On 2018/06/27 2:03, Paul E. McKenney wrote: > There are a lot of ways it could be made concurrency safe. If you need > me to do this, please do let me know. > > That said, the way it is now written, if you invoke rcu_oom_notify() > twice in a row, the second invocation will wait until the memory from > the first invocation is freed. What do you want me to do if you invoke > me concurrently? > > 1. One invocation "wins", waits for the earlier callbacks to > complete, then encourages any subsequent callbacks to be > processed more quickly. The other invocations return > immediately without doing anything. > > 2. The invocations serialize, with each invocation waiting for > the callbacks from previous invocation (in mutex_lock() order > or some such), and then starting a new round. > > 3. Something else? > > Thanx, Paul As far as I can see, - atomic_set(&oom_callback_count, 1); + atomic_inc(&oom_callback_count); should be sufficient.
