在 2021/8/9 下午10:01, Jens Axboe 写道:
On 8/8/21 7:54 AM, Hao Xu wrote:The former patch to add check between nr_workers and max_workers has a bug, which will cause unconditionally creating io-workers. That's because the result of the check doesn't affect the call of create_io_worker(), fix it by bringing in a boolean value for it. Fixes: 21698274da5b ("io-wq: fix lack of acct->nr_workers < acct->max_workers judgement") Signed-off-by: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx> --- fs/io-wq.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/fs/io-wq.c b/fs/io-wq.c index 12fc19353bb0..5536b2a008d1 100644 --- a/fs/io-wq.c +++ b/fs/io-wq.c @@ -252,14 +252,15 @@ static void io_wqe_wake_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)raw_spin_lock_irq(&wqe->lock);if (acct->nr_workers < acct->max_workers) { - atomic_inc(&acct->nr_running); - atomic_inc(&wqe->wq->worker_refs); acct->nr_workers++; do_create = true; } raw_spin_unlock_irq(&wqe->lock); - if (do_create) + if (do_create) { + atomic_inc(&acct->nr_running); + atomic_inc(&wqe->wq->worker_refs); create_io_worker(wqe->wq, wqe, acct->index); + } }I don't get this hunk - we already know we're creating a worker, what's the point in moving the incs?
Actually not much difference, I think we don't need to protect nr_running and worker_refs by wqe->lock, so narrow the range of raw_spin_lock_irq - raw_spin_unlock_irq
