Commit aee4b74a authored by Chuck Lever's avatar Chuck Lever

svcrdma: Fix double sync of transport header buffer

Performance optimization: Avoid syncing the transport buffer twice
when Reply buffer pull-up is necessary.
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 6fd5034d
......@@ -191,9 +191,6 @@ extern struct svc_rdma_send_ctxt *
extern void svc_rdma_send_ctxt_put(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt);
extern int svc_rdma_send(struct svcxprt_rdma *rdma, struct ib_send_wr *wr);
extern void svc_rdma_sync_reply_hdr(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt,
unsigned int len);
extern int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *sctxt,
const struct svc_rdma_recv_ctxt *rctxt,
......
......@@ -191,7 +191,6 @@ rpcrdma_bc_send_request(struct svcxprt_rdma *rdma, struct rpc_rqst *rqst)
*p++ = xdr_zero;
*p++ = xdr_zero;
*p = xdr_zero;
svc_rdma_sync_reply_hdr(rdma, ctxt, ctxt->sc_hdrbuf.len);
#ifdef SVCRDMA_BACKCHANNEL_DEBUG
pr_info("%s: %*ph\n", __func__, 64, rqst->rq_buffer);
......
......@@ -735,9 +735,9 @@ static void svc_rdma_send_error(struct svcxprt_rdma *xprt,
trace_svcrdma_err_chunk(*rdma_argp);
}
svc_rdma_sync_reply_hdr(xprt, ctxt, ctxt->sc_hdrbuf.len);
ctxt->sc_send_wr.num_sge = 1;
ctxt->sc_send_wr.opcode = IB_WR_SEND;
ctxt->sc_sges[0].length = ctxt->sc_hdrbuf.len;
ret = svc_rdma_send(xprt, &ctxt->sc_send_wr);
if (ret)
goto put_ctxt;
......
......@@ -301,6 +301,12 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct ib_send_wr *wr)
might_sleep();
/* Sync the transport header buffer */
ib_dma_sync_single_for_device(rdma->sc_pd->device,
wr->sg_list[0].addr,
wr->sg_list[0].length,
DMA_TO_DEVICE);
/* If the SQ is full, wait until an SQ entry is available */
while (1) {
if ((atomic_dec_return(&rdma->sc_sq_avail) < 0)) {
......@@ -532,24 +538,6 @@ static int svc_rdma_dma_map_buf(struct svcxprt_rdma *rdma,
offset_in_page(base), len);
}
/**
* svc_rdma_sync_reply_hdr - DMA sync the transport header buffer
* @rdma: controlling transport
* @ctxt: send_ctxt for the Send WR
* @len: length of transport header
*
*/
void svc_rdma_sync_reply_hdr(struct svcxprt_rdma *rdma,
struct svc_rdma_send_ctxt *ctxt,
unsigned int len)
{
ctxt->sc_sges[0].length = len;
ctxt->sc_send_wr.num_sge++;
ib_dma_sync_single_for_device(rdma->sc_pd->device,
ctxt->sc_sges[0].addr, len,
DMA_TO_DEVICE);
}
/**
* svc_rdma_pull_up_needed - Determine whether to use pull-up
* @rdma: controlling transport
......@@ -612,9 +600,7 @@ static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
unsigned char *dst, *tailbase;
unsigned int taillen;
dst = sctxt->sc_xprt_buf;
dst += sctxt->sc_sges[0].length;
dst = sctxt->sc_xprt_buf + sctxt->sc_hdrbuf.len;
memcpy(dst, xdr->head[0].iov_base, xdr->head[0].iov_len);
dst += xdr->head[0].iov_len;
......@@ -650,11 +636,6 @@ static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
memcpy(dst, tailbase, taillen);
sctxt->sc_sges[0].length += xdr->len;
ib_dma_sync_single_for_device(rdma->sc_pd->device,
sctxt->sc_sges[0].addr,
sctxt->sc_sges[0].length,
DMA_TO_DEVICE);
return 0;
}
......@@ -665,7 +646,7 @@ static int svc_rdma_pull_up_reply_msg(struct svcxprt_rdma *rdma,
* @xdr: prepared xdr_buf containing RPC message
*
* Load the xdr_buf into the ctxt's sge array, and DMA map each
* element as it is added.
* element as it is added. The Send WR's num_sge field is set.
*
* Returns zero on success, or a negative errno on failure.
*/
......@@ -681,6 +662,19 @@ int svc_rdma_map_reply_msg(struct svcxprt_rdma *rdma,
u32 xdr_pad;
int ret;
/* Set up the (persistently-mapped) transport header SGE. */
sctxt->sc_send_wr.num_sge = 1;
sctxt->sc_sges[0].length = sctxt->sc_hdrbuf.len;
/* If there is a Reply chunk, nothing follows the transport
* header, and we're done here.
*/
if (rctxt && rctxt->rc_reply_chunk)
return 0;
/* For pull-up, svc_rdma_send() will sync the transport header.
* No additional DMA mapping is necessary.
*/
if (svc_rdma_pull_up_needed(rdma, rctxt, xdr))
return svc_rdma_pull_up_reply_msg(rdma, sctxt, rctxt, xdr);
......@@ -782,12 +776,9 @@ static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma,
{
int ret;
if (!rctxt->rc_reply_chunk) {
ret = svc_rdma_map_reply_msg(rdma, sctxt, rctxt,
&rqstp->rq_res);
ret = svc_rdma_map_reply_msg(rdma, sctxt, rctxt, &rqstp->rq_res);
if (ret < 0)
return ret;
}
svc_rdma_save_io_pages(rqstp, sctxt);
......@@ -797,8 +788,6 @@ static int svc_rdma_send_reply_msg(struct svcxprt_rdma *rdma,
} else {
sctxt->sc_send_wr.opcode = IB_WR_SEND;
}
dprintk("svcrdma: posting Send WR with %u sge(s)\n",
sctxt->sc_send_wr.num_sge);
return svc_rdma_send(rdma, &sctxt->sc_send_wr);
}
......@@ -832,11 +821,11 @@ static int svc_rdma_send_error_msg(struct svcxprt_rdma *rdma,
*p = err_chunk;
trace_svcrdma_err_chunk(*rdma_argp);
svc_rdma_sync_reply_hdr(rdma, ctxt, ctxt->sc_hdrbuf.len);
svc_rdma_save_io_pages(rqstp, ctxt);
ctxt->sc_send_wr.num_sge = 1;
ctxt->sc_send_wr.opcode = IB_WR_SEND;
ctxt->sc_sges[0].length = ctxt->sc_hdrbuf.len;
return svc_rdma_send(rdma, &ctxt->sc_send_wr);
}
......@@ -921,7 +910,6 @@ int svc_rdma_sendto(struct svc_rqst *rqstp)
goto err0;
}
svc_rdma_sync_reply_hdr(rdma, sctxt, sctxt->sc_hdrbuf.len);
ret = svc_rdma_send_reply_msg(rdma, sctxt, rctxt, rqstp);
if (ret < 0)
goto err1;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment