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xprtrdma: Use new CQ API for RPC-over-RDMA client send CQs

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Calling ib_poll_cq() to sort through WCs during a completion is a
common pattern amongst RDMA consumers. Since commit 14d3a3b249
("IB: add a proper completion queue abstraction"), WC sorting can
be handled by the IB core.

By converting to this new API, xprtrdma is made a better neighbor to
other RDMA consumers, as it allows the core to schedule the delivery
of completions more fairly amongst all active consumers.

Because each ib_cqe carries a pointer to a completion method, the
core can now post its own operations on a consumer's QP, and handle
the completions itself, without changes to the consumer.

Send completions were previously handled entirely in the completion
upcall handler (ie, deferring to a process context is unneeded).
Thus IB_POLL_SOFTIRQ is a direct replacement for the current
xprtrdma send code path.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Devesh Sharma <devesh.sharma@broadcom.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever
2016-03-04 11:28:53 -05:00
committed by Anna Schumaker
parent c882a655b7
commit 2fa8f88d88
3 changed files with 94 additions and 128 deletions
Download Patch File Download Diff File Expand all files Collapse all files

107
net/sunrpc/xprtrdma/verbs.c
View File

@@ -112,73 +112,20 @@ rpcrdma_qp_async_error_upcall(struct ib_event *event, void *context)
}
}
static void
rpcrdma_cq_async_error_upcall(struct ib_event *event, void *context)
{
struct rpcrdma_ep *ep = context;
pr_err("RPC: %s: %s on device %s ep %p\n",
__func__, ib_event_msg(event->event),
event->device->name, context);
if (ep->rep_connected == 1) {
ep->rep_connected = -EIO;
rpcrdma_conn_func(ep);
wake_up_all(&ep->rep_connect_wait);
}
}
static void
rpcrdma_sendcq_process_wc(struct ib_wc *wc)
{
/* WARNING: Only wr_id and status are reliable at this point */
if (wc->wr_id == RPCRDMA_IGNORE_COMPLETION) {
if (wc->status != IB_WC_SUCCESS &&
wc->status != IB_WC_WR_FLUSH_ERR)
pr_err("RPC: %s: SEND: %s\n",
__func__, ib_wc_status_msg(wc->status));
} else {
struct rpcrdma_mw *r;
r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
r->mw_sendcompletion(wc);
}
}
/* The common case is a single send completion is waiting. By
* passing two WC entries to ib_poll_cq, a return code of 1
* means there is exactly one WC waiting and no more. We don't
* have to invoke ib_poll_cq again to know that the CQ has been
* properly drained.
/**
* rpcrdma_wc_send - Invoked by RDMA provider for each polled Send WC
* @cq: completion queue (ignored)
* @wc: completed WR
*
*/
static void
rpcrdma_sendcq_poll(struct ib_cq *cq)
rpcrdma_wc_send(struct ib_cq *cq, struct ib_wc *wc)
{
struct ib_wc *pos, wcs[2];
int count, rc;
do {
pos = wcs;
rc = ib_poll_cq(cq, ARRAY_SIZE(wcs), pos);
if (rc < 0)
break;
count = rc;
while (count-- > 0)
rpcrdma_sendcq_process_wc(pos++);
} while (rc == ARRAY_SIZE(wcs));
return;
}
/* Handle provider send completion upcalls.
*/
static void
rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context)
{
do {
rpcrdma_sendcq_poll(cq);
} while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP |
IB_CQ_REPORT_MISSED_EVENTS) > 0);
/* WARNING: Only wr_cqe and status are reliable at this point */
if (wc->status != IB_WC_SUCCESS && wc->status != IB_WC_WR_FLUSH_ERR)
pr_err("rpcrdma: Send: %s (%u/0x%x)\n",
ib_wc_status_msg(wc->status),
wc->status, wc->vendor_err);
}
static void
@@ -263,8 +210,6 @@ rpcrdma_flush_cqs(struct rpcrdma_ep *ep)
while (ib_poll_cq(ep->rep_attr.recv_cq, 1, &wc) > 0)
rpcrdma_receive_wc(NULL, &wc);
while (ib_poll_cq(ep->rep_attr.send_cq, 1, &wc) > 0)
rpcrdma_sendcq_process_wc(&wc);
}
static int
@@ -556,9 +501,8 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
struct rpcrdma_create_data_internal *cdata)
{
struct ib_cq *sendcq, *recvcq;
struct ib_cq_init_attr cq_attr = {};
unsigned int max_qp_wr;
int rc, err;
int rc;
if (ia->ri_device->attrs.max_sge < RPCRDMA_MAX_IOVS) {
dprintk("RPC: %s: insufficient sge's available\n",
@@ -610,9 +554,9 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
init_waitqueue_head(&ep->rep_connect_wait);
INIT_DELAYED_WORK(&ep->rep_connect_worker, rpcrdma_connect_worker);
cq_attr.cqe = ep->rep_attr.cap.max_send_wr + 1;
sendcq = ib_create_cq(ia->ri_device, rpcrdma_sendcq_upcall,
rpcrdma_cq_async_error_upcall, NULL, &cq_attr);
sendcq = ib_alloc_cq(ia->ri_device, NULL,
ep->rep_attr.cap.max_send_wr + 1,
0, IB_POLL_SOFTIRQ);
if (IS_ERR(sendcq)) {
rc = PTR_ERR(sendcq);
dprintk("RPC: %s: failed to create send CQ: %i\n",
@@ -620,13 +564,6 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
goto out1;
}
rc = ib_req_notify_cq(sendcq, IB_CQ_NEXT_COMP);
if (rc) {
dprintk("RPC: %s: ib_req_notify_cq failed: %i\n",
__func__, rc);
goto out2;
}
recvcq = ib_alloc_cq(ia->ri_device, NULL,
ep->rep_attr.cap.max_recv_wr + 1,
0, IB_POLL_SOFTIRQ);
@@ -661,10 +598,7 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
return 0;
out2:
err = ib_destroy_cq(sendcq);
if (err)
dprintk("RPC: %s: ib_destroy_cq returned %i\n",
__func__, err);
ib_free_cq(sendcq);
out1:
if (ia->ri_dma_mr)
ib_dereg_mr(ia->ri_dma_mr);
@@ -700,11 +634,7 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
}
ib_free_cq(ep->rep_attr.recv_cq);
rc = ib_destroy_cq(ep->rep_attr.send_cq);
if (rc)
dprintk("RPC: %s: ib_destroy_cq returned %i\n",
__func__, rc);
ib_free_cq(ep->rep_attr.send_cq);
if (ia->ri_dma_mr) {
rc = ib_dereg_mr(ia->ri_dma_mr);
@@ -883,6 +813,7 @@ rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
spin_lock(&buffer->rb_reqslock);
list_add(&req->rl_all, &buffer->rb_allreqs);
spin_unlock(&buffer->rb_reqslock);
req->rl_cqe.done = rpcrdma_wc_send;
req->rl_buffer = &r_xprt->rx_buf;
return req;
}
@@ -1246,7 +1177,7 @@ rpcrdma_ep_post(struct rpcrdma_ia *ia,
}
send_wr.next = NULL;
send_wr.wr_id = RPCRDMA_IGNORE_COMPLETION;
send_wr.wr_cqe = &req->rl_cqe;
send_wr.sg_list = iov;
send_wr.num_sge = req->rl_niovs;
send_wr.opcode = IB_WR_SEND;