| Message ID | 20151006145851.11788.95912.stgit@manet.1015granger.net (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
Looks good, Reviewed-By: Devesh Sharma <devesh.sharma@avagotech.com> Will send a test-report of this series with ocrdma drivers. On Tue, Oct 6, 2015 at 8:28 PM, Chuck Lever <chuck.lever@oracle.com> wrote: > ib_req_notify_cq(IB_CQ_REPORT_MISSED_EVENTS) returns a positive > value if WCs were added to a CQ after the last completion upcall > but before the CQ has been re-armed. > > Commit 7f23f6f6e388 ("xprtrmda: Reduce lock contention in > completion handlers") assumed that when ib_req_notify_cq() returned > a positive RC, the CQ had also been successfully re-armed, making > it safe to return control to the provider without losing any > completion signals. That is an invalid assumption. > > Change both completion handlers to continue polling while > ib_req_notify_cq() returns a positive value. > > Fixes: 7f23f6f6e388 ("xprtrmda: Reduce lock contention in ...") > Signed-off-by: Chuck Lever <chuck.lever@oracle.com> > --- > net/sunrpc/xprtrdma/verbs.c | 66 +++++++------------------------------------ > 1 file changed, 10 insertions(+), 56 deletions(-) > > diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c > index 8a477e2..c713909 100644 > --- a/net/sunrpc/xprtrdma/verbs.c > +++ b/net/sunrpc/xprtrdma/verbs.c > @@ -179,38 +179,17 @@ rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) > return 0; > } > > -/* > - * Handle send, fast_reg_mr, and local_inv completions. > - * > - * Send events are typically suppressed and thus do not result > - * in an upcall. Occasionally one is signaled, however. This > - * prevents the provider's completion queue from wrapping and > - * losing a completion. > +/* Handle provider send completion upcalls. > */ > static void > rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context) > { > struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; > - int rc; > - > - rc = rpcrdma_sendcq_poll(cq, ep); > - if (rc) { > - dprintk("RPC: %s: ib_poll_cq failed: %i\n", > - __func__, rc); > - return; > - } > > - rc = ib_req_notify_cq(cq, > - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); > - if (rc == 0) > - return; > - if (rc < 0) { > - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", > - __func__, rc); > - return; > - } > - > - rpcrdma_sendcq_poll(cq, ep); > + do { > + rpcrdma_sendcq_poll(cq, ep); > + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | > + IB_CQ_REPORT_MISSED_EVENTS) > 0); > } > > static void > @@ -274,42 +253,17 @@ out_schedule: > return rc; > } > > -/* > - * Handle receive completions. > - * > - * It is reentrant but processes single events in order to maintain > - * ordering of receives to keep server credits. > - * > - * It is the responsibility of the scheduled tasklet to return > - * recv buffers to the pool. NOTE: this affects synchronization of > - * connection shutdown. That is, the structures required for > - * the completion of the reply handler must remain intact until > - * all memory has been reclaimed. > +/* Handle provider receive completion upcalls. > */ > static void > rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context) > { > struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; > - int rc; > - > - rc = rpcrdma_recvcq_poll(cq, ep); > - if (rc) { > - dprintk("RPC: %s: ib_poll_cq failed: %i\n", > - __func__, rc); > - return; > - } > > - rc = ib_req_notify_cq(cq, > - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); > - if (rc == 0) > - return; > - if (rc < 0) { > - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", > - __func__, rc); > - return; > - } > - > - rpcrdma_recvcq_poll(cq, ep); > + do { > + rpcrdma_recvcq_poll(cq, ep); > + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | > + IB_CQ_REPORT_MISSED_EVENTS) > 0); > } > > static void > > -- > To unsubscribe from this list: send the line "unsubscribe linux-rdma" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 8a477e2..c713909 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -179,38 +179,17 @@ rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) return 0; } -/* - * Handle send, fast_reg_mr, and local_inv completions. - * - * Send events are typically suppressed and thus do not result - * in an upcall. Occasionally one is signaled, however. This - * prevents the provider's completion queue from wrapping and - * losing a completion. +/* Handle provider send completion upcalls. */ static void rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context) { struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; - int rc; - - rc = rpcrdma_sendcq_poll(cq, ep); - if (rc) { - dprintk("RPC: %s: ib_poll_cq failed: %i\n", - __func__, rc); - return; - } - rc = ib_req_notify_cq(cq, - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); - if (rc == 0) - return; - if (rc < 0) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - return; - } - - rpcrdma_sendcq_poll(cq, ep); + do { + rpcrdma_sendcq_poll(cq, ep); + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | + IB_CQ_REPORT_MISSED_EVENTS) > 0); } static void @@ -274,42 +253,17 @@ out_schedule: return rc; } -/* - * Handle receive completions. - * - * It is reentrant but processes single events in order to maintain - * ordering of receives to keep server credits. - * - * It is the responsibility of the scheduled tasklet to return - * recv buffers to the pool. NOTE: this affects synchronization of - * connection shutdown. That is, the structures required for - * the completion of the reply handler must remain intact until - * all memory has been reclaimed. +/* Handle provider receive completion upcalls. */ static void rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context) { struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; - int rc; - - rc = rpcrdma_recvcq_poll(cq, ep); - if (rc) { - dprintk("RPC: %s: ib_poll_cq failed: %i\n", - __func__, rc); - return; - } - rc = ib_req_notify_cq(cq, - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); - if (rc == 0) - return; - if (rc < 0) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - return; - } - - rpcrdma_recvcq_poll(cq, ep); + do { + rpcrdma_recvcq_poll(cq, ep); + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | + IB_CQ_REPORT_MISSED_EVENTS) > 0); } static void
ib_req_notify_cq(IB_CQ_REPORT_MISSED_EVENTS) returns a positive value if WCs were added to a CQ after the last completion upcall but before the CQ has been re-armed. Commit 7f23f6f6e388 ("xprtrmda: Reduce lock contention in completion handlers") assumed that when ib_req_notify_cq() returned a positive RC, the CQ had also been successfully re-armed, making it safe to return control to the provider without losing any completion signals. That is an invalid assumption. Change both completion handlers to continue polling while ib_req_notify_cq() returns a positive value. Fixes: 7f23f6f6e388 ("xprtrmda: Reduce lock contention in ...") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> --- net/sunrpc/xprtrdma/verbs.c | 66 +++++++------------------------------------ 1 file changed, 10 insertions(+), 56 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html