Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 1 | /* |
| 2 | * QEMU coroutines |
| 3 | * |
| 4 | * Copyright IBM, Corp. 2011 |
| 5 | * |
| 6 | * Authors: |
| 7 | * Stefan Hajnoczi <stefanha@linux.vnet.ibm.com> |
| 8 | * Kevin Wolf <kwolf@redhat.com> |
| 9 | * |
| 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. |
| 12 | * |
| 13 | */ |
| 14 | |
Peter Maydell | aafd758 | 2016-01-29 17:49:55 +0000 | [diff] [blame] | 15 | #include "qemu/osdep.h" |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 16 | #include "trace.h" |
| 17 | #include "qemu-common.h" |
Stefan Hajnoczi | b84c458 | 2013-05-17 15:51:25 +0200 | [diff] [blame] | 18 | #include "qemu/thread.h" |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 19 | #include "qemu/atomic.h" |
Daniel P. Berrange | 10817bf | 2015-09-01 14:48:02 +0100 | [diff] [blame] | 20 | #include "qemu/coroutine.h" |
| 21 | #include "qemu/coroutine_int.h" |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 22 | |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 23 | enum { |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 24 | POOL_BATCH_SIZE = 64, |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 25 | }; |
| 26 | |
| 27 | /** Free list to speed up creation */ |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 28 | static QSLIST_HEAD(, Coroutine) release_pool = QSLIST_HEAD_INITIALIZER(pool); |
| 29 | static unsigned int release_pool_size; |
| 30 | static __thread QSLIST_HEAD(, Coroutine) alloc_pool = QSLIST_HEAD_INITIALIZER(pool); |
Peter Lieven | 51a2219 | 2014-12-02 12:05:50 +0100 | [diff] [blame] | 31 | static __thread unsigned int alloc_pool_size; |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 32 | static __thread Notifier coroutine_pool_cleanup_notifier; |
| 33 | |
| 34 | static void coroutine_pool_cleanup(Notifier *n, void *value) |
| 35 | { |
| 36 | Coroutine *co; |
| 37 | Coroutine *tmp; |
| 38 | |
| 39 | QSLIST_FOREACH_SAFE(co, &alloc_pool, pool_next, tmp) { |
| 40 | QSLIST_REMOVE_HEAD(&alloc_pool, pool_next); |
| 41 | qemu_coroutine_delete(co); |
| 42 | } |
| 43 | } |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 44 | |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 45 | Coroutine *qemu_coroutine_create(CoroutineEntry *entry) |
| 46 | { |
Stefan Hajnoczi | 70c60c0 | 2013-09-11 16:42:35 +0200 | [diff] [blame] | 47 | Coroutine *co = NULL; |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 48 | |
Stefan Hajnoczi | 70c60c0 | 2013-09-11 16:42:35 +0200 | [diff] [blame] | 49 | if (CONFIG_COROUTINE_POOL) { |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 50 | co = QSLIST_FIRST(&alloc_pool); |
| 51 | if (!co) { |
| 52 | if (release_pool_size > POOL_BATCH_SIZE) { |
| 53 | /* Slow path; a good place to register the destructor, too. */ |
| 54 | if (!coroutine_pool_cleanup_notifier.notify) { |
| 55 | coroutine_pool_cleanup_notifier.notify = coroutine_pool_cleanup; |
| 56 | qemu_thread_atexit_add(&coroutine_pool_cleanup_notifier); |
| 57 | } |
| 58 | |
| 59 | /* This is not exact; there could be a little skew between |
| 60 | * release_pool_size and the actual size of release_pool. But |
| 61 | * it is just a heuristic, it does not need to be perfect. |
| 62 | */ |
Peter Lieven | 51a2219 | 2014-12-02 12:05:50 +0100 | [diff] [blame] | 63 | alloc_pool_size = atomic_xchg(&release_pool_size, 0); |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 64 | QSLIST_MOVE_ATOMIC(&alloc_pool, &release_pool); |
| 65 | co = QSLIST_FIRST(&alloc_pool); |
| 66 | } |
