From: Rusty Russell <rusty@rustcorp.com.au>
To: Alexander Duyck <alexander.h.duyck@redhat.com>,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org
Cc: mst@redhat.com
Subject: Re: [PATCH] virtio_ring: Update weak barriers to use dma_wmb/rmb
In-Reply-To: <20150408004742.2112.25484.stgit@ahduyck-vm-fedora22>
References: <20150408004742.2112.25484.stgit@ahduyck-vm-fedora22>
User-Agent: Notmuch/0.17 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu)
Date: Fri, 10 Apr 2015 12:47:01 +0930
Message-ID: <871tjs1xle.fsf@rustcorp.com.au>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 927
Lines: 24

Alexander Duyck <alexander.h.duyck@redhat.com> writes:
> This change makes it so that instead of using smp_wmb/rmb which varies
> depending on the kernel configuration we can can use dma_wmb/rmb which for
> most architectures should be equal to or slightly more strict than
> smp_wmb/rmb.
>
> The advantage to this is that these barriers are available to uniprocessor
> builds as well so the performance should improve under such a
> configuration.
>
> Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>

This seems OK to me, since it's really as much a cleanup as anything,
but like you I do wonder if there benefit on ARM in practice.

Applied, thanks.

Cheers,
Rusty.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/