[lustre-devel] [PATCH 01/13] lnet: Allow delayed sends

[James Simmons]

From: Chris Horn <chris.horn at hpe.com>

The net_delay_add has some code related to delaying sends, but it
isn't fully implemented. Modify lnet_post_send_locked() to check
whether the message being sent matches a rule and should be delayed.

Fix some bugs with how the delay timers were set and checked.

HPE-bug-id: LUS-7651
WC-bug-id: https://jira.whamcloud.com/browse/LU-14627
Lustre-commit: ab14f3bc852e7081 ("LU-14627 lnet: Allow delayed sends")
Signed-off-by: Chris Horn <chris.horn at hpe.com>
Reviewed-on: https://review.whamcloud.com/43416
Reviewed-by: Serguei Smirnov <ssmirnov at whamcloud.com>
Reviewed-by: James Simmons <jsimmons at infradead.org>
Reviewed-by: Oleg Drokin <green at whamcloud.com>
Signed-off-by: James Simmons <jsimmons at infradead.org>
---
 include/linux/lnet/lib-lnet.h |  1 +
 net/lnet/lnet/lib-move.c      |  8 +++++++-
 net/lnet/lnet/net_fault.c     | 24 +++++++++++++++++++-----
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/include/linux/lnet/lib-lnet.h b/include/linux/lnet/lib-lnet.h
index 674f9d1..6b9e926 100644
--- a/include/linux/lnet/lib-lnet.h
+++ b/include/linux/lnet/lib-lnet.h
@@ -630,6 +630,7 @@ void lnet_recv(struct lnet_ni *ni, void *private, struct lnet_msg *msg,
 void lnet_ni_recv(struct lnet_ni *ni, void *private, struct lnet_msg *msg,
 		  int delayed, unsigned int offset,
 		  unsigned int mlen, unsigned int rlen);
+void lnet_ni_send(struct lnet_ni *ni, struct lnet_msg *msg);
 
 struct lnet_msg *lnet_create_reply_msg(struct lnet_ni *ni,
 				       struct lnet_msg *get_msg);
diff --git a/net/lnet/lnet/lib-move.c b/net/lnet/lnet/lib-move.c
index cb0943e..6d0637c 100644
--- a/net/lnet/lnet/lib-move.c
+++ b/net/lnet/lnet/lib-move.c
@@ -530,7 +530,7 @@ void lnet_usr_translate_stats(struct lnet_ioctl_element_msg_stats *msg_stats,
 	msg->msg_hdr.payload_length = cpu_to_le32(len);
 }
 
-static void
+void
 lnet_ni_send(struct lnet_ni *ni, struct lnet_msg *msg)
 {
 	void *priv = msg->msg_private;
@@ -733,6 +733,12 @@ void lnet_usr_translate_stats(struct lnet_ioctl_element_msg_stats *msg_stats,
 		}
 	}
 
+	if (unlikely(!list_empty(&the_lnet.ln_delay_rules)) &&
+	    lnet_delay_rule_match_locked(&msg->msg_hdr, msg)) {
+		msg->msg_tx_delayed = 1;
+		return LNET_CREDIT_WAIT;
+	}
+
 	/* unset the tx_delay flag as we're going to send it now */
 	msg->msg_tx_delayed = 0;
 
diff --git a/net/lnet/lnet/net_fault.c b/net/lnet/lnet/net_fault.c
index 515aa05..0d19da4 100644
--- a/net/lnet/lnet/net_fault.c
+++ b/net/lnet/lnet/net_fault.c
@@ -536,6 +536,7 @@ struct delay_daemon_data {
 {
 	struct lnet_fault_attr *attr = &rule->dl_attr;
 	bool delay;
+	time64_t now = ktime_get_seconds();
 
 	if (!lnet_fault_attr_match(attr, src, LNET_NID_ANY,
 				   dst, type, portal))
@@ -544,8 +545,6 @@ struct delay_daemon_data {
 	/* match this rule, check delay rate now */
 	spin_lock(&rule->dl_lock);
 	if (rule->dl_delay_time) { /* time based delay */
-		time64_t now = ktime_get_seconds();
-
 		rule->dl_stat.fs_count++;
 		delay = now >= rule->dl_delay_time;
 		if (delay) {
@@ -587,10 +586,11 @@ struct delay_daemon_data {
 	rule->dl_stat.u.delay.ls_delayed++;
 
 	list_add_tail(&msg->msg_list, &rule->dl_msg_list);
-	msg->msg_delay_send = ktime_get_seconds() + attr->u.delay.la_latency;
+	msg->msg_delay_send = now + attr->u.delay.la_latency;
 	if (rule->dl_msg_send == -1) {
 		rule->dl_msg_send = msg->msg_delay_send;
-		mod_timer(&rule->dl_timer, jiffies + rule->dl_msg_send * HZ);
+		mod_timer(&rule->dl_timer,
+			  jiffies + attr->u.delay.la_latency * HZ);
 	}
 
 	spin_unlock(&rule->dl_lock);
@@ -662,7 +662,8 @@ struct delay_daemon_data {
 		msg = list_first_entry(&rule->dl_msg_list,
 				       struct lnet_msg, msg_list);
 		rule->dl_msg_send = msg->msg_delay_send;
-		mod_timer(&rule->dl_timer, jiffies + rule->dl_msg_send * HZ);
+		mod_timer(&rule->dl_timer,
+			  jiffies + (msg->msg_delay_send - now) * HZ);
 	}
 	spin_unlock(&rule->dl_lock);
 }
@@ -678,6 +679,19 @@ struct delay_daemon_data {
 		int cpt;
 		int rc;
 
+		if (msg->msg_sending) {
+			/* Delayed send */
+			list_del_init(&msg->msg_list);
+			ni = msg->msg_txni;
+			CDEBUG(D_NET, "TRACE: msg %p %s -> %s : %s\n", msg,
+			       libcfs_nid2str(ni->ni_nid),
+			       libcfs_nid2str(msg->msg_txpeer->lpni_nid),
+			       lnet_msgtyp2str(msg->msg_type));
+			lnet_ni_send(ni, msg);
+			continue;
+		}
+
+		/* Delayed receive */
 		LASSERT(msg->msg_rxpeer);
 		LASSERT(msg->msg_rxni);
 
-- 
1.8.3.1