On Tue, May 08, 2018 at 10:42:01AM -0700, adam.manzanares@xxxxxxx wrote: > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 760d8da1b6c7..7a90ce387e00 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -284,6 +284,8 @@ enum rw_hint { > WRITE_LIFE_EXTREME = RWH_WRITE_LIFE_EXTREME, > }; > > +#define MAX_KI_HINT ((1 << 16) - 1) /* ki_hint type is u16 */ > + Do we really think there will be *ever* be a need for more than 16 I/O priority levels? I would much rather use the low four bits of KI_HINT for the priority level, and reserve the rest of the 16 bits in KI_HINT for some future use. (For example, we might want to use some number of bits for a stream ID.) - Ted