io_uring/io-wq: inherit cpuset of cgroup in io worker

The io worker threads are userland threads that just never exit to the
userland. By that, they are also assigned to a cgroup (the group of the
creating task).

When creating a new io worker, this worker should inherit the cpuset
of the cgroup.

Fixes: da64d6d ("io_uring: One wqe per wq")
Signed-off-by: Felix Moessbauer <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jens Axboe <[email protected]>

Author: fmoessbauer

io_uring/io-wq.c

@@ -1168,7 +1168,7 @@ struct io_wq *io_wq_create(unsigned bounded, struct io_wq_data *data)
 
 	if (!alloc_cpumask_var(&wq->cpu_mask, GFP_KERNEL))
 		goto err;
-	cpumask_copy(wq->cpu_mask, cpu_possible_mask);
+	cpuset_cpus_allowed(data->task, wq->cpu_mask);
 	wq->acct[IO_WQ_ACCT_BOUND].max_workers = bounded;
 	wq->acct[IO_WQ_ACCT_UNBOUND].max_workers =
 				task_rlimit(current, RLIMIT_NPROC);