On Wed, May 21, 2014 at 02:26:22PM -0700, Andrew Morton wrote: > > +static inline void > > +__prepare_to_wait(wait_queue_head_t *q, wait_queue_t *wait, > > + struct page *page, int state, bool exclusive) > > Putting MM stuff into core waitqueue code is rather bad. I really > don't know how I'm going to explain this to my family. Right, so we could avoid all that and make the functions in mm/filemap.c rather large and opencode a bunch of wait.c stuff. Which is pretty much what I initially pseudo proposed. > > + __ClearPageWaiters(page); > > We're freeing the page - if someone is still waiting on it then we have > a huge bug? It's the mysterious collision thing again I hope? Yeah, so we only clear that bit when at 'unlock' we find there are no more pending waiters, so if the last unlock still had a waiter, we'll leave the bit set. So its entirely reasonable to still have it set when we free a page etc.. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>