Commit 71c9ce27 authored by Beld Zhang's avatar Beld Zhang Committed by Jens Axboe
Browse files

io-wq: fix max-workers not correctly set on multi-node system 



In io-wq.c:io_wq_max_workers(), new_count[] was changed right after each
node's value was set. This caused the following node getting the setting
of the previous one.

Returned values are copied from node 0.

Fixes: 2e480058 ("io-wq: provide a way to limit max number of workers")
Signed-off-by: default avatarBeld Zhang <beldzhang@gmail.com>
[axboe: minor fixups]
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 9881024a

fs/io-wq.c

+13 −3
Original line number Diff line number Diff line
@@ -1308,7 +1308,9 @@ int io_wq_cpu_affinity(struct io_wq *wq, cpumask_var_t mask) 
 */

int io_wq_max_workers(struct io_wq *wq, int *new_count)

{

	int i, node, prev = 0;

	int prev[IO_WQ_ACCT_NR];

	bool first_node = true;

	int i, node;



	BUILD_BUG_ON((int) IO_WQ_ACCT_BOUND   != (int) IO_WQ_BOUND);

	BUILD_BUG_ON((int) IO_WQ_ACCT_UNBOUND != (int) IO_WQ_UNBOUND);
@@ -1319,6 +1321,9 @@ int io_wq_max_workers(struct io_wq *wq, int *new_count) 
			new_count[i] = task_rlimit(current, RLIMIT_NPROC);

	}



	for (i = 0; i < IO_WQ_ACCT_NR; i++)

		prev[i] = 0;



	rcu_read_lock();

	for_each_node(node) {

		struct io_wqe *wqe = wq->wqes[node];
@@ -1327,14 +1332,19 @@ int io_wq_max_workers(struct io_wq *wq, int *new_count) 
		raw_spin_lock(&wqe->lock);

		for (i = 0; i < IO_WQ_ACCT_NR; i++) {

			acct = &wqe->acct[i];

			prev = max_t(int, acct->max_workers, prev);

			if (first_node)

				prev[i] = max_t(int, acct->max_workers, prev[i]);

			if (new_count[i])

				acct->max_workers = new_count[i];

			new_count[i] = prev;

		}

		raw_spin_unlock(&wqe->lock);

		first_node = false;

	}

	rcu_read_unlock();



	for (i = 0; i < IO_WQ_ACCT_NR; i++)

		new_count[i] = prev[i];



	return 0;

}