On Tue 02-05-17 08:18:15, Christoph Hellwig wrote: > On Tue, May 02, 2017 at 05:15:58PM +0200, Jan Kara wrote: > > in generic_make_request_checks()? Or just set it unconditionally in that > > function if we see REQ_FUA | REQ_PREFLUSH set? > > Just add REQ_FUA and REQ_PREFLUSH to the test in op_is_sync. It is there. The problem happens when REQ_FUA and REQ_PREFLUSH get stripped from bio because the underlying storage doesn't have volatile cache, the bio suddently becomes treated as async which regresses performance. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
