On 6/9/23 13:20, Hao Xu wrote:
From: Hao Xu <howeyxu@xxxxxxxxxxx>
Add a new parameter when creating new workers to indicate if users
want a normal or fixed worker.
Signed-off-by: Hao Xu <howeyxu@xxxxxxxxxxx>
---
io_uring/io-wq.c | 33 ++++++++++++++++++++-------------
1 file changed, 20 insertions(+), 13 deletions(-)
diff --git a/io_uring/io-wq.c b/io_uring/io-wq.c
index bf9e9af8d9ca..048856eef4d4 100644
--- a/io_uring/io-wq.c
+++ b/io_uring/io-wq.c
[...]
+static bool is_fixed_worker(struct io_worker *worker)
+{
+ return worker->flags & IO_WORKER_F_FIXED;
+}
That's what I mentioned in the other comment.
+
static void create_worker_cb(struct callback_head *cb)
{
struct io_worker *worker;
@@ -331,7 +337,7 @@ static void create_worker_cb(struct callback_head *cb)
}
raw_spin_unlock(&wq->lock);
if (do_create) {
- create_io_worker(wq, worker->create_index);
+ create_io_worker(wq, worker->create_index, is_fixed_worker(worker));
} else {
atomic_dec(&acct->nr_running);
io_worker_ref_put(wq);
@@ -398,6 +404,8 @@ static void io_wq_dec_running(struct io_worker *worker)
return;
if (!io_acct_run_queue(acct))
return;
+ if (is_fixed_worker(worker))
+ return;
Aha, it's here. I was thinking about it a little bit more.
Is it even correct? If you have a mixed fixed/non-fixed setup
you presumably want non-fixed workers to kick in such situations.
I don't remember this creation voodoo well, maybe Jens does have
an idea.
atomic_inc(&acct->nr_running);
atomic_inc(&wq->worker_refs);
@@ -601,11 +609,6 @@ static bool is_worker_exiting(struct io_worker *worker)
return worker->flags & IO_WORKER_F_EXIT;
}
[...]
-static bool create_io_worker(struct io_wq *wq, int index)
+static bool create_io_worker(struct io_wq *wq, int index, bool fixed)
{
struct io_wq_acct *acct = &wq->acct[index];
struct io_worker *worker;
@@ -833,10 +836,14 @@ static bool create_io_worker(struct io_wq *wq, int index)
if (index == IO_WQ_ACCT_BOUND)
worker->flags |= IO_WORKER_F_BOUND;
+ if (fixed)
+ worker->flags |= IO_WORKER_F_FIXED;
+
tsk = create_io_thread(io_wq_worker, worker, NUMA_NO_NODE);
if (!IS_ERR(tsk)) {
- io_init_new_worker(wq, worker, tsk);
- } else if (!io_should_retry_thread(PTR_ERR(tsk))) {
+ if (!fixed)
+ io_init_new_worker(wq, worker, tsk);
Why do we skip io_init_new_worker()? I assume you putting it
into lists, but what about the rest? I.e.
tsk->worker_private = worker;
worker->task = tsk;
set_cpus_allowed_ptr(tsk, wq->cpu_mask);
+ } else if (fixed || !io_should_retry_thread(PTR_ERR(tsk))) {
kfree(worker);
goto fail;
} else {
@@ -947,7 +954,7 @@ void io_wq_enqueue(struct io_wq *wq, struct io_wq_work *work)
!atomic_read(&acct->nr_running))) {
bool did_create;
- did_create = io_wq_create_worker(wq, acct);
+ did_create = io_wq_create_worker(wq, acct, false);
if (likely(did_create))
return;
--
Pavel Begunkov
