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-rw-r--r--include/linux/rv.h3
-rw-r--r--include/rv/da_monitor.h107
-rw-r--r--kernel/trace/rv/Kconfig5
-rw-r--r--kernel/trace/rv/rv_trace.h24
4 files changed, 85 insertions, 54 deletions
diff --git a/include/linux/rv.h b/include/linux/rv.h
index 80731242fe60..14410a42faef 100644
--- a/include/linux/rv.h
+++ b/include/linux/rv.h
@@ -10,7 +10,8 @@
#include <linux/types.h>
#include <linux/list.h>
-#define MAX_DA_NAME_LEN 32
+#define MAX_DA_NAME_LEN 32
+#define MAX_DA_RETRY_RACING_EVENTS 3
#ifdef CONFIG_RV
#include <linux/bitops.h>
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index ed3c34fe18d6..17fa4f6e5ea6 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -55,23 +55,6 @@ static inline void da_monitor_reset_##name(struct da_monitor *da_mon) \
} \
\
/* \
- * da_monitor_curr_state_##name - return the current state \
- */ \
-static inline type da_monitor_curr_state_##name(struct da_monitor *da_mon) \
-{ \
- return da_mon->curr_state; \
-} \
- \
-/* \
- * da_monitor_set_state_##name - set the new current state \
- */ \
-static inline void \
-da_monitor_set_state_##name(struct da_monitor *da_mon, enum states_##name state) \
-{ \
- da_mon->curr_state = state; \
-} \
- \
-/* \
* da_monitor_start_##name - start monitoring \
* \
* The monitor will ignore all events until monitoring is set to true. This \
@@ -127,63 +110,81 @@ static inline bool da_monitor_handling_event_##name(struct da_monitor *da_mon)
* Event handler for implicit monitors. Implicit monitor is the one which the
* handler does not need to specify which da_monitor to manipulate. Examples
* of implicit monitor are the per_cpu or the global ones.
+ *
+ * Retry in case there is a race between getting and setting the next state,
+ * warn and reset the monitor if it runs out of retries. The monitor should be
+ * able to handle various orders.
*/
#define DECLARE_DA_MON_MODEL_HANDLER_IMPLICIT(name, type) \
\
static inline bool \
da_event_##name(struct da_monitor *da_mon, enum events_##name event) \
{ \
- type curr_state = da_monitor_curr_state_##name(da_mon); \
- type next_state = model_get_next_state_##name(curr_state, event); \
- \
- if (next_state != INVALID_STATE) { \
- da_monitor_set_state_##name(da_mon, next_state); \
- \
- trace_event_##name(model_get_state_name_##name(curr_state), \
- model_get_event_name_##name(event), \
- model_get_state_name_##name(next_state), \
- model_is_final_state_##name(next_state)); \
- \
- return true; \
+ enum states_##name curr_state, next_state; \
+ \
+ curr_state = READ_ONCE(da_mon->curr_state); \
+ for (int i = 0; i < MAX_DA_RETRY_RACING_EVENTS; i++) { \
+ next_state = model_get_next_state_##name(curr_state, event); \
+ if (next_state == INVALID_STATE) { \
+ cond_react_##name(curr_state, event); \
+ trace_error_##name(model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event)); \
+ return false; \
+ } \
+ if (likely(try_cmpxchg(&da_mon->curr_state, &curr_state, next_state))) { \
+ trace_event_##name(model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(next_state), \
+ model_is_final_state_##name(next_state)); \
+ return true; \
+ } \
} \
\
- cond_react_##name(curr_state, event); \
- \
- trace_error_##name(model_get_state_name_##name(curr_state), \
- model_get_event_name_##name(event)); \
- \
+ trace_rv_retries_error(#name, model_get_event_name_##name(event)); \
+ pr_warn("rv: " __stringify(MAX_DA_RETRY_RACING_EVENTS) \
+ " retries reached for event %s, resetting monitor %s", \
+ model_get_event_name_##name(event), #name); \
return false; \
} \
/*
* Event handler for per_task monitors.
+ *
+ * Retry in case there is a race between getting and setting the next state,
+ * warn and reset the monitor if it runs out of retries. The monitor should be
+ * able to handle various orders.
