From: Hao Xu <howeyxu@xxxxxxxxxxx>
When unregister fixed workers, there should be a way to allow us to wait
all the fixed workers exit.
Signed-off-by: Hao Xu <howeyxu@xxxxxxxxxxx>
---
io_uring/io-wq.c | 72 ++++++++++++++++++++++++++++++++++--------------
1 file changed, 52 insertions(+), 20 deletions(-)
diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
index f39e6b931d17..61cf6da2c72f 100644
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
@@ -108,6 +108,10 @@ struct io_wq {
atomic_t worker_refs;
struct completion worker_done;
+ atomic_t fixed_worker_refs;
+ struct completion fixed_worker_done;
+ bool fixed_comp_init;
+
struct hlist_node cpuhp_node;
struct task_struct *task;
@@ -172,10 +176,25 @@ static inline struct io_wq_acct *io_wq_get_acct(struct io_worker *worker)
return io_get_acct(worker->wq, worker->flags & IO_WORKER_F_BOUND);
}
-static void io_worker_ref_put(struct io_wq *wq)
+static void io_worker_ref_get(struct io_wq *wq, bool fixed)
+{
+ atomic_inc(&wq->worker_refs);
+ if (fixed)
+ atomic_inc(&wq->fixed_worker_refs);
+}
+
+static void io_worker_ref_put(struct io_wq *wq, bool fixed)
{
if (atomic_dec_and_test(&wq->worker_refs))
complete(&wq->worker_done);
+
+ if (fixed && atomic_dec_and_test(&wq->fixed_worker_refs))
+ complete(&wq->fixed_worker_done);
+}
+
+static bool is_fixed_worker(struct io_worker *worker)
+{
+ return worker->flags & IO_WORKER_F_FIXED;
}
static void io_worker_cancel_cb(struct io_worker *worker)
@@ -187,7 +206,7 @@ static void io_worker_cancel_cb(struct io_worker *worker)
raw_spin_lock(&wq->lock);
acct->nr_workers--;
raw_spin_unlock(&wq->lock);
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, is_fixed_worker(worker));
clear_bit_unlock(0, &worker->create_state);
io_worker_release(worker);
}
@@ -205,6 +224,7 @@ static bool io_task_worker_match(struct callback_head *cb, void *data)
static void io_worker_exit(struct io_worker *worker)
{
struct io_wq *wq = worker->wq;
+ bool fixed = is_fixed_worker(worker);
while (1) {
struct callback_head *cb = task_work_cancel_match(wq->task,
@@ -230,7 +250,7 @@ static void io_worker_exit(struct io_worker *worker)
preempt_enable();
kfree_rcu(worker, rcu);
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, fixed);
do_exit(0);
}
@@ -302,7 +322,7 @@ static struct io_worker *io_wq_create_worker(struct io_wq *wq,
acct->nr_workers++;
raw_spin_unlock(&wq->lock);
atomic_inc(&acct->nr_running);
- atomic_inc(&wq->worker_refs);
+ io_worker_ref_get(wq, fixed);
return create_io_worker(wq, acct->index, fixed);
}
@@ -313,11 +333,6 @@ static void io_wq_inc_running(struct io_worker *worker)
atomic_inc(&acct->nr_running);
}
-static bool is_fixed_worker(struct io_worker *worker)
-{
- return worker->flags & IO_WORKER_F_FIXED;
-}
-
static void create_worker_cb(struct callback_head *cb)
{
struct io_worker *worker;
@@ -325,8 +340,10 @@ static void create_worker_cb(struct callback_head *cb)
struct io_wq_acct *acct;
bool do_create = false;
+ bool fixed;
worker = container_of(cb, struct io_worker, create_work);
+ fixed = is_fixed_worker(worker);
wq = worker->wq;
acct = &wq->acct[worker->create_index];
raw_spin_lock(&wq->lock);
@@ -337,10 +354,10 @@ static void create_worker_cb(struct callback_head *cb)
}
raw_spin_unlock(&wq->lock);
if (do_create) {
- create_io_worker(wq, worker->create_index, is_fixed_worker(worker));
+ create_io_worker(wq, worker->create_index, fixed);
