Re: [RFC PATCH 2/7] block: don't merge different kinds of P2P transfers in a single bio

[Leon Romanovsky <leon@kernel.org>]

On Sat, Nov 02, 2024 at 08:39:35AM +0100, Zhu Yanjun wrote:
> 在 2024/10/27 15:21, Leon Romanovsky 写道:
> > From: Christoph Hellwig <hch@lst.de>
> > 
> > To get out of the dma mapping helpers having to check every segment for
> > it's P2P status, ensure that bios either contain P2P transfers or non-P2P
> > transfers, and that a P2P bio only contains ranges from a single device.
> > 
> > This means we do the page zone access in the bio add path where it should
> > be still page hot, and will only have do the fairly expensive P2P topology
> > lookup once per bio down in the dma mapping path, and only for already
> > marked bios.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
> > ---
> >   block/bio.c               | 36 +++++++++++++++++++++++++++++-------
> >   block/blk-map.c           | 32 ++++++++++++++++++++++++--------
> >   include/linux/blk_types.h |  2 ++
> >   3 files changed, 55 insertions(+), 15 deletions(-)

<...>

> > @@ -410,6 +411,7 @@ enum req_flag_bits {
> >   #define REQ_DRV		(__force blk_opf_t)(1ULL << __REQ_DRV)
> >   #define REQ_FS_PRIVATE	(__force blk_opf_t)(1ULL << __REQ_FS_PRIVATE)
> >   #define REQ_ATOMIC	(__force blk_opf_t)(1ULL << __REQ_ATOMIC)
> > +#define REQ_P2PDMA	(__force blk_opf_t)(1ULL << __REQ_P2PDMA)
> 
> #define REQ_P2PDMA	(__force blk_opf_t)BIT_ULL(__REQ_P2PDMA)
> 
> Use BIT_ULL instead of direct left shit.

We keep coding style consistent and all defines above aren't implemented
with BIT_ULL().

Thanks

> 
> Zhu Yanjun
> 
> >   #define REQ_NOUNMAP	(__force blk_opf_t)(1ULL << __REQ_NOUNMAP)
>