From: okaya@codeaurora.org
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: netdev@vger.kernel.org, timur@codeaurora.org,
sulrich@codeaurora.org, linux-arm-msm@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Michal Kalderon <Michal.Kalderon@cavium.com>,
Ariel Elior <Ariel.Elior@cavium.com>,
Doug Ledford <dledford@redhat.com>,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/7] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs
Date: Wed, 14 Mar 2018 08:06:32 -0400 [thread overview]
Message-ID: <c65f0d329aa50067a2c57ed71bba9131@codeaurora.org> (raw)
In-Reply-To: <20180314041249.GA18314@ziepe.ca>
On 2018-03-14 00:12, Jason Gunthorpe wrote:
> On Tue, Mar 13, 2018 at 11:20:24PM -0400, Sinan Kaya wrote:
>> Code includes wmb() followed by writel() in multiple places. writel()
>> already has a barrier on some architectures like arm64.
>>
>> This ends up CPU observing two barriers back to back before executing
>> the
>> register write.
>>
>> Since code already has an explicit barrier call, changing writel() to
>> writel_relaxed().
>>
>> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
>> drivers/infiniband/hw/qedr/verbs.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> Sure matches my understanding of writel_relaxed
>
> This is part of a series, should we take just this patch through the
> rdma tree? If not:
>
> Acked-by: Jason Gunthorpe <jgg@mellanox.com>
Feel free to take pieces.
>
> Thanks,
> Jason
next prev parent reply other threads:[~2018-03-14 12:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1520997629-17361-1-git-send-email-okaya@codeaurora.org>
2018-03-14 3:20 ` [PATCH 3/7] RDMA/qedr: eliminate duplicate barriers on weakly-ordered archs Sinan Kaya
2018-03-14 4:12 ` Jason Gunthorpe
2018-03-14 12:06 ` okaya [this message]
2018-03-15 22:23 ` Jason Gunthorpe
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