patch 'event/dlb2: rework queue drain handling' has been queued to stable release 21.11.2

[Kevin Traynor]

Hi,

FYI, your patch has been queued to stable release 21.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 06/27/22. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable/commit/7c0439f319503ced6777f3e0d2da213ead816b79

Thanks.

Kevin

---
>From 7c0439f319503ced6777f3e0d2da213ead816b79 Mon Sep 17 00:00:00 2001
From: Timothy McDaniel <timothy.mcdaniel at intel.com>
Date: Mon, 6 Jun 2022 10:55:17 -0500
Subject: [PATCH] event/dlb2: rework queue drain handling

[ upstream commit 82a710bccb209f7b5b0309f687741102f093234f ]

Previously, anything that prevented the CQs from being drained
would hang the PMD for an unacceptably long time. This commit updates
the drain logic to be resource and time based, thus eliminating
the potential for a long hang when draining the queues in preparation
for a reset.

Fixes: 1857f1922ce2 ("event/dlb2: use new implementation of resource file")

Signed-off-by: Timothy McDaniel <timothy.mcdaniel at intel.com>
---
 drivers/event/dlb2/pf/base/dlb2_hw_types.h |  2 +-
 drivers/event/dlb2/pf/base/dlb2_resource.c | 45 +++++++++++++++++-----
 2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/drivers/event/dlb2/pf/base/dlb2_hw_types.h b/drivers/event/dlb2/pf/base/dlb2_hw_types.h
index 6b8fee3416..9511521e67 100644
--- a/drivers/event/dlb2/pf/base/dlb2_hw_types.h
+++ b/drivers/event/dlb2/pf/base/dlb2_hw_types.h
@@ -28,5 +28,5 @@
 #define DLB2_MAX_NUM_SEQUENCE_NUMBER_MODES	5
 #define DLB2_MAX_CQ_COMP_CHECK_LOOPS		409600
-#define DLB2_MAX_QID_EMPTY_CHECK_LOOPS		(32 * 64 * 1024 * (800 / 30))
+#define DLB2_MAX_QID_EMPTY_CHECK_LOOPS		(4 * DLB2_MAX_NUM_LDB_CREDITS)
 
 #define DLB2_FUNC_BAR				0
diff --git a/drivers/event/dlb2/pf/base/dlb2_resource.c b/drivers/event/dlb2/pf/base/dlb2_resource.c
index d4c49c2992..8c57bdfff7 100644
--- a/drivers/event/dlb2/pf/base/dlb2_resource.c
+++ b/drivers/event/dlb2/pf/base/dlb2_resource.c
@@ -1058,5 +1058,5 @@ static u32 dlb2_dir_cq_token_count(struct dlb2_hw *hw,
 }
 
-static void dlb2_drain_dir_cq(struct dlb2_hw *hw,
+static int dlb2_drain_dir_cq(struct dlb2_hw *hw,
 			      struct dlb2_dir_pq_pair *port)
 {
@@ -1090,4 +1090,6 @@ static void dlb2_drain_dir_cq(struct dlb2_hw *hw,
 		os_unmap_producer_port(hw, pp_addr);
 	}
+
+	return cnt;
 }
 
@@ -1108,4 +1110,5 @@ static int dlb2_domain_drain_dir_cqs(struct dlb2_hw *hw,
 	struct dlb2_list_entry *iter;
 	struct dlb2_dir_pq_pair *port;
+	int drain_cnt = 0;
 	RTE_SET_USED(iter);
 
@@ -1121,5 +1124,5 @@ static int dlb2_domain_drain_dir_cqs(struct dlb2_hw *hw,
 			dlb2_dir_port_cq_disable(hw, port);
 
-		dlb2_drain_dir_cq(hw, port);
+		drain_cnt = dlb2_drain_dir_cq(hw, port);
 
 		if (toggle_port)
@@ -1127,5 +1130,5 @@ static int dlb2_domain_drain_dir_cqs(struct dlb2_hw *hw,
 	}
 
