coroutine: switch per-thread free pool to a global pool
ucontext-based coroutines use a free pool to reduce allocations and deallocations of coroutine objects. The pool is per-thread, presumably to improve locality. However, as coroutines are usually allocated in a vcpu thread and freed in the I/O thread, the pool accounting gets screwed up and we end allocating and freeing a coroutine for every I/O request. This is expensive since large objects are allocated via the kernel, and are not cached by the C runtime. Fix by switching to a global pool. This is safe since we're protected by the global mutex. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
parent
c2c9a46609
commit
39a7a362e1
@ -35,6 +35,10 @@ enum {
|
|||||||
POOL_MAX_SIZE = 64,
|
POOL_MAX_SIZE = 64,
|
||||||
};
|
};
|
||||||
|
|
||||||
|
/** Free list to speed up creation */
|
||||||
|
static QLIST_HEAD(, Coroutine) pool = QLIST_HEAD_INITIALIZER(pool);
|
||||||
|
static unsigned int pool_size;
|
||||||
|
|
||||||
typedef struct {
|
typedef struct {
|
||||||
Coroutine base;
|
Coroutine base;
|
||||||
void *stack;
|
void *stack;
|
||||||
@ -48,10 +52,6 @@ typedef struct {
|
|||||||
/** Currently executing coroutine */
|
/** Currently executing coroutine */
|
||||||
Coroutine *current;
|
Coroutine *current;
|
||||||
|
|
||||||
/** Free list to speed up creation */
|
|
||||||
QLIST_HEAD(, Coroutine) pool;
|
|
||||||
unsigned int pool_size;
|
|
||||||
|
|
||||||
/** The default coroutine */
|
/** The default coroutine */
|
||||||
CoroutineUContext leader;
|
CoroutineUContext leader;
|
||||||
} CoroutineThreadState;
|
} CoroutineThreadState;
|
||||||
@ -75,7 +75,6 @@ static CoroutineThreadState *coroutine_get_thread_state(void)
|
|||||||
if (!s) {
|
if (!s) {
|
||||||
s = g_malloc0(sizeof(*s));
|
s = g_malloc0(sizeof(*s));
|
||||||
s->current = &s->leader.base;
|
s->current = &s->leader.base;
|
||||||
QLIST_INIT(&s->pool);
|
|
||||||
pthread_setspecific(thread_state_key, s);
|
pthread_setspecific(thread_state_key, s);
|
||||||
}
|
}
|
||||||
return s;
|
return s;
|
||||||
@ -84,14 +83,19 @@ static CoroutineThreadState *coroutine_get_thread_state(void)
|
|||||||
static void qemu_coroutine_thread_cleanup(void *opaque)
|
static void qemu_coroutine_thread_cleanup(void *opaque)
|
||||||
{
|
{
|
||||||
CoroutineThreadState *s = opaque;
|
CoroutineThreadState *s = opaque;
|
||||||
|
|
||||||
|
g_free(s);
|
||||||
|
}
|
||||||
|
|
||||||
|
static void __attribute__((destructor)) coroutine_cleanup(void)
|
||||||
|
{
|
||||||
Coroutine *co;
|
Coroutine *co;
|
||||||
Coroutine *tmp;
|
Coroutine *tmp;
|
||||||
|
|
||||||
QLIST_FOREACH_SAFE(co, &s->pool, pool_next, tmp) {
|
QLIST_FOREACH_SAFE(co, &pool, pool_next, tmp) {
|
||||||
g_free(DO_UPCAST(CoroutineUContext, base, co)->stack);
|
g_free(DO_UPCAST(CoroutineUContext, base, co)->stack);
|
||||||
g_free(co);
|
g_free(co);
|
||||||
}
|
}
|
||||||
g_free(s);
|
|
||||||
}
|
}
|
||||||
|
|
||||||
static void __attribute__((constructor)) coroutine_init(void)
|
static void __attribute__((constructor)) coroutine_init(void)
|
||||||
@ -169,13 +173,12 @@ static Coroutine *coroutine_new(void)
|
|||||||
|
|
||||||
Coroutine *qemu_coroutine_new(void)
|
Coroutine *qemu_coroutine_new(void)
|
||||||
{
|
{
|
||||||
CoroutineThreadState *s = coroutine_get_thread_state();
|
|
||||||
Coroutine *co;
|
Coroutine *co;
|
||||||
|
|
||||||
co = QLIST_FIRST(&s->pool);
|
co = QLIST_FIRST(&pool);
|
||||||
if (co) {
|
if (co) {
|
||||||
QLIST_REMOVE(co, pool_next);
|
QLIST_REMOVE(co, pool_next);
|
||||||
s->pool_size--;
|
pool_size--;
|
||||||
} else {
|
} else {
|
||||||
co = coroutine_new();
|
co = coroutine_new();
|
||||||
}
|
}
|
||||||
@ -184,13 +187,12 @@ Coroutine *qemu_coroutine_new(void)
|
|||||||
|
|
||||||
void qemu_coroutine_delete(Coroutine *co_)
|
void qemu_coroutine_delete(Coroutine *co_)
|
||||||
{
|
{
|
||||||
CoroutineThreadState *s = coroutine_get_thread_state();
|
|
||||||
CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_);
|
CoroutineUContext *co = DO_UPCAST(CoroutineUContext, base, co_);
|
||||||
|
|
||||||
if (s->pool_size < POOL_MAX_SIZE) {
|
if (pool_size < POOL_MAX_SIZE) {
|
||||||
QLIST_INSERT_HEAD(&s->pool, &co->base, pool_next);
|
QLIST_INSERT_HEAD(&pool, &co->base, pool_next);
|
||||||
co->base.caller = NULL;
|
co->base.caller = NULL;
|
||||||
s->pool_size++;
|
pool_size++;
|
||||||
return;
|
return;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
Loading…
Reference in New Issue
Block a user