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Code Issues Releases Wiki Activity

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

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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: 2e480058dd ("io-wq: provide a way to limit max number of workers")
Signed-off-by: Beld Zhang <beldzhang@gmail.com>
[axboe: minor fixups]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Beld Zhang 2021-11-02 12:32:08 -06:00 committed by Jens Axboe
parent 9881024aab
commit 71c9ce27bb
1 changed files with 13 additions and 3 deletions
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16
fs/io-wq.c
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@ -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;
}