Can I get an Acked-by from one of the scheduler maintainers?
-- Steve On Wed, 5 Mar 2025 15:03:54 +0100 Gabriele Monaco <[email protected]> wrote: > Add the following tracepoints: > * sched_entry(bool preempt, ip) > Called while entering __schedule > * sched_exit(bool is_switch, ip) > Called while exiting __schedule > * sched_set_state(task, curr_state, state) > Called when a task changes its state (to and from running) > > These tracepoints are useful to describe the Linux task model and are > adapted from the patches by Daniel Bristot de Oliveira > (https://bristot.me/linux-task-model/). > > Signed-off-by: Gabriele Monaco <[email protected]> > --- > include/linux/rv.h | 2 +- > include/linux/sched.h | 16 ++++++++++++++++ > include/trace/events/sched.h | 13 +++++++++++++ > kernel/sched/core.c | 23 ++++++++++++++++++++++- > tools/verification/rv/include/rv.h | 2 +- > 5 files changed, 53 insertions(+), 3 deletions(-) > > diff --git a/include/linux/rv.h b/include/linux/rv.h > index 8883b41d88ec4..55d458be53a4c 100644 > --- a/include/linux/rv.h > +++ b/include/linux/rv.h > @@ -7,7 +7,7 @@ > #ifndef _LINUX_RV_H > #define _LINUX_RV_H > > -#define MAX_DA_NAME_LEN 24 > +#define MAX_DA_NAME_LEN 32 > > #ifdef CONFIG_RV > /* > diff --git a/include/linux/sched.h b/include/linux/sched.h > index 9632e3318e0d6..45a61a0b97903 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -46,6 +46,7 @@ > #include <linux/rv.h> > #include <linux/livepatch_sched.h> > #include <linux/uidgid_types.h> > +#include <linux/tracepoint-defs.h> > #include <asm/kmap_size.h> > > /* task_struct member predeclarations (sorted alphabetically): */ > @@ -186,6 +187,12 @@ struct user_event_mm; > # define debug_rtlock_wait_restore_state() do { } while (0) > #endif > > +#define trace_set_current_state(state_value) \ > + do { \ > + if (tracepoint_enabled(sched_set_state_tp)) \ > + __trace_set_current_state(state_value); \ > + } while (0) > + > /* > * set_current_state() includes a barrier so that the write of > current->__state > * is correctly serialised wrt the caller's subsequent test of whether to > @@ -226,12 +233,14 @@ struct user_event_mm; > #define __set_current_state(state_value) \ > do { \ > debug_normal_state_change((state_value)); \ > + trace_set_current_state(state_value); \ > WRITE_ONCE(current->__state, (state_value)); \ > } while (0) > > #define set_current_state(state_value) > \ > do { \ > debug_normal_state_change((state_value)); \ > + trace_set_current_state(state_value); \ > smp_store_mb(current->__state, (state_value)); \ > } while (0) > > @@ -247,6 +256,7 @@ struct user_event_mm; > \ > raw_spin_lock_irqsave(¤t->pi_lock, flags); \ > debug_special_state_change((state_value)); \ > + trace_set_current_state(state_value); \ > WRITE_ONCE(current->__state, (state_value)); \ > raw_spin_unlock_irqrestore(¤t->pi_lock, flags); \ > } while (0) > @@ -282,6 +292,7 @@ struct user_event_mm; > raw_spin_lock(¤t->pi_lock); \ > current->saved_state = current->__state; \ > debug_rtlock_wait_set_state(); \ > + trace_set_current_state(TASK_RTLOCK_WAIT); \ > WRITE_ONCE(current->__state, TASK_RTLOCK_WAIT); \ > raw_spin_unlock(¤t->pi_lock); \ > } while (0); > @@ -291,6 +302,7 @@ struct user_event_mm; > lockdep_assert_irqs_disabled(); \ > raw_spin_lock(¤t->pi_lock); \ > debug_rtlock_wait_restore_state(); \ > + trace_set_current_state(current->saved_state); \ > WRITE_ONCE(current->__state, current->saved_state); \ > current->saved_state = TASK_RUNNING; \ > raw_spin_unlock(¤t->pi_lock); \ > @@ -327,6 +339,10 @@ extern void io_schedule_finish(int token); > extern long