*/
#define DECLARE_DA_MON_MODEL_HANDLER_PER_TASK(name, type) \
\
static inline bool da_event_##name(struct da_monitor *da_mon, struct task_struct *tsk, \
enum events_##name event) \
{ \
- type curr_state = da_monitor_curr_state_##name(da_mon); \
- type next_state = model_get_next_state_##name(curr_state, event); \
- \
- if (next_state != INVALID_STATE) { \
- da_monitor_set_state_##name(da_mon, next_state); \
- \
- trace_event_##name(tsk->pid, \
- model_get_state_name_##name(curr_state), \
- model_get_event_name_##name(event), \
- model_get_state_name_##name(next_state), \
- model_is_final_state_##name(next_state)); \
- \
- return true; \
+ enum states_##name curr_state, next_state; \
+ \
+ curr_state = READ_ONCE(da_mon->curr_state); \
+ for (int i = 0; i < MAX_DA_RETRY_RACING_EVENTS; i++) { \
+ next_state = model_get_next_state_##name(curr_state, event); \
+ if (next_state == INVALID_STATE) { \
+ cond_react_##name(curr_state, event); \
+ trace_error_##name(tsk->pid, \
+ model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event)); \
+ return false; \
+ } \
+ if (likely(try_cmpxchg(&da_mon->curr_state, &curr_state, next_state))) { \
+ trace_event_##name(tsk->pid, \
+ model_get_state_name_##name(curr_state), \
+ model_get_event_name_##name(event), \
+ model_get_state_name_##name(next_state), \
+ model_is_final_state_##name(next_state)); \
+ return true; \
+ } \
} \
\
- cond_react_##name(curr_state, event); \
- \
- trace_error_##name(tsk->pid, \
- model_get_state_name_##name(curr_state), \
- model_get_event_name_##name(event)); \
- \
+ trace_rv_retries_error(#name, model_get_event_name_##name(event)); \
+ pr_warn("rv: " __stringify(MAX_DA_RETRY_RACING_EVENTS) \
+ " retries reached for event %s, resetting monitor %s", \
+ model_get_event_name_##name(event), #name); \
return false; \
}
diff --git a/kernel/trace/rv/Kconfig b/kernel/trace/rv/Kconfig
index 26017378f79b..34164eb4ec91 100644
--- a/kernel/trace/rv/Kconfig
+++ b/kernel/trace/rv/Kconfig
@@ -3,12 +3,17 @@
config RV_MON_EVENTS
bool
+config RV_MON_MAINTENANCE_EVENTS
+ bool
+
config DA_MON_EVENTS_IMPLICIT
select RV_MON_EVENTS
+ select RV_MON_MAINTENANCE_EVENTS
bool
config DA_MON_EVENTS_ID
select RV_MON_EVENTS
+ select RV_MON_MAINTENANCE_EVENTS
bool
config LTL_MON_EVENTS_ID
diff --git a/kernel/trace/rv/rv_trace.h b/kernel/trace/rv/rv_trace.h
index d38e0d3abdfd..3af46cd185b3 100644
--- a/kernel/trace/rv/rv_trace.h
+++ b/kernel/trace/rv/rv_trace.h
@@ -176,6 +176,30 @@ DECLARE_EVENT_CLASS(error_ltl_monitor_id,
#include <monitors/sleep/sleep_trace.h>
// Add new monitors based on CONFIG_LTL_MON_EVENTS_ID here
#endif /* CONFIG_LTL_MON_EVENTS_ID */
+
+#ifdef CONFIG_RV_MON_MAINTENANCE_EVENTS
+/* Tracepoint useful for monitors development, currenly only used in DA */
+TRACE_EVENT(rv_retries_error,
+
+ TP_PROTO(char *name, char *event),
+
+ TP_ARGS(name, event),
+
+ TP_STRUCT__entry(
+ __string( name, name )
+ __string( event, event )
+ ),
+
+ TP_fast_assign(
+ __assign_str(name);
+ __assign_str(event);
+ ),
+
+ TP_printk(__stringify(MAX_DA_RETRY_RACING_EVENTS)
+ " retries reached for event %s, resetting monitor %s",
+ __get_str(event), __get_str(name))
+);
+#endif /* CONFIG_RV_MON_MAINTENANCE_EVENTS */
#endif /* _TRACE_RV_H */
/* This part must be outside protection */
generated by cgit (git 2.34.1) at 2025-09-14 17:28:31 +0000