On 06/15/2017 02:17 AM, Christoph Hellwig wrote: > On Wed, Jun 14, 2017 at 09:45:04PM -0600, Jens Axboe wrote: >> No functional changes in this patch, just in preparation for >> allowing applications to pass in hints about data life times >> for writes. >> >> Pack the i_write_hint field into a 2-byte hole, so we don't grow >> the size of the inode. > > A u8 should be plenty. But talking about the representation - > your write lifetime hints are a 5 option enum basically. I wonder > if we really should encode it as flags, or if we should have an > enum (which could be packed into a 3-bit bitfield) and then pass > it down the stack in that form instead of changing the representation > N times. If we keep the RWF_WRITE_LIFE_* flags, then yes, I think we should unify the RWF_WRITE_LIFE_*, IOCB_WRITE_LIFE_*, and REQ_WRITE_LIFE_* flags into a specific type. -- Jens Axboe
