On Mon, Dec 22, 2014 at 03:51:24PM -0800, Davidlohr Bueso wrote: > Hello, > > I would like to attend LSF/MM 2015. While I am very much interested in > general mm performance topics, I would particularly like to discuss: > > (1) Where we are at with the mmap_sem issues and progress. This topic > constantly comes up each year [1,2,3] without much changing. While the > issues are very clear (both long hold times, specially in fs paths and > coarse lock granularity) it would be good to detail exactly *where* > these problems are and what are some of the show stoppers. In addition, > present overall progress and benchmark numbers on fine graining via > range locking (I am currently working on this as a follow on to recent > i_mmap locking patches) and experimental work, > such as speculative page fault patches[4]. If nothing else, this session > can/should produce a list of tangible todo items. > There have been changes on mmap_sem hold times -- mmap_sem dropped by khugepaged during allocation being a very obvious one but there are others. The scope of what mmap_sem protects is similar but the stalling behaviour has changed since this was last discussed. It's worth revisiting where things stand and at the very least verify what cases are currently causing problems. -- Mel Gorman SUSE Labs -- 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>