From: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
To: "J. Bruce Fields" <bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org>
Cc: Linux RDMA Mailing List
<linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Linux NFS Mailing List
<linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Fwd: [PATCH] svcrdma: Do not send XDR roundup bytes for a write chunk
Date: Thu, 12 Nov 2015 09:47:13 -0500 [thread overview]
Message-ID: <648A8847-9836-42EC-9D62-77C01C6E9ACF@oracle.com> (raw)
In-Reply-To: 20151112144433.13507.34603.stgit@klimt.1015granger.net
I wish git send-mail had an address book. I’m really tired
of misspelling the to/cc addresses on patches.
Resending so there is one thread for all replies. Apologies
for the noise.
> Begin forwarded message:
>
> From: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> Subject: [PATCH] svcrdma: Do not send XDR roundup bytes for a write chunk
> Date: November 12, 2015 at 9:44:33 AM EST
> To: bfields-uC3wQj2KruNg9hUCZPvPmw@public.gmane.org
> Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rmda-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>
> Minor optimization: when dealing with write chunk XDR roundup, do
> not post a Write WR for the zero bytes in the pad. Simply update
> the write segment in the RPC-over-RDMA header to reflect the extra
> pad bytes.
>
> The Reply chunk is also a write chunk, but the server does not use
> send_write_chunks() to send the Reply chunk. That's OK in this case:
> the server Upper Layer typically marshals the Reply chunk contents
> in a single contiguous buffer, without a separate tail for the XDR
> pad.
>
> The comments and the variable naming refer to "chunks" but what is
> really meant is "segments." The existing code sends only one
> xdr_write_chunk per RPC reply.
>
> The fix assumes this as well. When the XDR pad in the first write
> chunk is reached, the assumption is the Write list is complete and
> send_write_chunks() returns.
>
> That will remain a valid assumption until the server Upper Layer can
> support multiple bulk payload results per RPC.
>
> Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
> ---
> net/sunrpc/xprtrdma/svc_rdma_sendto.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index 1dfae83..6c48901 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -342,6 +342,13 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
> arg_ch->rs_handle,
> arg_ch->rs_offset,
> write_len);
> +
> + /* Do not send XDR pad bytes */
> + if (chunk_no && write_len < 4) {
> + chunk_no++;
> + break;
> + }
> +
> chunk_off = 0;
> while (write_len) {
> ret = send_write(xprt, rqstp,
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Chuck Lever
--
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WARNING: multiple messages have this Message-ID (diff)
From: Chuck Lever <chuck.lever@oracle.com>
To: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Linux RDMA Mailing List <linux-rdma@vger.kernel.org>,
Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Fwd: [PATCH] svcrdma: Do not send XDR roundup bytes for a write chunk
Date: Thu, 12 Nov 2015 09:47:13 -0500 [thread overview]
Message-ID: <648A8847-9836-42EC-9D62-77C01C6E9ACF@oracle.com> (raw)
In-Reply-To: 20151112144433.13507.34603.stgit@klimt.1015granger.net
I wish git send-mail had an address book. I’m really tired
of misspelling the to/cc addresses on patches.
Resending so there is one thread for all replies. Apologies
for the noise.
> Begin forwarded message:
>
> From: Chuck Lever <chuck.lever@oracle.com>
> Subject: [PATCH] svcrdma: Do not send XDR roundup bytes for a write chunk
> Date: November 12, 2015 at 9:44:33 AM EST
> To: bfields@fieldses.org
> Cc: linux-nfs@vger.kernel.org, linux-rmda@vger.kernel.org
>
> Minor optimization: when dealing with write chunk XDR roundup, do
> not post a Write WR for the zero bytes in the pad. Simply update
> the write segment in the RPC-over-RDMA header to reflect the extra
> pad bytes.
>
> The Reply chunk is also a write chunk, but the server does not use
> send_write_chunks() to send the Reply chunk. That's OK in this case:
> the server Upper Layer typically marshals the Reply chunk contents
> in a single contiguous buffer, without a separate tail for the XDR
> pad.
>
> The comments and the variable naming refer to "chunks" but what is
> really meant is "segments." The existing code sends only one
> xdr_write_chunk per RPC reply.
>
> The fix assumes this as well. When the XDR pad in the first write
> chunk is reached, the assumption is the Write list is complete and
> send_write_chunks() returns.
>
> That will remain a valid assumption until the server Upper Layer can
> support multiple bulk payload results per RPC.
>
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> net/sunrpc/xprtrdma/svc_rdma_sendto.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> index 1dfae83..6c48901 100644
> --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c
> @@ -342,6 +342,13 @@ static int send_write_chunks(struct svcxprt_rdma *xprt,
> arg_ch->rs_handle,
> arg_ch->rs_offset,
> write_len);
> +
> + /* Do not send XDR pad bytes */
> + if (chunk_no && write_len < 4) {
> + chunk_no++;
> + break;
> + }
> +
> chunk_off = 0;
> while (write_len) {
> ret = send_write(xprt, rqstp,
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
Chuck Lever
next prev parent reply other threads:[~2015-11-12 14:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-12 14:44 [PATCH] svcrdma: Do not send XDR roundup bytes for a write chunk Chuck Lever
2015-11-12 14:47 ` Chuck Lever [this message]
2015-11-12 14:47 ` Fwd: " Chuck Lever
[not found] ` <648A8847-9836-42EC-9D62-77C01C6E9ACF-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2015-11-12 15:17 ` J. Bruce Fields
2015-11-12 15:17 ` J. Bruce Fields
2015-11-12 18:30 ` Jason Gunthorpe
2015-11-12 18:30 ` Jason Gunthorpe
2015-11-12 19:13 ` J. Bruce Fields
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