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Diffstat (limited to 'util/coroutine-gthread.c')
| -rw-r--r-- | util/coroutine-gthread.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/util/coroutine-gthread.c b/util/coroutine-gthread.c new file mode 100644 index 0000000000..0bcd77867d --- /dev/null +++ b/util/coroutine-gthread.c @@ -0,0 +1,198 @@ +/* + * GThread coroutine initialization code + * + * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws> + * Copyright (C) 2011 Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.0 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, see <http://www.gnu.org/licenses/>. + */ + +#include <glib.h> +#include "qemu-common.h" +#include "qemu/coroutine_int.h" + +typedef struct { + Coroutine base; + GThread *thread; + bool runnable; + bool free_on_thread_exit; + CoroutineAction action; +} CoroutineGThread; + +static CompatGMutex coroutine_lock; +static CompatGCond coroutine_cond; + +/* GLib 2.31 and beyond deprecated various parts of the thread API, + * but the new interfaces are not available in older GLib versions + * so we have to cope with both. + */ +#if GLIB_CHECK_VERSION(2, 31, 0) +/* Awkwardly, the GPrivate API doesn't provide a way to update the + * GDestroyNotify handler for the coroutine key dynamically. So instead + * we track whether or not the CoroutineGThread should be freed on + * thread exit / coroutine key update using the free_on_thread_exit + * field. + */ +static void coroutine_destroy_notify(gpointer data) +{ + CoroutineGThread *co = data; + if (co && co->free_on_thread_exit) { + g_free(co); + } +} + +static GPrivate coroutine_key = G_PRIVATE_INIT(coroutine_destroy_notify); + +static inline CoroutineGThread *get_coroutine_key(void) +{ + return g_private_get(&coroutine_key); +} + +static inline void set_coroutine_key(CoroutineGThread *co, + bool free_on_thread_exit) +{ + /* Unlike g_static_private_set() this does not call the GDestroyNotify + * if the previous value of the key was NULL. Fortunately we only need + * the GDestroyNotify in the non-NULL key case. + */ + co->free_on_thread_exit = free_on_thread_exit; + g_private_replace(&coroutine_key, co); +} + +static inline GThread *create_thread(GThreadFunc func, gpointer data) +{ + return g_thread_new("coroutine", func, data); +} + +#else + +/* Handle older GLib versions */ + +static GStaticPrivate coroutine_key = G_STATIC_PRIVATE_INIT; + +static inline CoroutineGThread *get_coroutine_key(void) +{ + return g_static_private_get(&coroutine_key); +} + +static inline void set_coroutine_key(CoroutineGThread *co, + bool free_on_thread_exit) +{ + g_static_private_set(&coroutine_key, co, + free_on_thread_exit ? (GDestroyNotify)g_free : NULL); +} + +static inline GThread *create_thread(GThreadFunc func, gpointer data) +{ + return g_thread_create_full(func, data, 0, TRUE, TRUE, + G_THREAD_PRIORITY_NORMAL, NULL); +} + +#endif + + +static void __attribute__((constructor)) coroutine_init(void) +{ +#if !GLIB_CHECK_VERSION(2, 31, 0) + if (!g_thread_supported()) { + g_thread_init(NULL); + } +#endif +} + +static void coroutine_wait_runnable_locked(CoroutineGThread *co) +{ + while (!co->runnable) { + g_cond_wait(&coroutine_cond, &coroutine_lock); + } +} + +static void coroutine_wait_runnable(CoroutineGThread *co) +{ + g_mutex_lock(&coroutine_lock); + coroutine_wait_runnable_locked(co); + g_mutex_unlock(&coroutine_lock); +} + +static gpointer coroutine_thread(gpointer opaque) +{ + CoroutineGThread *co = opaque; + + set_coroutine_key(co, false); + coroutine_wait_runnable(co); + co->base.entry(co->base.entry_arg); + qemu_coroutine_switch(&co->base, co->base.caller, COROUTINE_TERMINATE); + return NULL; +} + +Coroutine *qemu_coroutine_new(void) +{ + CoroutineGThread *co; + + co = g_malloc0(sizeof(*co)); + co->thread = create_thread(coroutine_thread, co); + if (!co->thread) { + g_free(co); + return NULL; + } + return &co->base; +} + +void qemu_coroutine_delete(Coroutine *co_) +{ + CoroutineGThread *co = DO_UPCAST(CoroutineGThread, base, co_); + + g_thread_join(co->thread); + g_free(co); +} + +CoroutineAction qemu_coroutine_switch(Coroutine *from_, + Coroutine *to_, + CoroutineAction action) +{ + CoroutineGThread *from = DO_UPCAST(CoroutineGThread, base, from_); + CoroutineGThread *to = DO_UPCAST(CoroutineGThread, base, to_); + + g_mutex_lock(&coroutine_lock); + from->runnable = false; + from->action = action; + to->runnable = true; + to->action = action; + g_cond_broadcast(&coroutine_cond); + + if (action != COROUTINE_TERMINATE) { + coroutine_wait_runnable_locked(from); + } + g_mutex_unlock(&coroutine_lock); + return from->action; +} + +Coroutine *qemu_coroutine_self(void) +{ + CoroutineGThread *co = get_coroutine_key(); + if (!co) { + co = g_malloc0(sizeof(*co)); + co->runnable = true; + set_coroutine_key(co, true); + } + + return &co->base; +} + +bool qemu_in_coroutine(void) +{ + CoroutineGThread *co = get_coroutine_key(); + + return co && co->base.caller; +} |