[PATCH] service: debug and fix lingering might_be_active() result

[PATCH] service: debug and fix lingering might_be_active() result

[Harry van Haaren]

This commit fixes an issue where calling rte_service_lcore_stop()
would result in a service's "active on lcore" status becoming stale.

The stale status would result in rte_service_may_be_active() always
returning "1", indiciating that the service is not certainly stopped.

This is fixed by ensuring the "active on lcore" status of each service
is set to 0 when an lcore is stopped.

Fixes: e30dd31847d2 ("service: add mechanism for quiescing")
Fixes: 8929de043eb4 ("service: retrieve lcore active state")

Reported-by: S. V. Naga Harish <s.v.naga.harish.k@intel.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
---
 lib/eal/common/rte_service.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/eal/common/rte_service.c b/lib/eal/common/rte_service.c
index ef31b1f63c..d2b7275ac0 100644
--- a/lib/eal/common/rte_service.c
+++ b/lib/eal/common/rte_service.c
@@ -758,7 +758,9 @@ rte_service_lcore_stop(uint32_t lcore)
 		return -EALREADY;
 
 	uint32_t i;
-	uint64_t service_mask = lcore_states[lcore].service_mask;
+	struct core_state *cs = &lcore_states[lcore];
+	uint64_t service_mask = cs->service_mask;
+
 	for (i = 0; i < RTE_SERVICE_NUM_MAX; i++) {
 		int32_t enabled = service_mask & (UINT64_C(1) << i);
 		int32_t service_running = rte_service_runstate_get(i);
@@ -766,6 +768,11 @@ rte_service_lcore_stop(uint32_t lcore)
 			__atomic_load_n(&rte_services[i].num_mapped_cores,
 				__ATOMIC_RELAXED));
 
+		/* Switch off this core for all services, to ensure that future
+		 * calls to may_be_active() know this core is switched off.
+		 */
+		cs->service_active_on_lcore[i] = 0;
+
 		/* if the core is mapped, and the service is running, and this
 		 * is the only core that is mapped, the service would cease to
 		 * run if this core stopped, so fail instead.
-- 
2.32.0

Re: [PATCH] service: debug and fix lingering might_be_active() result

[Thomas Monjalon]

05/07/2022 15:32, Harry van Haaren:
> This commit fixes an issue where calling rte_service_lcore_stop()
> would result in a service's "active on lcore" status becoming stale.
> 
> The stale status would result in rte_service_may_be_active() always
> returning "1", indiciating that the service is not certainly stopped.
> 
> This is fixed by ensuring the "active on lcore" status of each service
> is set to 0 when an lcore is stopped.
> 
> Fixes: e30dd31847d2 ("service: add mechanism for quiescing")
> Fixes: 8929de043eb4 ("service: retrieve lcore active state")
> 
> Reported-by: S. V. Naga Harish <s.v.naga.harish.k@intel.com>
> Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>

Applied, thanks.