If a timer's callback function calls rte_timer_reset_sync() or rte_timer_stop_sync() on another timer that is in the RUNNING state and owned by the current lcore, the *_sync() calls will loop indefinitely. Relatedly, if a timer's callback function calls *_sync() on another timer that is in the RUNNING state and is owned by a different lcore, but a timer callback function runs on that different lcore and calls *_sync() on a timer that is in the RUNNING state and owned by the current lcore, the two lcores will loop indefinitely. Add a note in the rte_timer_stop_sync and rte_timer_reset_sync documentation that indicates that these APIs should not be used inside timer callback functions in order to avoid the hangs described above, and suggests an alternative. Bugzilla ID: 491 Cc: stable@dpdk.org Signed-off-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com> --- lib/librte_timer/rte_timer.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/lib/librte_timer/rte_timer.h b/lib/librte_timer/rte_timer.h index c6b3d45..d7c3e03 100644 --- a/lib/librte_timer/rte_timer.h +++ b/lib/librte_timer/rte_timer.h @@ -274,6 +274,12 @@ int rte_timer_reset(struct rte_timer *tim, uint64_t ticks, * The callback function of the timer. * @param arg * The user argument of the callback function. + * + * @note + * This API should not be called inside a timer's callback function to + * reset another timer; doing so could hang in certain scenarios. Instead, + * the rte_timer_reset() API can be called directly and its return code + * can be checked for success or failure. */ void rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks, @@ -313,6 +319,12 @@ int rte_timer_stop(struct rte_timer *tim); * * @param tim * The timer handle. + * + * @note + * This API should not be called inside a timer's callback function to + * stop another timer; doing so could hang in certain scenarios. Instead, the + * rte_timer_stop() API can be called directly and its return code can + * be checked for success or failure. */ void rte_timer_stop_sync(struct rte_timer *tim); -- 2.6.4
If a timer's callback function calls rte_timer_reset_sync() or rte_timer_stop_sync() on another timer that is in the RUNNING state and owned by the current lcore, the *_sync() calls will loop indefinitely. Relatedly, if a timer's callback function calls *_sync() on another timer that is in the RUNNING state and is owned by a different lcore, but a timer callback function runs on that different lcore and calls *_sync() on a timer that is in the RUNNING state and owned by the current lcore, the two lcores will loop indefinitely. Add a note in the rte_timer_stop_sync and rte_timer_reset_sync documentation that indicates that these APIs should not be used inside timer callback functions in order to avoid the hangs described above, and suggests an alternative. Bugzilla ID: 491 Cc: stable@dpdk.org Signed-off-by: Erik Gabriel Carrillo <erik.g.carrillo@intel.com> --- lib/librte_timer/rte_timer.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/lib/librte_timer/rte_timer.h b/lib/librte_timer/rte_timer.h index c6b3d45..d7c3e03 100644 --- a/lib/librte_timer/rte_timer.h +++ b/lib/librte_timer/rte_timer.h @@ -274,6 +274,12 @@ int rte_timer_reset(struct rte_timer *tim, uint64_t ticks, * The callback function of the timer. * @param arg * The user argument of the callback function. + * + * @note + * This API should not be called inside a timer's callback function to + * reset another timer; doing so could hang in certain scenarios. Instead, + * the rte_timer_reset() API can be called directly and its return code + * can be checked for success or failure. */ void rte_timer_reset_sync(struct rte_timer *tim, uint64_t ticks, @@ -313,6 +319,12 @@ int rte_timer_stop(struct rte_timer *tim); * * @param tim * The timer handle. + * + * @note + * This API should not be called inside a timer's callback function to + * stop another timer; doing so could hang in certain scenarios. Instead, the + * rte_timer_stop() API can be called directly and its return code can + * be checked for success or failure. */ void rte_timer_stop_sync(struct rte_timer *tim); -- 2.6.4