diff options
| author | Chuck Lever <chuck.lever@oracle.com> | 2014-05-28 10:33:51 -0400 |
|---|---|---|
| committer | Anna Schumaker <Anna.Schumaker@Netapp.com> | 2014-06-04 08:56:45 -0400 |
| commit | 8301a2c047cc25dabd645e5590c1db0ead4c5af4 (patch) | |
| tree | eb9901cc1585570fe8306d05d6d3b381662ef1ce | |
| parent | 1c00dd0776543608e13c74a527660cb8cd28a74f (diff) | |
xprtrdma: Limit work done by completion handler
Sagi Grimberg <sagig@dev.mellanox.co.il> points out that a steady
stream of CQ events could starve other work because of the boundless
loop pooling in rpcrdma_{send,recv}_poll().
Instead of a (potentially infinite) while loop, return after
collecting a budgeted number of completions.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Acked-by: Sagi Grimberg <sagig@dev.mellanox.co.il>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
| -rw-r--r-- | net/sunrpc/xprtrdma/verbs.c | 10 | ||||
| -rw-r--r-- | net/sunrpc/xprtrdma/xprt_rdma.h | 1 |
2 files changed, 7 insertions, 4 deletions
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index b8caee91661c..1d083664bfca 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -165,8 +165,9 @@ static int rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) { struct ib_wc *wcs; - int count, rc; + int budget, count, rc; + budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE; do { wcs = ep->rep_send_wcs; @@ -177,7 +178,7 @@ rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) count = rc; while (count-- > 0) rpcrdma_sendcq_process_wc(wcs++); - } while (rc == RPCRDMA_POLLSIZE); + } while (rc == RPCRDMA_POLLSIZE && --budget); return 0; } @@ -254,8 +255,9 @@ static int rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) { struct ib_wc *wcs; - int count, rc; + int budget, count, rc; + budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE; do { wcs = ep->rep_recv_wcs; @@ -266,7 +268,7 @@ rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) count = rc; while (count-- > 0) rpcrdma_recvcq_process_wc(wcs++); - } while (rc == RPCRDMA_POLLSIZE); + } while (rc == RPCRDMA_POLLSIZE && --budget); return 0; } diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index cb4c882b97fe..0c3b88ea5edb 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -74,6 +74,7 @@ struct rpcrdma_ia { * RDMA Endpoint -- one per transport instance */ +#define RPCRDMA_WC_BUDGET (128) #define RPCRDMA_POLLSIZE (16) struct rpcrdma_ep { |