verbs: Add new unordered MR access flag - #1780
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To commit: 3fbf618b8897 ("RDMA/uverbs: Add new Unordered MR access flag").
Signed-off-by: Michael Gur <michaelgur@nvidia.com>
Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Fix typos and grammar. Signed-off-by: Michael Gur <michaelgur@nvidia.com> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Add a new Unordered access flag for MR registrations. This access flag allows additional relaxing of the order of memory accesses to the memory region. Using this access flag allows for concurrent reads and writes of this MR to be reordered. This access flag is part of the optional access flags range, drivers shouldn't fail registration for any value in this range and are expected to treat them as best-effort. The new access flag is defined as a mask of the new unordered bit and the existing relaxed bit. This guarantees backward compatibility: applications opting into unordered access will still benefit from relaxed ordering on older kernels that don't handle the new bit. Update the man page to document both ordering access flags under a new ORDERING SEMANTICS section. Signed-off-by: Michael Gur <michaelgur@nvidia.com> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Add unordered access option to all five pingpong example applications. Relaxing access to data is recommended for performance reasons for all RDMA applications that don't poll data and rely on completions for their memory access logic. Additionally, without this flag the examples will fail to register memory on HW that restricts strong-ordered memory registration. Signed-off-by: Michael Gur <michaelgur@nvidia.com> Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
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This series introduces a new optional MR access flag named IBV_ACCESS_UNORDERED.
This access flag allows additional relaxing of the order of memory accesses to the memory region.
Using this access flag allows for concurrent reads and writes of this MR to be reordered.
Extra details exist as part of the man page and along the commit messages in the series.
The matching kernel part was sent already to rdma-next.