-	return 0;
+	return drain_cnt;
 }
 
@@ -1171,8 +1174,18 @@ static int dlb2_domain_drain_dir_queues(struct dlb2_hw *hw,
 
 	for (i = 0; i < DLB2_MAX_QID_EMPTY_CHECK_LOOPS; i++) {
-		dlb2_domain_drain_dir_cqs(hw, domain, true);
+		int drain_cnt;
+
+		drain_cnt = dlb2_domain_drain_dir_cqs(hw, domain, false);
 
 		if (dlb2_domain_dir_queues_empty(hw, domain))
 			break;
+
+		/*
+		 * Allow time for DLB to schedule QEs before draining
+		 * the CQs again.
+		 */
+		if (!drain_cnt)
+			rte_delay_us(1);
+
 	}
 
@@ -1250,5 +1263,5 @@ static u32 dlb2_ldb_cq_token_count(struct dlb2_hw *hw,
 }
 
-static void dlb2_drain_ldb_cq(struct dlb2_hw *hw, struct dlb2_ldb_port *port)
+static int dlb2_drain_ldb_cq(struct dlb2_hw *hw, struct dlb2_ldb_port *port)
 {
 	u32 infl_cnt, tkn_cnt;
@@ -1290,7 +1303,9 @@ static void dlb2_drain_ldb_cq(struct dlb2_hw *hw, struct dlb2_ldb_port *port)
 		os_unmap_producer_port(hw, pp_addr);
 	}
+
+	return tkn_cnt;
 }
 
-static void dlb2_domain_drain_ldb_cqs(struct dlb2_hw *hw,
+static int dlb2_domain_drain_ldb_cqs(struct dlb2_hw *hw,
 				      struct dlb2_hw_domain *domain,
 				      bool toggle_port)
@@ -1298,4 +1313,5 @@ static void dlb2_domain_drain_ldb_cqs(struct dlb2_hw *hw,
 	struct dlb2_list_entry *iter;
 	struct dlb2_ldb_port *port;
+	int drain_cnt = 0;
 	int i;
 	RTE_SET_USED(iter);
@@ -1303,5 +1319,5 @@ static void dlb2_domain_drain_ldb_cqs(struct dlb2_hw *hw,
 	/* If the domain hasn't been started, there's no traffic to drain */
 	if (!domain->started)
-		return;
+		return 0;
 
 	for (i = 0; i < DLB2_NUM_COS_DOMAINS; i++) {
@@ -1310,5 +1326,5 @@ static void dlb2_domain_drain_ldb_cqs(struct dlb2_hw *hw,
 				dlb2_ldb_port_cq_disable(hw, port);
 
-			dlb2_drain_ldb_cq(hw, port);
+			drain_cnt = dlb2_drain_ldb_cq(hw, port);
 
 			if (toggle_port)
@@ -1316,4 +1332,6 @@ static void dlb2_domain_drain_ldb_cqs(struct dlb2_hw *hw,
 		}
 	}
+
+	return drain_cnt;
 }
 
@@ -1376,8 +1394,17 @@ static int dlb2_domain_drain_mapped_queues(struct dlb2_hw *hw,
 
 	for (i = 0; i < DLB2_MAX_QID_EMPTY_CHECK_LOOPS; i++) {
-		dlb2_domain_drain_ldb_cqs(hw, domain, true);
+		int drain_cnt;
+
+		drain_cnt = dlb2_domain_drain_ldb_cqs(hw, domain, false);
 
 		if (dlb2_domain_mapped_queues_empty(hw, domain))
 			break;
+
+		/*
+		 * Allow time for DLB to schedule QEs before draining
+		 * the CQs again.
+		 */
+		if (!drain_cnt)
+			rte_delay_us(1);
 	}
 
-- 
2.34.3

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2022-06-24 15:51:09.576609319 +0100
+++ 0023-event-dlb2-rework-queue-drain-handling.patch	2022-06-24 15:51:08.889984130 +0100
@@ -1 +1 @@
-From 82a710bccb209f7b5b0309f687741102f093234f Mon Sep 17 00:00:00 2001
+From 7c0439f319503ced6777f3e0d2da213ead816b79 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 82a710bccb209f7b5b0309f687741102f093234f ]
+
@@ -13 +14,0 @@
-Cc: stable at dpdk.org