Stefan Hajnoczi | 70c60c0 | 2013-09-11 16:42:35 +0200 | [diff] [blame] | 67 | } |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 68 | if (co) { |
| 69 | QSLIST_REMOVE_HEAD(&alloc_pool, pool_next); |
Peter Lieven | 51a2219 | 2014-12-02 12:05:50 +0100 | [diff] [blame] | 70 | alloc_pool_size--; |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 71 | } |
Stefan Hajnoczi | b84c458 | 2013-05-17 15:51:25 +0200 | [diff] [blame] | 72 | } |
Stefan Hajnoczi | b84c458 | 2013-05-17 15:51:25 +0200 | [diff] [blame] | 73 | |
| 74 | if (!co) { |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 75 | co = qemu_coroutine_new(); |
| 76 | } |
| 77 | |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 78 | co->entry = entry; |
Stefan Hajnoczi | 02ffb50 | 2013-05-17 15:51:26 +0200 | [diff] [blame] | 79 | QTAILQ_INIT(&co->co_queue_wakeup); |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 80 | return co; |
| 81 | } |
| 82 | |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 83 | static void coroutine_delete(Coroutine *co) |
| 84 | { |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 85 | co->caller = NULL; |
| 86 | |
Stefan Hajnoczi | 70c60c0 | 2013-09-11 16:42:35 +0200 | [diff] [blame] | 87 | if (CONFIG_COROUTINE_POOL) { |
Paolo Bonzini | 4d68e86 | 2014-12-02 12:05:48 +0100 | [diff] [blame] | 88 | if (release_pool_size < POOL_BATCH_SIZE * 2) { |
| 89 | QSLIST_INSERT_HEAD_ATOMIC(&release_pool, co, pool_next); |
| 90 | atomic_inc(&release_pool_size); |
Stefan Hajnoczi | 70c60c0 | 2013-09-11 16:42:35 +0200 | [diff] [blame] | 91 | return; |
| 92 | } |
Peter Lieven | 51a2219 | 2014-12-02 12:05:50 +0100 | [diff] [blame] | 93 | if (alloc_pool_size < POOL_BATCH_SIZE) { |
| 94 | QSLIST_INSERT_HEAD(&alloc_pool, co, pool_next); |
| 95 | alloc_pool_size++; |
| 96 | return; |
| 97 | } |
Paolo Bonzini | 4023978 | 2013-02-19 11:59:09 +0100 | [diff] [blame] | 98 | } |
| 99 | |
| 100 | qemu_coroutine_delete(co); |
| 101 | } |
| 102 | |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 103 | void qemu_coroutine_enter(Coroutine *co, void *opaque) |
| 104 | { |
| 105 | Coroutine *self = qemu_coroutine_self(); |
Kevin Wolf | cd12bb5 | 2015-02-10 11:31:52 +0100 | [diff] [blame] | 106 | CoroutineAction ret; |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 107 | |
| 108 | trace_qemu_coroutine_enter(self, co, opaque); |
| 109 | |
| 110 | if (co->caller) { |
| 111 | fprintf(stderr, "Co-routine re-entered recursively\n"); |
| 112 | abort(); |
| 113 | } |
| 114 | |
| 115 | co->caller = self; |
| 116 | co->entry_arg = opaque; |
Kevin Wolf | cd12bb5 | 2015-02-10 11:31:52 +0100 | [diff] [blame] | 117 | ret = qemu_coroutine_switch(self, co, COROUTINE_ENTER); |
| 118 | |
| 119 | qemu_co_queue_run_restart(co); |
| 120 | |
| 121 | switch (ret) { |
| 122 | case COROUTINE_YIELD: |
| 123 | return; |
| 124 | case COROUTINE_TERMINATE: |
| 125 | trace_qemu_coroutine_terminate(co); |
| 126 | coroutine_delete(co); |
| 127 | return; |
| 128 | default: |
| 129 | abort(); |
| 130 | } |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | void coroutine_fn qemu_coroutine_yield(void) |
| 134 | { |
| 135 | Coroutine *self = qemu_coroutine_self(); |
| 136 | Coroutine *to = self->caller; |
| 137 | |
| 138 | trace_qemu_coroutine_yield(self, to); |
| 139 | |
| 140 | if (!to) { |
| 141 | fprintf(stderr, "Co-routine is yielding to no one\n"); |
| 142 | abort(); |
| 143 | } |
| 144 | |
| 145 | self->caller = NULL; |
Kevin Wolf | 315a130 | 2015-02-10 11:17:53 +0100 | [diff] [blame] | 146 | qemu_coroutine_switch(self, to, COROUTINE_YIELD); |
Kevin Wolf | 00dccaf | 2011-01-17 16:08:14 +0000 | [diff] [blame] | 147 | } |