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>
This commit is contained in:
parent
1c00dd0776
commit
8301a2c047
|
@ -165,8 +165,9 @@ static int
|
||||||
rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
|
rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
|
||||||
{
|
{
|
||||||
struct ib_wc *wcs;
|
struct ib_wc *wcs;
|
||||||
int count, rc;
|
int budget, count, rc;
|
||||||
|
|
||||||
|
budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE;
|
||||||
do {
|
do {
|
||||||
wcs = ep->rep_send_wcs;
|
wcs = ep->rep_send_wcs;
|
||||||
|
|
||||||
|
@ -177,7 +178,7 @@ rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
|
||||||
count = rc;
|
count = rc;
|
||||||
while (count-- > 0)
|
while (count-- > 0)
|
||||||
rpcrdma_sendcq_process_wc(wcs++);
|
rpcrdma_sendcq_process_wc(wcs++);
|
||||||
} while (rc == RPCRDMA_POLLSIZE);
|
} while (rc == RPCRDMA_POLLSIZE && --budget);
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
@ -254,8 +255,9 @@ static int
|
||||||
rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
|
rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
|
||||||
{
|
{
|
||||||
struct ib_wc *wcs;
|
struct ib_wc *wcs;
|
||||||
int count, rc;
|
int budget, count, rc;
|
||||||
|
|
||||||
|
budget = RPCRDMA_WC_BUDGET / RPCRDMA_POLLSIZE;
|
||||||
do {
|
do {
|
||||||
wcs = ep->rep_recv_wcs;
|
wcs = ep->rep_recv_wcs;
|
||||||
|
|
||||||
|
@ -266,7 +268,7 @@ rpcrdma_recvcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep)
|
||||||
count = rc;
|
count = rc;
|
||||||
while (count-- > 0)
|
while (count-- > 0)
|
||||||
rpcrdma_recvcq_process_wc(wcs++);
|
rpcrdma_recvcq_process_wc(wcs++);
|
||||||
} while (rc == RPCRDMA_POLLSIZE);
|
} while (rc == RPCRDMA_POLLSIZE && --budget);
|
||||||
return 0;
|
return 0;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
|
@ -74,6 +74,7 @@ struct rpcrdma_ia {
|
||||||
* RDMA Endpoint -- one per transport instance
|
* RDMA Endpoint -- one per transport instance
|
||||||
*/
|
*/
|
||||||
|
|
||||||
|
#define RPCRDMA_WC_BUDGET (128)
|
||||||
#define RPCRDMA_POLLSIZE (16)
|
#define RPCRDMA_POLLSIZE (16)
|
||||||
|
|
||||||
struct rpcrdma_ep {
|
struct rpcrdma_ep {
|
||||||
|
|
Loading…
Reference in a new issue