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From: John Fastabend <john.fastabend@gmail.com>
To: "Björn Töpel" <bjorn.topel@gmail.com>,
	netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net
Cc: "Björn Töpel" <bjorn.topel@intel.com>,
	bpf@vger.kernel.org, magnus.karlsson@intel.com,
	jonathan.lemon@gmail.com
Subject: RE: [PATCH bpf-next] xsk: update rings for load-acquire/store-release semantics
Date: Mon, 20 Jan 2020 17:24:52 -0800	[thread overview]
Message-ID: <5e2652e4239a8_20912afc5c86e5c49f@john-XPS-13-9370.notmuch> (raw)
In-Reply-To: <20200120092149.13775-1-bjorn.topel@gmail.com>

Björn Töpel wrote:
> From: Björn Töpel <bjorn.topel@intel.com>
> 
> Currently, the AF_XDP rings uses fences for the kernel-side
> produce/consume functions. By updating rings for
> load-acquire/store-release semantics, the full barrier (smp_mb()) on
> the consumer side can be replaced.
> 
> Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
> ---
>  net/xdp/xsk_queue.h | 31 ++++++++++++++-----------------
>  1 file changed, 14 insertions(+), 17 deletions(-)
> 
> diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
> index bec2af11853a..2fff80576ee1 100644
> --- a/net/xdp/xsk_queue.h
> +++ b/net/xdp/xsk_queue.h
> @@ -39,19 +39,18 @@ struct xsk_queue {
>  	u64 invalid_descs;
>  };

Should the xsk_cons_* libbpf routines also be updated then as well?
In general my understanding is the userspace and kernel should be
in sync?

      parent reply	other threads:[~2020-01-21  1:25 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-20  9:21 [PATCH bpf-next] xsk: update rings for load-acquire/store-release semantics Björn Töpel
2020-01-20 23:27 ` Daniel Borkmann
2020-01-21 11:50   ` Björn Töpel
2020-03-16 18:44     ` Will Deacon
2020-03-17 19:14       ` Björn Töpel
2020-03-17 21:03         ` Will Deacon
2020-01-21  1:24 ` John Fastabend [this message]

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