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glib-compat.h: add new thread API emulation on top of pre-2.31 API

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Thread API changed in glib-2.31 significantly.  Before that version,
conditionals and mutexes were only allocated dynamically, using
_new()/_free() interface.  in 2.31 and up, they're allocated statically
as regular variables, and old interface is deprecated.

(Note: glib docs says the new interface is available since version
2.32, but it was actually introduced in version 2.31).

Create the new interface using old primitives, by providing non-opaque
definitions of the base types (GCond and GMutex) using GOnces.

Replace #ifdeffery around GCond and GMutex in trace/simple.c and
coroutine-gthread.c too because it does not work anymore with the new
glib-compat.h.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[Use GOnce to support lazy initialization; introduce CompatGMutex
 and CompatGCond.  - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Michael Tokarev 2014-05-08 12:30:46 +04:00 • committed by Paolo Bonzini
parent 7721a30442
commit 86946a2d83
3 changed files with 138 additions and 60 deletions
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29
coroutine-gthread.c
View file

@ -30,20 +30,14 @@ typedef struct {
CoroutineAction action;
} CoroutineGThread;
static GStaticMutex coroutine_lock = G_STATIC_MUTEX_INIT;
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)
/* Default zero-initialisation is sufficient for 2.31+ GCond */
static GCond the_coroutine_cond;
static GCond *coroutine_cond = &the_coroutine_cond;
static inline void init_coroutine_cond(void)
{
}
/* 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
@ -84,11 +78,6 @@ static inline GThread *create_thread(GThreadFunc func, gpointer data)
#else
/* Handle older GLib versions */
static GCond *coroutine_cond;
static inline void init_coroutine_cond(void)
{
coroutine_cond = g_cond_new();
}
static GStaticPrivate coroutine_key = G_STATIC_PRIVATE_INIT;
@ -120,22 +109,20 @@ static void __attribute__((constructor)) coroutine_init(void)
g_thread_init(NULL);
}
#endif
init_coroutine_cond();
}
static void coroutine_wait_runnable_locked(CoroutineGThread *co)
{
while (!co->runnable) {
g_cond_wait(coroutine_cond, g_static_mutex_get_mutex(&coroutine_lock));
g_cond_wait(&coroutine_cond, &coroutine_lock);
}
}
static void coroutine_wait_runnable(CoroutineGThread *co)
{
g_static_mutex_lock(&coroutine_lock);
g_mutex_lock(&coroutine_lock);
coroutine_wait_runnable_locked(co);
g_static_mutex_unlock(&coroutine_lock);
g_mutex_unlock(&coroutine_lock);
}
static gpointer coroutine_thread(gpointer opaque)
@ -177,17 +164,17 @@ CoroutineAction qemu_coroutine_switch(Coroutine *from_,
CoroutineGThread *from = DO_UPCAST(CoroutineGThread, base, from_);
CoroutineGThread *to = DO_UPCAST(CoroutineGThread, base, to_);
g_static_mutex_lock(&coroutine_lock);
g_mutex_lock(&coroutine_lock);
from->runnable = false;
from->action = action;
to->runnable = true;
to->action = action;
g_cond_broadcast(coroutine_cond);
g_cond_broadcast(&coroutine_cond);
if (action != COROUTINE_TERMINATE) {
coroutine_wait_runnable_locked(from);
}
g_static_mutex_unlock(&coroutine_lock);
g_mutex_unlock(&coroutine_lock);
return from->action;
}