On Tue, Feb 20, 2018 at 03:34:07PM +0100, Christian König wrote: > > OK, but neither case would in fact need the !ctx case right? That's just > > there for completeness sake? > > Unfortunately not. TTM uses trylock to lock BOs which are about to be > evicted to make room for all the BOs locked with a ctx. > > I need to be able to distinct between the BOs which are trylocked and those > which are locked with a ctx. > > Writing this I actually noticed the current version is buggy, cause even > when we check the mutex owner we still need to make sure that the ctx in the > lock is NULL. Hurm... I can't remember why trylocks behave like that, and it seems rather unfortunate / inconsistent. Chris, Maarten, do either one of you remember? I'm thinking that if we do acquire the trylock, the thing should join the ctx such that a subsequent contending mutex_lock() can ww right.
