[dpdk-stable] patch 'test/distributor: fix shutdown of busy worker' has been queued to LTS release 18.11.11

[Kevin Traynor]

Hi,

FYI, your patch has been queued to LTS release 18.11.11

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 11/24/20. 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-queue

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable-queue/commit/9759e36e4f000ff9b16a3681b3806b6c3efaf507

Thanks.

Kevin.

---
>From 9759e36e4f000ff9b16a3681b3806b6c3efaf507 Mon Sep 17 00:00:00 2001
From: Lukasz Wojciechowski <l.wojciechow at partner.samsung.com>
Date: Sat, 17 Oct 2020 05:06:49 +0200
Subject: [PATCH] test/distributor: fix shutdown of busy worker

[ upstream commit cf669d6930116b80493d67cdc5d7a1a568eed8e9 ]

The sanity test with worker shutdown delegates all bufs
to be processed by a single lcore worker, then it freezes
one of the lcore workers and continues to send more bufs.
The freezed core shuts down first by calling
rte_distributor_return_pkt().

The test intention is to verify if packets assigned to
the shut down lcore will be reassigned to another worker.

However the shutdown core was not always the one, that was
processing packets. The lcore processing mbufs might be different
every time test is launched. This is caused by keeping the value
of wkr static variable in rte_distributor_process() function
between running test cases.

Test freezed always lcore with 0 id. The patch stores the id
of worker that is processing the data in zero_idx global atomic
variable. This way the freezed lcore is always the proper one.

Fixes: c3eabff124e6 ("distributor: add unit tests")

Signed-off-by: Lukasz Wojciechowski <l.wojciechow at partner.samsung.com>
Tested-by: David Hunt <david.hunt at intel.com>
---
 test/test/test_distributor.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/test/test/test_distributor.c b/test/test/test_distributor.c
index ae7eff5a91..45b4b22b43 100644
--- a/test/test/test_distributor.c
+++ b/test/test/test_distributor.c
@@ -29,4 +29,5 @@ static volatile int quit;      /**< general quit variable for all threads */
 static volatile int zero_quit; /**< var for when we just want thr0 to quit*/
 static volatile unsigned worker_idx;
+static volatile unsigned zero_idx;
 
 struct worker_stats {
@@ -341,11 +342,20 @@ handle_work_for_shutdown_test(void *arg)
 	unsigned int i;
 	unsigned int returned = 0;
+	unsigned int zero_id = 0;
+	unsigned int zero_unset;
 	const unsigned int id = __sync_fetch_and_add(&worker_idx, 1);
 
 	num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
 
+	if (num > 0) {
+		zero_unset = RTE_MAX_LCORE;
+		__atomic_compare_exchange_n(&zero_idx, &zero_unset, id,
+			0, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
+	}
+	zero_id = __atomic_load_n(&zero_idx, __ATOMIC_ACQUIRE);
+
 	/* wait for quit single globally, or for worker zero, wait
 	 * for zero_quit */
-	while (!quit && !(id == 0 && zero_quit)) {
+	while (!quit && !(id == zero_id && zero_quit)) {
 		worker_stats[id].handled_packets += num;
 		count += num;
@@ -353,4 +363,12 @@ handle_work_for_shutdown_test(void *arg)
 			rte_pktmbuf_free(buf[i]);
 		num = rte_distributor_get_pkt(d, id, buf, NULL, 0);
+
+		if (num > 0) {
+			zero_unset = RTE_MAX_LCORE;
+			__atomic_compare_exchange_n(&zero_idx, &zero_unset, id,
+				0, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
+		}
+		zero_id = __atomic_load_n(&zero_idx, __ATOMIC_ACQUIRE);
+
 		total += num;
 	}
@@ -359,5 +377,5 @@ handle_work_for_shutdown_test(void *arg)
 	returned = rte_distributor_return_pkt(d, id, buf, num);
 
-	if (id == 0) {
+	if (id == zero_id) {
 		/* for worker zero, allow it to restart to pick up last packet
 		 * when all workers are shutting down.
@@ -578,4 +596,5 @@ quit_workers(struct worker_params *wp, struct rte_mempool *p)
 	quit = 0;
 	worker_idx = 0;
+	zero_idx = RTE_MAX_LCORE;
 }
 
-- 
2.26.2

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-11-18 16:33:38.387612492 +0000
+++ 0022-test-distributor-fix-shutdown-of-busy-worker.patch	2020-11-18 16:33:37.927215061 +0000
@@ -1 +1 @@
-From cf669d6930116b80493d67cdc5d7a1a568eed8e9 Mon Sep 17 00:00:00 2001
+From 9759e36e4f000ff9b16a3681b3806b6c3efaf507 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit cf669d6930116b80493d67cdc5d7a1a568eed8e9 ]
+
@@ -26 +27,0 @@
-Cc: stable at dpdk.org
@@ -31 +32 @@
- app/test/test_distributor.c | 23 +++++++++++++++++++++--
+ test/test/test_distributor.c | 23 +++++++++++++++++++++--
@@ -34,4 +35,4 @@
-diff --git a/app/test/test_distributor.c b/app/test/test_distributor.c
-index 52230d2504..6cd7a2edda 100644
---- a/app/test/test_distributor.c
-+++ b/app/test/test_distributor.c
+diff --git a/test/test/test_distributor.c b/test/test/test_distributor.c
+index ae7eff5a91..45b4b22b43 100644
+--- a/test/test/test_distributor.c
++++ b/test/test/test_distributor.c
@@ -44 +45 @@
-@@ -341,4 +342,6 @@ handle_work_for_shutdown_test(void *arg)
+@@ -341,11 +342,20 @@ handle_work_for_shutdown_test(void *arg)
@@ -49,3 +50,2 @@
- 	const unsigned int id = __atomic_fetch_add(&worker_idx, 1,
- 			__ATOMIC_RELAXED);
-@@ -346,7 +349,14 @@ handle_work_for_shutdown_test(void *arg)
+ 	const unsigned int id = __sync_fetch_and_add(&worker_idx, 1);
+ 
@@ -57 +57 @@
-+			false, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
++			0, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
@@ -67 +67 @@
-@@ -354,4 +364,12 @@ handle_work_for_shutdown_test(void *arg)
+@@ -353,4 +363,12 @@ handle_work_for_shutdown_test(void *arg)
@@ -74 +74 @@
-+				false, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
++				0, __ATOMIC_ACQ_REL, __ATOMIC_ACQUIRE);
@@ -80 +80 @@
-@@ -360,5 +378,5 @@ handle_work_for_shutdown_test(void *arg)
+@@ -359,5 +377,5 @@ handle_work_for_shutdown_test(void *arg)
@@ -87 +87 @@
-@@ -579,4 +597,5 @@ quit_workers(struct worker_params *wp, struct rte_mempool *p)
+@@ -578,4 +596,5 @@ quit_workers(struct worker_params *wp, struct rte_mempool *p)