On Fri, Apr 28, 2017 at 10:34 AM, Jerome Glisse <jglisse@xxxxxxxxxx> wrote: >> Kirill points out that the calls to {get,put}_dev_pagemap() can be >> removed from the mm fast path if we take a single get_dev_pagemap() >> reference to signify that the page is alive and use the final put of the >> page to drop that reference. >> >> This does require some care to make sure that any waits for the >> percpu_ref to drop to zero occur *after* devm_memremap_page_release(), >> since it now maintains its own elevated reference. > > This is NAK from HMM point of view as i need those call. So if you remove > them now i will need to add them back as part of HMM. I thought you only need them at page free time? You can still hook __put_page(). -- 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>