init(&pool_lock); |
70 | b84c4586 | Stefan Hajnoczi | } |
71 | b84c4586 | Stefan Hajnoczi | |
72 | b84c4586 | Stefan Hajnoczi | static void __attribute__((destructor)) coroutine_pool_cleanup(void) |
73 | 40239784 | Paolo Bonzini | { |
74 | 40239784 | Paolo Bonzini | Coroutine *co; |
75 | 40239784 | Paolo Bonzini | Coroutine *tmp; |
76 | 40239784 | Paolo Bonzini | |
77 | 40239784 | Paolo Bonzini | QSLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) { |
78 | 40239784 | Paolo Bonzini | QSLIST_REMOVE_HEAD(&pool, pool_next); |
79 | 40239784 | Paolo Bonzini | qemu_coroutine_delete(co); |
80 | 40239784 | Paolo Bonzini | } |
81 | b84c4586 | Stefan Hajnoczi | |
82 | b84c4586 | Stefan Hajnoczi | qemu_mutex_destroy(&pool_lock); |
83 | 40239784 | Paolo Bonzini | } |
84 | 40239784 | Paolo Bonzini | |
85 | 00dccaf1 | Kevin Wolf | static void coroutine_swap(Coroutine *from, Coroutine *to) |
86 | 00dccaf1 | Kevin Wolf | { |
87 | 00dccaf1 | Kevin Wolf | CoroutineAction ret; |
88 | 00dccaf1 | Kevin Wolf | |
89 | 00dccaf1 | Kevin Wolf | ret = qemu_coroutine_switch(from, to, COROUTINE_YIELD); |
90 | 00dccaf1 | Kevin Wolf | |
91 | 02ffb504 | Stefan Hajnoczi | qemu_co_queue_run_restart(to); |
92 | 02ffb504 | Stefan Hajnoczi | |
93 | 00dccaf1 | Kevin Wolf | switch (ret) {
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94 | 00dccaf1 | Kevin Wolf | case COROUTINE_YIELD:
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95 | 00dccaf1 | Kevin Wolf | return;
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96 | 00dccaf1 | Kevin Wolf | case COROUTINE_TERMINATE:
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97 | 00dccaf1 | Kevin Wolf | trace_qemu_coroutine_terminate(to); |
98 | 40239784 | Paolo Bonzini | coroutine_delete(to); |
99 | 00dccaf1 | Kevin Wolf | return;
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100 | 00dccaf1 | Kevin Wolf | default:
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101 | 00dccaf1 | Kevin Wolf | abort(); |
102 | 00dccaf1 | Kevin Wolf | } |
103 | 00dccaf1 | Kevin Wolf | } |
104 | 00dccaf1 | Kevin Wolf | |
105 | 00dccaf1 | Kevin Wolf | void qemu_coroutine_enter(Coroutine *co, void *opaque) |
106 | 00dccaf1 | Kevin Wolf | { |
107 | 00dccaf1 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
108 | 00dccaf1 | Kevin Wolf | |
109 | 00dccaf1 | Kevin Wolf | trace_qemu_coroutine_enter(self, co, opaque); |
110 | 00dccaf1 | Kevin Wolf | |
111 | 00dccaf1 | Kevin Wolf | if (co->caller) {
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112 | 00dccaf1 | Kevin Wolf | fprintf(stderr, "Co-routine re-entered recursively\n");
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113 | 00dccaf1 | Kevin Wolf | abort(); |
114 | 00dccaf1 | Kevin Wolf | } |
115 | 00dccaf1 | Kevin Wolf | |
116 | 00dccaf1 | Kevin Wolf | co->caller = self; |
117 | 00dccaf1 | Kevin Wolf | co->entry_arg = opaque; |
118 | 00dccaf1 | Kevin Wolf | coroutine_swap(self, co); |
119 | 00dccaf1 | Kevin Wolf | } |
120 | 00dccaf1 | Kevin Wolf | |
121 | 00dccaf1 | Kevin Wolf | void coroutine_fn qemu_coroutine_yield(void) |
122 | 00dccaf1 | Kevin Wolf | { |
123 | 00dccaf1 | Kevin Wolf | Coroutine *self = qemu_coroutine_self(); |
124 | 00dccaf1 | Kevin Wolf | Coroutine *to = self->caller; |
125 | 00dccaf1 | Kevin Wolf | |
126 | 00dccaf1 | Kevin Wolf | trace_qemu_coroutine_yield(self, to); |
127 | 00dccaf1 | Kevin Wolf | |
128 | 00dccaf1 | Kevin Wolf | if (!to) {
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129 | 00dccaf1 | Kevin Wolf | fprintf(stderr, "Co-routine is yielding to no one\n");
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130 | 00dccaf1 | Kevin Wolf | abort(); |
131 | 00dccaf1 | Kevin Wolf | } |
132 | 00dccaf1 | Kevin Wolf | |
133 | 00dccaf1 | Kevin Wolf | self->caller = NULL;
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134 | 00dccaf1 | Kevin Wolf | coroutine_swap(self, to); |
135 | 00dccaf1 | Kevin Wolf | } |