diff options
Diffstat (limited to 'kernel/trace/trace_sched_wakeup.c')
| -rw-r--r-- | kernel/trace/trace_sched_wakeup.c | 489 |
1 files changed, 418 insertions, 71 deletions
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c index 0271742abb8..19bd8928ce9 100644 --- a/kernel/trace/trace_sched_wakeup.c +++ b/kernel/trace/trace_sched_wakeup.c @@ -7,7 +7,7 @@ * Based on code from the latency_tracer, that is: * * Copyright (C) 2004-2006 Ingo Molnar - * Copyright (C) 2004 William Lee Irwin III + * Copyright (C) 2004 Nadia Yvette Chambers */ #include <linux/module.h> #include <linux/fs.h> @@ -15,8 +15,9 @@ #include <linux/kallsyms.h> #include <linux/uaccess.h> #include <linux/ftrace.h> +#include <linux/sched/rt.h> +#include <linux/sched/deadline.h> #include <trace/events/sched.h> - #include "trace.h" static struct trace_array *wakeup_trace; @@ -27,78 +28,336 @@ static int wakeup_cpu; static int wakeup_current_cpu; static unsigned wakeup_prio = -1; static int wakeup_rt; +static int wakeup_dl; +static int tracing_dl = 0; static arch_spinlock_t wakeup_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; +static void wakeup_reset(struct trace_array *tr); static void __wakeup_reset(struct trace_array *tr); +static int wakeup_graph_entry(struct ftrace_graph_ent *trace); +static void wakeup_graph_return(struct ftrace_graph_ret *trace); + +static int save_flags; +static bool function_enabled; + +#define TRACE_DISPLAY_GRAPH 1 + +static struct tracer_opt trace_opts[] = { +#ifdef CONFIG_FUNCTION_GRAPH_TRACER + /* display latency trace as call graph */ + { TRACER_OPT(display-graph, TRACE_DISPLAY_GRAPH) }, +#endif + { } /* Empty entry */ +}; -static int save_lat_flag; +static struct tracer_flags tracer_flags = { + .val = 0, + .opts = trace_opts, +}; + +#define is_graph() (tracer_flags.val & TRACE_DISPLAY_GRAPH) #ifdef CONFIG_FUNCTION_TRACER + /* - * irqsoff uses its own tracer function to keep the overhead down: + * Prologue for the wakeup function tracers. + * + * Returns 1 if it is OK to continue, and preemption + * is disabled and data->disabled is incremented. + * 0 if the trace is to be ignored, and preemption + * is not disabled and data->disabled is + * kept the same. + * + * Note, this function is also used outside this ifdef but + * inside the #ifdef of the function graph tracer below. + * This is OK, since the function graph tracer is + * dependent on the function tracer. */ -static void -wakeup_tracer_call(unsigned long ip, unsigned long parent_ip) +static int +func_prolog_preempt_disable(struct trace_array *tr, + struct trace_array_cpu **data, + int *pc) { - struct trace_array *tr = wakeup_trace; - struct trace_array_cpu *data; - unsigned long flags; long disabled; - int resched; int cpu; - int pc; if (likely(!wakeup_task)) - return; + return 0; - pc = preempt_count(); - resched = ftrace_preempt_disable(); + *pc = preempt_count(); + preempt_disable_notrace(); cpu = raw_smp_processor_id(); if (cpu != wakeup_current_cpu) goto out_enable; - data = tr->data[cpu]; - disabled = atomic_inc_return(&data->disabled); + *data = per_cpu_ptr(tr->trace_buffer.data, cpu); + disabled = atomic_inc_return(&(*data)->disabled); if (unlikely(disabled != 1)) goto out; - local_irq_save(flags); + return 1; - trace_function(tr, ip, parent_ip, flags, pc); +out: + atomic_dec(&(*data)->disabled); + +out_enable: + preempt_enable_notrace(); + return 0; +} + +/* + * wakeup uses its own tracer function to keep the overhead down: + */ +static void +wakeup_tracer_call(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct pt_regs *pt_regs) +{ + struct trace_array *tr = wakeup_trace; + struct trace_array_cpu *data; + unsigned long flags; + int pc; + if (!func_prolog_preempt_disable(tr, &data, &pc)) + return; + + local_irq_save(flags); + trace_function(tr, ip, parent_ip, flags, pc); local_irq_restore(flags); - out: atomic_dec(&data->disabled); - out_enable: - ftrace_preempt_enable(resched); + preempt_enable_notrace(); } +#endif /* CONFIG_FUNCTION_TRACER */ -static struct ftrace_ops trace_ops __read_mostly = +static int register_wakeup_function(struct trace_array *tr, int graph, int set) { - .func = wakeup_tracer_call, -}; + int ret; + + /* 'set' is set if TRACE_ITER_FUNCTION is about to be set */ + if (function_enabled || (!set && !