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RDS: Add flag for silent ops. Do atomic op before RDMA 

Add a flag to the API so users can indicate they want
silent operations. This is needed because silent ops
cannot be used with USE_ONCE MRs, so we can't just
assume silent.

Also, change send_xmit to do atomic op before rdma op if
both are present, and centralize the hairy logic to determine if
we want to attempt silent, or not.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
This commit is contained in:
Andy Grover 2010-03-01 16:10:40 -08:00
parent 7e3bd65ebf
commit 2c3a5f9abb
4 changed files with 36 additions and 24 deletions
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1
include/linux/rds.h
View File

@ -276,5 +276,6 @@ struct rds_rdma_notify {
#define RDS_RDMA_USE_ONCE 0x0008 /* free MR after use */
#define RDS_RDMA_DONTWAIT 0x0010 /* Don't wait in SET_BARRIER */
#define RDS_RDMA_NOTIFY_ME 0x0020 /* Notify when operation completes */
#define RDS_RDMA_SILENT 0x0040 /* Do not interrupt remote */
#endif /* IB_RDS_H */

2
net/rds/rdma.c
View File

@ -559,6 +559,7 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm,
op->op_write = !!(args->flags & RDS_RDMA_READWRITE);
op->op_fence = !!(args->flags & RDS_RDMA_FENCE);
op->op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
op->op_silent = !!(args->flags & RDS_RDMA_SILENT);
op->op_active = 1;
op->op_recverr = rs->rs_recverr;
WARN_ON(!nr_pages);
@ -747,6 +748,7 @@ int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm,
}
rm->atomic.op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME);
rm->atomic.op_silent = !!(args->flags & RDS_RDMA_SILENT);
rm->atomic.op_active = 1;
rm->atomic.op_recverr = rs->rs_recverr;
rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1);

2
net/rds/rds.h
View File

@ -319,6 +319,7 @@ struct rds_message {
unsigned int op_notify:1;
unsigned int op_recverr:1;
unsigned int op_mapped:1;
unsigned int op_silent:1;
unsigned int op_active:1;
struct scatterlist *op_sg;
struct rds_notifier *op_notifier;
@ -333,6 +334,7 @@ struct rds_message {
unsigned int op_notify:1;
unsigned int op_recverr:1;
unsigned int op_mapped:1;
unsigned int op_silent:1;
unsigned int op_active:1;
unsigned int op_bytes;
unsigned int op_nents;

55
net/rds/send.c
View File

@ -250,6 +250,18 @@ int rds_send_xmit(struct rds_connection *conn)
conn->c_xmit_rm = rm;
}
/* The transport either sends the whole rdma or none of it */
if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
if (ret)
break;
conn->c_xmit_rdma_sent = 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 (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
ret = conn->c_trans->xmit_atomic(conn, rm);
if (ret)
@ -258,32 +270,28 @@ int rds_send_xmit(struct rds_connection *conn)
/* 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);
/*
* This is evil, muahaha.
* We permit 0-byte sends. (rds-ping depends on this.)
* BUT if there is an atomic op and no sent data,
* we turn off sending the header, to achieve
* "silent" atomics.
* But see below; RDMA op might toggle this back on!
*/
if (rm->data.op_nents == 0)
rm->data.op_active = 0;
}
/* The transport either sends the whole rdma or none of it */
if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
if (ret)
break;
conn->c_xmit_rdma_sent = 1;
/*
* A number of cases require an RDS header to be sent
* even if there is no data.
* We permit 0-byte sends; rds-ping depends on this.
* However, if there are exclusively attached silent ops,
* we skip the hdr/data send, to enable silent operation.
*/
if (rm->data.op_nents == 0) {
int ops_present;
int all_ops_are_silent = 1;
/* rdmas need data sent, even if just the header */
rm->data.op_active = 1;
ops_present = (rm->atomic.op_active || rm->rdma.op_active);
if (rm->atomic.op_active && !rm->atomic.op_silent)
all_ops_are_silent = 0;
if (rm->rdma.op_active && !rm->rdma.op_silent)
all_ops_are_silent = 0;
/* 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 (ops_present && all_ops_are_silent
&& !rm->m_rdma_cookie)
rm->data.op_active = 0;
}
if (rm->data.op_active && !conn->c_xmit_data_sent) {
@ -1009,8 +1017,7 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
if (ret)
goto out;
if ((rm->m_rdma_cookie || rm->rdma.op_active) &&
!conn->c_trans->xmit_rdma) {
if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
if (printk_ratelimit())
printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
&rm->rdma, conn->c_trans->xmit_rdma);