On Fri, Apr 28, 2017 at 03:33:07PM -0400, Jerome Glisse wrote: > On Fri, Apr 28, 2017 at 12:22:24PM -0700, Dan Williams wrote: > > Are you sure about needing to hook the 2 -> 1 transition? Could we > > change ZONE_DEVICE pages to not have an elevated reference count when > > they are created so you can keep the HMM references out of the mm hot > > path? > > 100% sure on that :) I need to callback into driver for 2->1 transition > no way around that. If we change ZONE_DEVICE to not have an elevated > reference count that you need to make a lot more change to mm so that > ZONE_DEVICE is never use as fallback for memory allocation. Also need > to make change to be sure that ZONE_DEVICE page never endup in one of > the path that try to put them back on lru. There is a lot of place that > would need to be updated and it would be highly intrusive and add a > lot of special cases to other hot code path. Could you explain more on where the requirement comes from or point me to where I can read about this. -- Kirill A. Shutemov -- 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>