io_schedule_timeout(long timeout); > extern void io_schedule(void); > > +/* wrapper function to trace from this header file */ > +DECLARE_TRACEPOINT(sched_set_state_tp); > +extern void __trace_set_current_state(int state_value); > + > /** > * struct prev_cputime - snapshot of system and user cputime > * @utime: time spent in user mode > diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h > index 9ea4c404bd4ef..90545125c9031 100644 > --- a/include/trace/events/sched.h > +++ b/include/trace/events/sched.h > @@ -824,6 +824,19 @@ DECLARE_TRACE(sched_compute_energy_tp, > unsigned long max_util, unsigned long busy_time), > TP_ARGS(p, dst_cpu, energy, max_util, busy_time)); > > +DECLARE_TRACE(sched_entry_tp, > + TP_PROTO(bool preempt, unsigned long ip), > + TP_ARGS(preempt, ip)); > + > +DECLARE_TRACE(sched_exit_tp, > + TP_PROTO(bool is_switch, unsigned long ip), > + TP_ARGS(is_switch, ip)); > + > +DECLARE_TRACE_CONDITION(sched_set_state_tp, > + TP_PROTO(struct task_struct *tsk, int state), > + TP_ARGS(tsk, state), > + TP_CONDITION(!!(tsk->__state) != !!state)); > + > #endif /* _TRACE_SCHED_H */ > > /* This part must be outside protection */ > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 67189907214d3..5d36ccf565e94 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -491,6 +491,16 @@ sched_core_dequeue(struct rq *rq, struct task_struct *p, > int flags) { } > > #endif /* CONFIG_SCHED_CORE */ > > +/* need a wrapper since we may need to trace from modules */ > +EXPORT_TRACEPOINT_SYMBOL(sched_set_state_tp); > + > +/* Call via the helper macro trace_set_current_state. */ > +void __trace_set_current_state(int state_value) > +{ > + trace_sched_set_state_tp(current, state_value); > +} > +EXPORT_SYMBOL(__trace_set_current_state); > + > /* > * Serialization rules: > * > @@ -5307,6 +5317,12 @@ asmlinkage __visible void schedule_tail(struct > task_struct *prev) > */ > > finish_task_switch(prev); > + /* > + * This is a special case: the newly created task has just > + * switched the context for the first time. It is returning from > + * schedule for the first time in this path. > + */ > + trace_sched_exit_tp(true, CALLER_ADDR0); > preempt_enable(); > > if (current->set_child_tid) > @@ -6650,12 +6666,15 @@ static void __sched notrace __schedule(int sched_mode) > * as a preemption by schedule_debug() and RCU. > */ > bool preempt = sched_mode > SM_NONE; > + bool is_switch = false; > unsigned long *switch_count; > unsigned long prev_state; > struct rq_flags rf; > struct rq *rq; > int cpu; > > + trace_sched_entry_tp(preempt, CALLER_ADDR0); > + > cpu = smp_processor_id(); > rq = cpu_rq(cpu); > prev = rq->curr; > @@ -6723,7 +6742,8 @@ static void __sched notrace __schedule(int sched_mode) > rq->last_seen_need_resched_ns = 0; > #endif > > - if (likely(prev != next)) { > + is_switch = prev != next; > + if (likely(is_switch)) { > rq->nr_switches++; > /* > * RCU users of rcu_dereference(rq->curr) may not see > @@ -6768,6 +6788,7 @@ static void __sched notrace __schedule(int sched_mode) > __balance_callbacks(rq); > raw_spin_rq_unlock_irq(rq); > } > + trace_sched_exit_tp(is_switch, CALLER_ADDR0); > } > > void __noreturn do_task_dead(void) > diff --git a/tools/verification/rv/include/rv.h > b/tools/verification/rv/include/rv.h > index 770fd6da36107..0cab1037a98f7 100644 > --- a/tools/verification/rv/include/rv.h > +++ b/tools/verification/rv/include/rv.h > @@ -1,7 +1,7 @@ > // SPDX-License-Identifier: GPL-2.0 > > #define MAX_DESCRIPTION 1024 > -#define MAX_DA_NAME_LEN 24 > +#define MAX_DA_NAME_LEN 32 > > struct monitor { > char name[MAX_DA_NAME_LEN];
