* [dpdk-stable] [PATCH 1/1] timer: add limitation note for sync stop and reset [not found] <1599662330-44663-1-git-send-email-erik.g.carrillo@intel.com> @ 2020-09-09 14:38 ` Erik Gabriel Carrillo 0 siblings, 0 replies; 2+ messages in thread From: Erik Gabriel Carrillo @ 2020-09-09 14:38 UTC (permalink / raw) To: erik.g.carrillo; +Cc: stable 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 ^ permalink raw reply [flat|nested] 2+ messages in thread
[parent not found: <1599662474-44882-1-git-send-email-erik.g.carrillo@intel.com>]
* [dpdk-stable] [PATCH 1/1] timer: add limitation note for sync stop and reset [not found] <1599662474-44882-1-git-send-email-erik.g.carrillo@intel.com> @ 2020-09-09 14:41 ` Erik Gabriel Carrillo 0 siblings, 0 replies; 2+ messages in thread From: Erik Gabriel Carrillo @ 2020-09-09 14:41 UTC (permalink / raw) To: dev; +Cc: stable 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 ^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-09-09 14:38 ` [dpdk-stable] [PATCH 1/1] timer: add limitation note for sync stop and reset Erik Gabriel Carrillo
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2020-09-09 14:41 ` Erik Gabriel Carrillo
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