From: Jason Gunthorpe <jgg@nvidia.com>
To: Tom Talpey <tom@talpey.com>
Cc: Xiao Yang <yangx.jy@fujitsu.com>,
linux-rdma@vger.kernel.org, yanjun.zhu@linux.dev,
rpearsonhpe@gmail.com, y-goto@fujitsu.com, lizhijian@fujitsu.com,
tomasz.gromadzki@intel.com
Subject: Re: [RFC PATCH 2/2] RDMA/rxe: Add RDMA Atomic Write operation
Date: Wed, 5 Jan 2022 19:53:54 -0400 [thread overview]
Message-ID: <20220105235354.GV2328285@nvidia.com> (raw)
In-Reply-To: <b5860ad7-5d5a-76ba-a18e-da90e8652b08@talpey.com>
On Thu, Dec 30, 2021 at 04:39:01PM -0500, Tom Talpey wrote:
> Because RXE is a software provider, I believe the most natural approach
> here is to use an atomic64_set(dst, *src).
A smp_store_release() is most likely sufficient.
The spec word 'atomic' is pretty confusing. What it is asking for, in
the modern memory model vernacular, is 'write once' for the entire
payload and 'release' to only be observable after other stores made by
the same QP.
'release' semantics will depend on the CPU complex having a release
dependency chain throughout all CPUs that completed any prior response
on the QP. It looks like this is achieved through tasklet scheduling..
Jason
next prev parent reply other threads:[~2022-01-05 23:55 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-30 12:14 [RFC PATCH 0/2] RDMA/rxe: Add RDMA Atomic Write operation Xiao Yang
2021-12-30 12:14 ` [RFC PATCH 1/2] RDMA/rxe: Rename send_atomic_ack() and atomic member of struct resp_res Xiao Yang
2021-12-30 12:14 ` [RFC PATCH 2/2] RDMA/rxe: Add RDMA Atomic Write operation Xiao Yang
2021-12-30 21:39 ` Tom Talpey
2021-12-31 8:29 ` yangx.jy
2021-12-31 15:09 ` Tom Talpey
[not found] ` <61D563B4.2070106@fujitsu.com>
2022-01-07 15:50 ` Tom Talpey
2022-01-07 17:11 ` Jason Gunthorpe
2022-01-12 9:24 ` yangx.jy
2022-01-05 23:53 ` Jason Gunthorpe [this message]
2022-01-06 10:52 ` yangx.jy
2022-01-06 13:00 ` Jason Gunthorpe
2022-01-07 2:15 ` yangx.jy
2022-01-07 12:22 ` Jason Gunthorpe
2022-01-07 15:38 ` Tom Talpey
2022-01-07 19:28 ` Jason Gunthorpe
2022-01-07 20:11 ` Tom Talpey
2021-12-31 3:01 ` lizhijian
2021-12-31 6:02 ` yangx.jy
2021-12-30 19:21 ` [RFC PATCH 0/2] " Gromadzki, Tomasz
2021-12-30 21:42 ` Tom Talpey
2021-12-31 6:30 ` yangx.jy
2022-01-04 9:28 ` yangx.jy
2022-01-04 15:17 ` Tom Talpey
2022-01-05 1:00 ` yangx.jy
2022-01-06 0:01 ` Jason Gunthorpe
2022-01-06 1:54 ` yangx.jy
2022-01-10 15:42 ` Jason Gunthorpe
2022-01-11 2:34 ` yangx.jy
2022-01-11 23:29 ` Jason Gunthorpe
2022-02-11 13:18 ` Gromadzki, Tomasz
2022-02-17 3:50 ` yangx.jy
2022-02-19 10:37 ` Leon Romanovsky
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