diff options
Diffstat (limited to 'net/rds/send.c')
| -rw-r--r-- | net/rds/send.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/net/rds/send.c b/net/rds/send.c index 44672befc0ee..e9430f537f9c 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -140,8 +140,11 @@ int rds_send_xmit(struct rds_connection *conn) struct scatterlist *sg; int ret = 0; LIST_HEAD(to_be_dropped); + int batch_count; + unsigned long send_gen = 0; restart: + batch_count = 0; /* * sendmsg calls here after having queued its message on the send @@ -157,6 +160,17 @@ restart: } /* + * we record the send generation after doing the xmit acquire. + * if someone else manages to jump in and do some work, we'll use + * this to avoid a goto restart farther down. + * + * The acquire_in_xmit() check above ensures that only one + * caller can increment c_send_gen at any time. + */ + conn->c_send_gen++; + send_gen = conn->c_send_gen; + + /* * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT, * we do the opposite to avoid races. */ @@ -202,6 +216,16 @@ restart: if (!rm) { unsigned int len; + batch_count++; + + /* we want to process as big a batch as we can, but + * we also want to avoid softlockups. If we've been + * through a lot of messages, lets back off and see + * if anyone else jumps in + */ + if (batch_count >= 1024) + goto over_batch; + spin_lock_irqsave(&conn->c_lock, flags); if (!list_empty(&conn->c_send_queue)) { @@ -357,9 +381,9 @@ restart: } } +over_batch: if (conn->c_trans->xmit_complete) conn->c_trans->xmit_complete(conn); - release_in_xmit(conn); /* Nuke any messages we decided not to retransmit. */ @@ -380,10 +404,15 @@ restart: * If the transport cannot continue (i.e ret != 0), then it must * call us when more room is available, such as from the tx * completion handler. + * + * We have an extra generation check here so that if someone manages + * to jump in after our release_in_xmit, we'll see that they have done + * some work and we will skip our goto */ if (ret == 0) { smp_mb(); - if (!list_empty(&conn->c_send_queue)) { + if (!list_empty(&conn->c_send_queue) && + send_gen == conn->c_send_gen) { rds_stats_inc(s_send_lock_queue_raced); goto restart; } |