io-wq: check max_worker limits if a worker transitions bound state
For the two places where new workers are created, we diligently check if we are allowed to create a new worker. If we're currently at the limit of how many workers of a given type we can have, then we don't create any new ones. If you have a mixed workload with various types of bound and unbounded work, then it can happen that a worker finishes one type of work and is then transitioned to the other type. For this case, we don't check if we are actually allowed to do so. This can cause io-wq to temporarily exceed the allowed number of workers for a given type. When retrieving work, check that the types match. If they don't, check if we are allowed to transition to the other type. If not, then don't handle the new work. Cc: stable@vger.kernel.org Reported-by:Johannes Lundberg <johalun0@gmail.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk>
parent
f1042b6c
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