RDS: Implement silent atomics
Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/ib.h b/net/rds/ib.h
index 1488181..96769b8 100644
--- a/net/rds/ib.h
+++ b/net/rds/ib.h
@@ -336,7 +336,7 @@
void rds_ib_advertise_credits(struct rds_connection *conn, unsigned int posted);
int rds_ib_send_grab_credits(struct rds_ib_connection *ic, u32 wanted,
u32 *adv_credits, int need_posted, int max_posted);
-int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op);
+int rds_ib_xmit_atomic(struct rds_connection *conn, struct rds_message *rm);
/* ib_stats.c */
DECLARE_PER_CPU(struct rds_ib_statistics, rds_ib_stats);
diff --git a/net/rds/ib_send.c b/net/rds/ib_send.c
index d839b40..e6745d8 100644
--- a/net/rds/ib_send.c
+++ b/net/rds/ib_send.c
@@ -225,15 +225,12 @@
/* In the error case, wc.opcode sometimes contains garbage */
switch (send->s_wr.opcode) {
case IB_WR_SEND:
- if (send->s_rm)
- rds_ib_send_unmap_rm(ic, send, wc.status);
- break;
case IB_WR_RDMA_WRITE:
case IB_WR_RDMA_READ:
case IB_WR_ATOMIC_FETCH_AND_ADD:
case IB_WR_ATOMIC_CMP_AND_SWP:
- /* Nothing to be done - the SG list will be unmapped
- * when the SEND completes. */
+ if (send->s_rm)
+ rds_ib_send_unmap_rm(ic, send, wc.status);
break;
default:
if (printk_ratelimit())
@@ -425,6 +422,21 @@
set_bit(IB_ACK_REQUESTED, &ic->i_ack_flags);
}
+static inline void rds_ib_set_wr_signal_state(struct rds_ib_connection *ic,
+ struct rds_ib_send_work *send,
+ bool notify)
+{
+ /*
+ * We want to delay signaling completions just enough to get
+ * the batching benefits but not so much that we create dead time
+ * on the wire.
+ */
+ if (ic->i_unsignaled_wrs-- == 0 || notify) {
+ ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
+ send->s_wr.send_flags |= IB_SEND_SIGNALED;
+ }
+}
+
/*
* This can be called multiple times for a given message. The first time
* we see a message we map its scatterlist into the IB device so that
@@ -517,7 +529,6 @@
rm->data.m_count = 0;
}
- ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
rds_message_addref(rm);
ic->i_rm = rm;
@@ -608,15 +619,7 @@
}
}
- /*
- * We want to delay signaling completions just enough to get
- * the batching benefits but not so much that we create dead time
- * on the wire.
- */
- if (ic->i_unsignaled_wrs-- == 0) {
- ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
- send->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
- }
+ rds_ib_set_wr_signal_state(ic, send, 0);
/*
* Always signal the last one if we're stopping due to flow control.
@@ -656,7 +659,7 @@
/* if we finished the message then send completion owns it */
if (scat == &rm->data.m_sg[rm->data.m_count]) {
prev->s_rm = ic->i_rm;
- prev->s_wr.send_flags |= IB_SEND_SIGNALED | IB_SEND_SOLICITED;
+ prev->s_wr.send_flags |= IB_SEND_SOLICITED;
ic->i_rm = NULL;
}
@@ -698,9 +701,10 @@
* A simplified version of the rdma case, we always map 1 SG, and
* only 8 bytes, for the return value from the atomic operation.
*/
-int rds_ib_xmit_atomic(struct rds_connection *conn, struct rm_atomic_op *op)
+int rds_ib_xmit_atomic(struct rds_connection *conn, struct rds_message *rm)
{
struct rds_ib_connection *ic = conn->c_transport_data;
+ struct rm_atomic_op *op = &rm->atomic;
struct rds_ib_send_work *send = NULL;
struct ib_send_wr *failed_wr;
struct rds_ib_device *rds_ibdev;
@@ -731,12 +735,20 @@
send->s_wr.wr.atomic.compare_add = op->op_swap_add;
send->s_wr.wr.atomic.swap = 0;
}
- send->s_wr.send_flags = IB_SEND_SIGNALED;
+ rds_ib_set_wr_signal_state(ic, send, op->op_notify);
send->s_wr.num_sge = 1;
send->s_wr.next = NULL;
send->s_wr.wr.atomic.remote_addr = op->op_remote_addr;
send->s_wr.wr.atomic.rkey = op->op_rkey;
+ /*
+ * If there is no data or rdma ops in the message, then
+ * we must fill in s_rm ourselves, so we properly clean up
+ * on completion.
