On Tue, 2014-01-28 at 19:36 -0500, Naoya Horiguchi wrote: > On Mon, Jan 27, 2014 at 06:34:17PM -0800, Davidlohr Bueso wrote: [...] > > > If this retry is really essential for the fix, please comment the reason > > > both in patch description and inline comment. It's very important for > > > future code maintenance. > > > > So we locate the corresponding region in the reserve map, and if we are > > below the current region, then we allocate a new one. Since we dropped > > the lock to allocate memory, we have to make sure that we still need the > > new region and that we don't race with the new status of the reservation > > map. This is the whole point of the retry, and I don't see it being > > suboptimal. > > I'm afraid that you don't explain why you need drop the lock for memory > allocation. Are you saying that this unlocking comes from the difference > between rwsem and spin lock? Because you cannot go to sleep while holding a spinlock, which is exactly what kmalloc(GFP_KERNEL) can do. We *might* get a way with it with GFP_ATOMIC, I dunno, but I certainly prefer this approach better. Thanks, Davidlohr -- 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>