netdev - Re: [PATCH v8 0/7] netdev: intel: Eliminate duplicate barriers on weakly-ordered archs

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Message-ID: <1522779967.4236.22.camel@intel.com>
Date:   Tue, 03 Apr 2018 11:26:07 -0700
From:   Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To:     Sinan Kaya <okaya@...eaurora.org>,
        Alexander Duyck <alexander.duyck@...il.com>,
        intel-wired-lan <intel-wired-lan@...ts.osuosl.org>
Cc:     Netdev <netdev@...r.kernel.org>, Timur Tabi <timur@...eaurora.org>,
        sulrich@...eaurora.org, linux-arm-msm@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v8 0/7] netdev: intel: Eliminate duplicate barriers on
 weakly-ordered archs

On Tue, 2018-04-03 at 13:50 -0400, Sinan Kaya wrote:
> > > What do you think about this version? Did I miss any SMP
> > > barriers?
> > 
> > I would say we should probably just drop the whole set and start
> > over.
> > If we don't need the wmb() we are going to need to go through and
> > clean up all of these paths and consider the barriers when updating
> > the layout of the code.
> > 
> > For example I have been thinking about it and in the case of x86 we
> > are probably better off not bothering with the wmb() and
> > writel_relaxed() and instead switch over to the smp_wmb() and
> > writel()
> > since in the case of a strongly ordered system like x86 or sparc
> > this
> > ends up translating out to a couple of compile barriers.
> > 
> > I will also need time to reevaluate the Rx paths since dropping the
> > wmb() may have other effects which I need to verify.
> 
> Sounds good, I'll let you work on it.
> 
> @Jeff Kirsher: can you drop this version from your development branch
> until
> Alex posts the next version?

Already on it, I will work with Alex on any possible future versions of
these patches.
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