151 lines
3.8 KiB
C
151 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/ftrace.h>
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#include <linux/tracepoint.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/rv.h>
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#include <rv/instrumentation.h>
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#define MODULE_NAME "stall"
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#include <trace/events/sched.h>
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#include <rv_trace.h>
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#define RV_MON_TYPE RV_MON_PER_TASK
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#define HA_TIMER_TYPE HA_TIMER_WHEEL
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#include "stall.h"
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#include <rv/ha_monitor.h>
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static u64 threshold_jiffies = 1000;
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module_param(threshold_jiffies, ullong, 0644);
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static u64 ha_get_env(struct ha_monitor *ha_mon, enum envs_stall env, u64 time_ns)
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{
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if (env == clk_stall)
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return ha_get_clk_jiffy(ha_mon, env);
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return ENV_INVALID_VALUE;
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}
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static void ha_reset_env(struct ha_monitor *ha_mon, enum envs_stall env, u64 time_ns)
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{
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if (env == clk_stall)
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ha_reset_clk_jiffy(ha_mon, env);
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}
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static inline bool ha_verify_invariants(struct ha_monitor *ha_mon,
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enum states curr_state, enum events event,
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enum states next_state, u64 time_ns)
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{
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if (curr_state == enqueued_stall)
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return ha_check_invariant_jiffy(ha_mon, clk_stall, time_ns);
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return true;
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}
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static inline bool ha_verify_guards(struct ha_monitor *ha_mon,
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enum states curr_state, enum events event,
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enum states next_state, u64 time_ns)
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{
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bool res = true;
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if (curr_state == dequeued_stall && event == sched_wakeup_stall)
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ha_reset_env(ha_mon, clk_stall, time_ns);
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else if (curr_state == running_stall && event == sched_switch_preempt_stall)
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ha_reset_env(ha_mon, clk_stall, time_ns);
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return res;
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}
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static inline void ha_setup_invariants(struct ha_monitor *ha_mon,
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enum states curr_state, enum events event,
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enum states next_state, u64 time_ns)
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{
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if (next_state == curr_state)
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return;
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if (next_state == enqueued_stall)
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ha_start_timer_jiffy(ha_mon, clk_stall, threshold_jiffies, time_ns);
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else if (curr_state == enqueued_stall)
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ha_cancel_timer(ha_mon);
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}
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static bool ha_verify_constraint(struct ha_monitor *ha_mon,
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enum states curr_state, enum events event,
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enum states next_state, u64 time_ns)
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{
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if (!ha_verify_invariants(ha_mon, curr_state, event, next_state, time_ns))
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return false;
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if (!ha_verify_guards(ha_mon, curr_state, event, next_state, time_ns))
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return false;
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ha_setup_invariants(ha_mon, curr_state, event, next_state, time_ns);
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return true;
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}
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static void handle_sched_switch(void *data, bool preempt,
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struct task_struct *prev,
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struct task_struct *next,
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unsigned int prev_state)
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{
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if (!preempt && prev_state != TASK_RUNNING)
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da_handle_start_event(prev, sched_switch_wait_stall);
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else
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da_handle_event(prev, sched_switch_preempt_stall);
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da_handle_event(next, sched_switch_in_stall);
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}
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static void handle_sched_wakeup(void *data, struct task_struct *p)
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{
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da_handle_event(p, sched_wakeup_stall);
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}
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static int enable_stall(void)
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{
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int retval;
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retval = ha_monitor_init();
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if (retval)
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return retval;
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rv_attach_trace_probe("stall", sched_switch, handle_sched_switch);
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rv_attach_trace_probe("stall", sched_wakeup, handle_sched_wakeup);
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return 0;
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}
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static void disable_stall(void)
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{
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rv_this.enabled = 0;
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rv_detach_trace_probe("stall", sched_switch, handle_sched_switch);
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rv_detach_trace_probe("stall", sched_wakeup, handle_sched_wakeup);
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ha_monitor_destroy();
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}
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static struct rv_monitor rv_this = {
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.name = "stall",
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.description = "identify tasks stalled for longer than a threshold.",
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.enable = enable_stall,
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.disable = disable_stall,
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.reset = da_monitor_reset_all,
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.enabled = 0,
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};
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static int __init register_stall(void)
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{
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return rv_register_monitor(&rv_this, NULL);
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}
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static void __exit unregister_stall(void)
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{
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rv_unregister_monitor(&rv_this);
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}
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module_init(register_stall);
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module_exit(unregister_stall);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Gabriele Monaco <gmonaco@redhat.com>");
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MODULE_DESCRIPTION("stall: identify tasks stalled for longer than a threshold.");
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