On Thu, Oct 12, 2017 at 6:51 AM, Jan Kara <jack@xxxxxxx> wrote: > > When thinking a bit more about this I've realized one problem: Currently > user can call mmap() with MAP_SHARED type and MAP_SYNC or MAP_DIRECT flags > and he will get the new semantics (if the kernel happens to support it). I > think that is undesirable [..] Why? If you have a performance preference for MAP_DIRECT or something like that, but you don't want to *enforce* it, you'd use just plain MAP_SHARED with it. Ie there may well be "I want this to work, possibly with downsides" issues. So it seems to be a reasonable model, and disallowing it seems to limit people and not really help anything. Linus -- 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>