On Wed, Jul 24, 2019 at 08:51:46AM +0200, Christoph Hellwig wrote: > On Tue, Jul 23, 2019 at 04:30:16PM -0700, Ralph Campbell wrote: > > hmm_range_snapshot() and hmm_range_fault() both call find_vma() and > > walk_page_range() in a loop. This is unnecessary duplication since > > walk_page_range() calls find_vma() in a loop already. > > Simplify hmm_range_snapshot() and hmm_range_fault() by defining a > > walk_test() callback function to filter unhandled vmas. > > I like the approach a lot! > > But we really need to sort out the duplication between hmm_range_fault > and hmm_range_snapshot first, as they are basically the same code. I > have patches here: > > http://git.infradead.org/users/hch/misc.git/commitdiff/a34ccd30ee8a8a3111d9e91711c12901ed7dea74 > > http://git.infradead.org/users/hch/misc.git/commitdiff/81f442ebac7170815af7770a1efa9c4ab662137e Yeah, that is a straightforward improvement, maybe Ralph should grab these two as part of his series? > That being said we don't really have any users for the snapshot mode > or non-blocking faults, and I don't see any in the immediate pipeline > either. If this code was production ready I'd use it in ODP right away. When we first create a ODP MR we'd want to snapshot to pre-load the NIC tables with something other than page fault, but not fault anything. This would be a big performance improvement for ODP. Jason
