在 2021/9/13 上午2:10, Jens Axboe 写道:
On 9/11/21 1:40 PM, Hao Xu wrote:
The return value of io_wqe_create_worker() should be false if we cannot
create a new worker according to the name of this function.
Signed-off-by: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx>
---
fs/io-wq.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 382efca4812b..1b102494e970 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -267,7 +267,7 @@ static bool io_wqe_create_worker(struct io_wqe *wqe, struct io_wqe_acct *acct)
return create_io_worker(wqe->wq, wqe, acct->index);
}
- return true;
+ return false;
}
I think this is just a bit confusing. It's not an error case, we just
didn't need to create a worker. So don't return failure, or the caller
will think that we failed while we did not.
hmm, I think it is an error case----'we failed to create a new worker
since nr_worker == max_worker'. nr_worker == max_worker doesn't mean
'no need', we may meet situation describled in 4/4: max_worker is 1,
currently 1 worker is running, and we return true here:
did_create = io_wqe_create_worker(wqe, acct);
//*******nr_workers changes******//
if (unlikely(!did_create)) {
raw_spin_lock(&wqe->lock);
/* fatal condition, failed to create the first worker */
if (!acct->nr_workers) {
raw_spin_unlock(&wqe->lock);
goto run_cancel;
}
raw_spin_unlock(&wqe->lock);
}
we will miss the next check, but we have to do the check, since
number of workers may decrease to 0 in //******// place.
or maybe we can see the return value as 'do we create a new worker or
not', and the next code do safe check if it is false.
