Re: [PATCH] fs: optimise kiocb_set_rw_flags()

[Matthew Wilcox]

On Sat, Aug 01, 2020 at 01:36:33PM +0300, Pavel Begunkov wrote:
> Use a local var to collect flags in kiocb_set_rw_flags(). That spares
> some memory writes and allows to replace most of the jumps with MOVEcc.
> 
> Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>

Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>

If you want to improve the codegen here further, I would suggest that
renumbering the IOCB flags to match the RWF flags would lead to better
codegen (can't do it the other way around; RWF flags are userspace ABI,
IOCB flags are not).  iocb_flags() probably doesn't get any worse because
the IOCB_ flags don't have the same numbers as the O_ bits (which differ
by arch anyway).