diff options
author | Chuck Lever <chuck.lever@oracle.com> | 2015-01-21 11:03:02 -0500 |
---|---|---|
committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2015-01-30 10:47:48 -0500 |
commit | eba8ff660b2d8b7fcd6669fcab2c025b59f66d26 (patch) | |
tree | 7a9a00e875d14cad14e389998a0f3cfbdfc94b83 /net/sunrpc/xprtrdma/verbs.c | |
parent | 3eb358106660195948f4e95822039c5799fc41f8 (diff) |
xprtrdma: Move credit update to RPC reply handler
Reduce work in the receive CQ handler, which can be run at hardware
interrupt level, by moving the RPC/RDMA credit update logic to the
RPC reply handler.
This has some additional benefits: More header sanity checking is
done before trusting the incoming credit value, and the receive CQ
handler no longer touches the RPC/RDMA header (the CPU stalls while
waiting for the header contents to be brought into the cache).
This further extends work begun by commit e7ce710a8802 ("xprtrdma:
Avoid deadlock when credit window is reset").
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Diffstat (limited to 'net/sunrpc/xprtrdma/verbs.c')
-rw-r--r-- | net/sunrpc/xprtrdma/verbs.c | 15 |
1 files changed, 2 insertions, 13 deletions
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 1000f637edee..71a071aaf0ab 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -49,6 +49,7 @@ #include <linux/interrupt.h> #include <linux/slab.h> +#include <linux/prefetch.h> #include <asm/bitops.h> #include "xprt_rdma.h" @@ -298,17 +299,7 @@ rpcrdma_recvcq_process_wc(struct ib_wc *wc, struct list_head *sched_list) rep->rr_len = wc->byte_len; ib_dma_sync_single_for_cpu(rdmab_to_ia(rep->rr_buffer)->ri_id->device, rep->rr_iov.addr, rep->rr_len, DMA_FROM_DEVICE); - - if (rep->rr_len >= 16) { - struct rpcrdma_msg *p = (struct rpcrdma_msg *)rep->rr_base; - unsigned int credits = ntohl(p->rm_credit); - - if (credits == 0) - credits = 1; /* don't deadlock */ - else if (credits > rep->rr_buffer->rb_max_requests) - credits = rep->rr_buffer->rb_max_requests; - atomic_set(&rep->rr_buffer->rb_credits, credits); - } + prefetch(rep->rr_base); out_schedule: list_add_tail(&rep->rr_list, sched_list); @@ -480,7 +471,6 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event) case RDMA_CM_EVENT_DEVICE_REMOVAL: connstate = -ENODEV; connected: - atomic_set(&rpcx_to_rdmax(ep->rep_xprt)->rx_buf.rb_credits, 1); dprintk("RPC: %s: %sconnected\n", __func__, connstate > 0 ? "" : "dis"); ep->rep_connected = connstate; @@ -1186,7 +1176,6 @@ rpcrdma_buffer_create(struct rpcrdma_buffer *buf, struct rpcrdma_ep *ep, buf->rb_max_requests = cdata->max_requests; spin_lock_init(&buf->rb_lock); - atomic_set(&buf->rb_credits, 1); /* Need to allocate: * 1. arrays for send and recv pointers |