+ */
+ if (!rm->rdma.m_rdma_op.r_active && !rm->data.op_active)
+ send->s_rm = rm;
+
/* map 8 byte retval buffer to the device */
ret = ib_dma_map_sg(ic->i_cm_id->device, op->op_sg, 1, DMA_FROM_DEVICE);
rdsdebug("ic %p mapping atomic op %p. mapped %d pg\n", ic, op, ret);
@@ -836,14 +848,8 @@
for (i = 0; i < work_alloc && scat != &op->r_sg[op->r_count]; i++) {
send->s_wr.send_flags = 0;
send->s_queued = jiffies;
- /*
- * We want to delay signaling completions just enough to get
- * the batching benefits but not so much that we create dead time on the wire.
- */
- if (ic->i_unsignaled_wrs-- == 0) {
- ic->i_unsignaled_wrs = rds_ib_sysctl_max_unsig_wrs;
- send->s_wr.send_flags = IB_SEND_SIGNALED;
- }
+
+ rds_ib_set_wr_signal_state(ic, send, op->r_notify);
send->s_wr.opcode = op->r_write ? IB_WR_RDMA_WRITE : IB_WR_RDMA_READ;
send->s_wr.wr.rdma.remote_addr = remote_addr;
@@ -884,10 +890,6 @@
send = ic->i_sends;
}
- /* if we finished the message then send completion owns it */
- if (scat == &op->r_sg[op->r_count])
- prev->s_wr.send_flags = IB_SEND_SIGNALED;
-
if (i < work_alloc) {
rds_ib_ring_unalloc(&ic->i_send_ring, work_alloc - i);
work_alloc = i;
diff --git a/net/rds/message.c b/net/rds/message.c
index 3ea05c8..a27e493 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c
@@ -325,6 +325,8 @@
sg++;
}
+ rm->data.op_active = 1;
+
out:
return ret;
}
diff --git a/net/rds/rds.h b/net/rds/rds.h
index 0c610a1..bf2349da 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -341,6 +341,7 @@
struct rds_mr *m_rdma_mr;
} rdma;
struct rm_data_op {
+ unsigned int op_active:1;
unsigned int m_nents;
unsigned int m_count;
struct scatterlist *m_sg;
@@ -418,7 +419,7 @@
int (*xmit_cong_map)(struct rds_connection *conn,
struct rds_cong_map *map, unsigned long offset);
int (*xmit_rdma)(struct rds_connection *conn, struct rds_rdma_op *op);
- int (*xmit_atomic)(struct rds_connection *conn, struct rm_atomic_op *op);
+ int (*xmit_atomic)(struct rds_connection *conn, struct rds_message *rm);
int (*recv)(struct rds_connection *conn);
int (*inc_copy_to_user)(struct rds_incoming *inc, struct iovec *iov,
size_t size);
diff --git a/net/rds/send.c b/net/rds/send.c
index 5bc35d2..42fb934 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -266,7 +266,7 @@
if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
- ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
+ ret = conn->c_trans->xmit_atomic(conn, rm);
if (ret)
break;
conn->c_xmit_atomic_sent = 1;
@@ -285,13 +285,18 @@
if (ret)
break;
conn->c_xmit_rdma_sent = 1;
+
+ /* rdmas need data sent, even if just the header */
+ rm->data.op_active = 1;
+
/* The transport owns the mapped memory for now.
* You can't unmap it while it's on the send queue */
set_bit(RDS_MSG_MAPPED, &rm->m_flags);
}
- if (conn->c_xmit_hdr_off < sizeof(struct rds_header) ||
- conn->c_xmit_sg < rm->data.m_nents) {
+ if (rm->data.op_active
+ && (conn->c_xmit_hdr_off < sizeof(struct rds_header) ||
+ conn->c_xmit_sg < rm->data.m_nents)) {
ret = conn->c_trans->xmit(conn, rm,
conn->c_xmit_hdr_off,
conn->c_xmit_sg,