The io-wq threads were already marked as no-freeze, but the manager was
not. On resume, we perpetually have signal_pending() being true, and
hence the manager will loop and spin 100% of the time.
Just mark the tasks created by create_io_thread() as PF_NOFREEZE by
default, and remove any knowledge of it in io-wq and io_uring.
Reported-by: Kevin Locke <kevin@xxxxxxxxxxxxxxx>
Tested-by: Kevin Locke <kevin@xxxxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
fs/io-wq.c | 3 +--
fs/io_uring.c | 1 -
kernel/fork.c | 1 +
3 files changed, 2 insertions(+), 3 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 3d7060ba547a..0ae9ecadf295 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -591,7 +591,7 @@ static bool create_io_worker(struct io_wq *wq, struct io_wqe *wqe, int index)
tsk->pf_io_worker = worker;
worker->task = tsk;
set_cpus_allowed_ptr(tsk, cpumask_of_node(wqe->node));
- tsk->flags |= PF_NOFREEZE | PF_NO_SETAFFINITY;
+ tsk->flags |= PF_NO_SETAFFINITY;
raw_spin_lock_irq(&wqe->lock);
hlist_nulls_add_head_rcu(&worker->nulls_node, &wqe->free_list);
@@ -709,7 +709,6 @@ static int io_wq_manager(void *data)
set_current_state(TASK_INTERRUPTIBLE);
io_wq_check_workers(wq);
schedule_timeout(HZ);
- try_to_freeze();
if (fatal_signal_pending(current))
set_bit(IO_WQ_BIT_EXIT, &wq->state);
} while (!test_bit(IO_WQ_BIT_EXIT, &wq->state));
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 62f998bf2ce8..14165e18020c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6733,7 +6733,6 @@ static int io_sq_thread(void *data)
up_read(&sqd->rw_lock);
schedule();
- try_to_freeze();
down_read(&sqd->rw_lock);
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
io_ring_clear_wakeup_flag(ctx);
diff --git a/kernel/fork.c b/kernel/fork.c
index d3171e8e88e5..72e444cd0ffe 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2436,6 +2436,7 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
if (!IS_ERR(tsk)) {
sigfillset(&tsk->blocked);
sigdelsetmask(&tsk->blocked, sigmask(SIGKILL));
+ tsk->flags |= PF_NOFREEZE;
}
return tsk;
}
--
2.30.2
