Re: [PATCH for-next] RDMA/hns: Add interface to support lock free

[Leon Romanovsky <leon@kernel.org>]

On Thu, Mar 12, 2020 at 01:04:05PM -0400, Andrew Boyer wrote:
> What would you say to a per-process env variable to disable locking in a userspace provider?

We have thread-domain concept in libibverbs to achieve lockless flows.
https://github.com/linux-rdma/rdma-core/blob/master/libibverbs/man/ibv_alloc_td.3

BTW, please don't use top-posting.

Thanks

>
> -Andrew
>
> > On Mar 12, 2020, at 1:02 PM, Jason Gunthorpe <jgg@ziepe.ca> wrote:
> >
> > On Thu, Mar 12, 2020 at 11:26:40AM +0200, Leon Romanovsky wrote:
> >> On Thu, Mar 12, 2020 at 03:48:10PM +0800, Weihang Li wrote:
> >>> From: Jiaran Zhang <zhangjiaran@huawei.com>
> >>>
> >>> In some scenarios, ULP can ensure that there is no concurrency when
> >>> processing io, thus lock free can be used to improve performance.
> >>>
> >>> Signed-off-by: Jiaran Zhang <zhangjiaran@huawei.com>
> >>> Signed-off-by: Yixian Liu <liuyixian@huawei.com>
> >>> Signed-off-by: Weihang Li <liweihang@huawei.com>
> >>> drivers/infiniband/hw/hns/hns_roce_device.h |   1 +
> >>> drivers/infiniband/hw/hns/hns_roce_hw_v2.c  | 112 ++++++++++++++++++++--------
> >>> drivers/infiniband/hw/hns/hns_roce_qp.c     |   1 +
> >>> 3 files changed, 84 insertions(+), 30 deletions(-)
> >>>
> >>
> >> NAK, everything in this patch is wrong, starting from exposure,
> >> implementation and description.
> >
> > Yes, complete no on a module parameter to disable locking.
> >
> > Jason
>