} else {
atomic_dec(&acct->nr_running);
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, fixed);
}
clear_bit_unlock(0, &worker->create_state);
io_worker_release(worker);
@@ -351,6 +368,7 @@ static bool io_queue_worker_create(struct io_worker *worker,
task_work_func_t func)
{
struct io_wq *wq = worker->wq;
+ bool fixed = is_fixed_worker(worker);
/* raced with exit, just ignore create call */
if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
@@ -367,7 +385,7 @@ static bool io_queue_worker_create(struct io_worker *worker,
test_and_set_bit_lock(0, &worker->create_state))
goto fail_release;
- atomic_inc(&wq->worker_refs);
+ io_worker_ref_get(wq, fixed);
init_task_work(&worker->create_work, func);
worker->create_index = acct->index;
if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) {
@@ -379,16 +397,16 @@ static bool io_queue_worker_create(struct io_worker *worker,
*/
if (test_bit(IO_WQ_BIT_EXIT, &wq->state))
io_wq_cancel_tw_create(wq);
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, fixed);
return true;
}
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, fixed);
clear_bit_unlock(0, &worker->create_state);
fail_release:
io_worker_release(worker);
fail:
atomic_dec(&acct->nr_running);
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, fixed);
return false;
}
@@ -408,7 +426,7 @@ static void io_wq_dec_running(struct io_worker *worker)
return;
atomic_inc(&acct->nr_running);
- atomic_inc(&wq->worker_refs);
+ io_worker_ref_get(wq, false);
io_queue_worker_create(worker, acct, create_worker_cb);
}
@@ -790,7 +808,7 @@ static void create_worker_cont(struct callback_head *cb)
} else {
raw_spin_unlock(&wq->lock);
}
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, is_fixed_worker(worker));
kfree(worker);
return;
}
@@ -824,7 +842,7 @@ static struct io_worker *create_io_worker(struct io_wq *wq, int index, bool fixe
raw_spin_lock(&wq->lock);
acct->nr_workers--;
raw_spin_unlock(&wq->lock);
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, fixed);
return tsk ? (struct io_worker *)tsk : ERR_PTR(-ENOMEM);
}
@@ -1243,7 +1261,7 @@ static void io_wq_exit_workers(struct io_wq *wq)
rcu_read_lock();
io_wq_for_each_worker(wq, io_wq_worker_wake, NULL);
rcu_read_unlock();
- io_worker_ref_put(wq);
+ io_worker_ref_put(wq, false);
wait_for_completion(&wq->worker_done);
spin_lock_irq(&wq->hash->wait.lock);
@@ -1390,6 +1408,7 @@ static void io_wq_clean_fixed_workers(struct io_wq *wq)
}
kfree(workers);
}
+ wait_for_completion(&wq->fixed_worker_done);
}
/*
@@ -1421,6 +1440,13 @@ int io_wq_fixed_workers(struct io_wq *wq, struct io_uring_fixed_worker_arg *coun
rcu_read_lock();
+ atomic_set(&wq->fixed_worker_refs, 1);
+ if (wq->fixed_comp_init) {
+ reinit_completion(&wq->fixed_worker_done);
+ } else {
+ init_completion(&wq->fixed_worker_done);
+ wq->fixed_comp_init = true;
+ }
for (i = 0; i < IO_WQ_ACCT_NR; i++) {
unsigned int nr = count[i].nr_workers;
@@ -1495,12 +1521,18 @@ int io_wq_destroy_fixed_workers(struct io_wq *wq)
workers[j]->flags |= IO_WORKER_F_EXIT;
wake_up_process(worker->task);
}
- // wait for all workers exit
kfree(workers);
}
raw_spin_unlock(&wq->lock);
rcu_read_unlock();
+ // decrement the init reference
+ if (atomic_dec_and_test(&wq->fixed_worker_refs))
+ complete(&wq->fixed_worker_done);
+
+ wait_for_completion(&wq->fixed_worker_done);
+ wq->fixed_comp_init = false;
+
return 0;
}
--
2.25.1
