On Tue, Sep 05, 2017 at 09:19:30AM +0200, Peter Zijlstra wrote: > On Tue, Sep 05, 2017 at 09:08:25AM +0200, Peter Zijlstra wrote: > > So you worry about max_active==1 ? Or you worry about pool->lock or > > about the thread setup? I'm still not sure. > > So the thing about pool->lock is that its a leaf lock, we take nothing
I think the following sentence is a key, I hope... Leaf locks can also create dependecies with *crosslocks*. These dependencies are not built between holding locks like typical locks. > inside it. Futhermore its a spinlock and therefore blocking things like > completions or page-lock cannot form a deadlock with it. I agree. Now we should be only interested in blocking things. > It is also fully isolated inside workqueue.c and easy to audit. > > This is why I really can't be arsed about it. > > And the whole setup stuff isn't properly preserved between works in any > case, only the first few works would ever see that history, so why > bother. As I said in another reply, what about (1), (3) and (5) in my example?
