Quoting Michal Hocko (2017-08-21 15:06:42) > On Sat 19-08-17 14:15:35, Chris Wilson wrote: > > Quoting Michal Hocko (2017-06-06 13:14:18) > > > On Tue 06-06-17 13:04:36, Chris Wilson wrote: > > > > Similar in principle to the treatment of get_user_pages, pages that > > > > i915.ko acquires from shmemfs are not immediately reclaimable and so > > > > should be excluded from the mm accounting and vmscan until they have > > > > been returned to the system via shrink_slab/i915_gem_shrink. By moving > > > > the unreclaimable pages off the inactive anon lru, not only should > > > > vmscan be improved by avoiding walking unreclaimable pages, but the > > > > system should also have a better idea of how much memory it can reclaim > > > > at that moment in time. > > > > > > That is certainly desirable. Peter has proposed a generic pin_page (or > > > similar) API. What happened with it? I think it would be a better > > > approach than (ab)using mlock API. I am also not familiar with the i915 > > > code to be sure that using lock_page is really safe here. I think that > > > all we need is to simply move those pages in/out to/from unevictable LRU > > > list on pin/unpining. > > > > I just had the opportunity to try this mlock_vma_page() hack on a > > borderline swapping system (i.e. lots of vmpressure between i915 buffers > > and the buffercache), and marking the i915 pages as unevictable makes a > > huge difference in avoiding stalls in direct reclaim across the system. > > > > Reading back over the thread, it seems that the simplest approach going > > forward is a small api for managing the pages on the unevictable LRU? > > Yes and I thought that pin_page API would do exactly that. My googlefu says "[RFC][PATCH 1/5] mm: Introduce VM_PINNED and interfaces" is the series, and it certainly targets the very same problem. Peter, is that the latest version? -Chris -- 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