(trace_flags & TRACE_ITER_FUNCTION))) + return 0; + + if (graph) + ret = register_ftrace_graph(&wakeup_graph_return, + &wakeup_graph_entry); + else + ret = register_ftrace_function(tr->ops); + + if (!ret) + function_enabled = true; + + return ret; +} + +static void unregister_wakeup_function(struct trace_array *tr, int graph) +{ + if (!function_enabled) + return; + + if (graph) + unregister_ftrace_graph(); + else + unregister_ftrace_function(tr->ops); + + function_enabled = false; +} + +static void wakeup_function_set(struct trace_array *tr, int set) +{ + if (set) + register_wakeup_function(tr, is_graph(), 1); + else + unregister_wakeup_function(tr, is_graph()); +} + +static int wakeup_flag_changed(struct trace_array *tr, u32 mask, int set) +{ + struct tracer *tracer = tr->current_trace; + + if (mask & TRACE_ITER_FUNCTION) + wakeup_function_set(tr, set); + + return trace_keep_overwrite(tracer, mask, set); +} + +static int start_func_tracer(struct trace_array *tr, int graph) +{ + int ret; + + ret = register_wakeup_function(tr, graph, 0); + + if (!ret && tracing_is_enabled()) + tracer_enabled = 1; + else + tracer_enabled = 0; + + return ret; +} + +static void stop_func_tracer(struct trace_array *tr, int graph) +{ + tracer_enabled = 0; + + unregister_wakeup_function(tr, graph); +} + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +static int +wakeup_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) +{ + + if (!(bit & TRACE_DISPLAY_GRAPH)) + return -EINVAL; + + if (!(is_graph() ^ set)) + return 0; + + stop_func_tracer(tr, !set); + + wakeup_reset(wakeup_trace); + tr->max_latency = 0; + + return start_func_tracer(tr, set); +} + +static int wakeup_graph_entry(struct ftrace_graph_ent *trace) +{ + struct trace_array *tr = wakeup_trace; + struct trace_array_cpu *data; + unsigned long flags; + int pc, ret = 0; + + if (!func_prolog_preempt_disable(tr, &data, &pc)) + return 0; + + local_save_flags(flags); + ret = __trace_graph_entry(tr, trace, flags, pc); + atomic_dec(&data->disabled); + preempt_enable_notrace(); + + return ret; +} + +static void wakeup_graph_return(struct ftrace_graph_ret *trace) +{ + struct trace_array *tr = wakeup_trace; + struct trace_array_cpu *data; + unsigned long flags; + int pc; + + if (!func_prolog_preempt_disable(tr, &data, &pc)) + return; + + local_save_flags(flags); + __trace_graph_return(tr, trace, flags, pc); + atomic_dec(&data->disabled); + + preempt_enable_notrace(); + return; +} + +static void wakeup_trace_open(struct trace_iterator *iter) +{ + if (is_graph()) + graph_trace_open(iter); +} + +static void wakeup_trace_close(struct trace_iterator *iter) +{ + if (iter->private) + graph_trace_close(iter); +} + +#define GRAPH_TRACER_FLAGS (TRACE_GRAPH_PRINT_PROC | \ + TRACE_GRAPH_PRINT_ABS_TIME | \ + TRACE_GRAPH_PRINT_DURATION) + +static enum print_line_t wakeup_print_line(struct trace_iterator *iter) +{ + /* + * In graph mode call the graph tracer output function, + * otherwise go with the TRACE_FN event handler + */ + if (is_graph()) + return print_graph_function_flags(iter, GRAPH_TRACER_FLAGS); + + return TRACE_TYPE_UNHANDLED; +} + +static void wakeup_print_header(struct seq_file *s) +{ + if (is_graph()) + print_graph_headers_flags(s, GRAPH_TRACER_FLAGS); + else + trace_default_header(s); +} + +static void +__trace_function(struct trace_array *tr, + unsigned long ip, unsigned long parent_ip, + unsigned long flags, int pc) +{ + if (is_graph()) + trace_graph_function(tr, ip, parent_ip, flags, pc); + else + trace_function(tr, ip, parent_ip, flags, pc); +} +#else +#define __trace_function trace_function + +static int +wakeup_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set) +{ + return -EINVAL; +} + +static int wakeup_graph_entry(struct ftrace_graph_ent *trace) +{ + return -1; +} + +static enum print_line_t wakeup_print_line(struct trace_iterator *iter) +{ + return TRACE_TYPE_UNHANDLED; +} + +static void wakeup_graph_return(struct ftrace_graph_ret *trace) { } +static void wakeup_trace_open(struct trace_iterator *iter) { } +static void wakeup_trace_close(struct trace_iterator *iter) { } + +#ifdef CONFIG_FUNCTION_TRACER +static void wakeup_print_header(struct seq_file *s) +{ + trace_default_header(s); +} +#else +static void wakeup_print_header(struct seq_file *s) +{ + trace_latency_header(s); +} #endif /* CONFIG_FUNCTION_TRACER */ +#endif /* CONFIG_FUNCTION_GRAPH_TRACER */ /* * Should this new latency be reported/recorded? */ -static int report_latency(cycle_t delta) +static int report_latency(struct trace_array *tr, cycle_t delta) { if (tracing_thresh) { if (delta < tracing_thresh) return 0; } else { - if (delta <= tracing_max_latency) + if (delta <= tr->max_latency) return 0; } return 1; } -static void probe_wakeup_migrate_task(struct task_struct *task, int cpu) +static void +probe_wakeup_migrate_task(void *ignore, struct task_struct *task, int cpu) { if (task != wakeup_task) return; @@ -107,8 +366,8 @@ static void probe_wakeup_migrate_task(struct task_struct *task, int cpu) } static void notrace -probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev, - struct task_struct *next) +probe_wakeup_sched_switch(void *ignore, + struct task_struct *prev, struct task_struct *next) { struct trace_array_cpu *data; cycle_t T0, T1, delta; @@ -138,7 +397,7 @@ probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev, /* disable local data, not wakeup_cpu data */ cpu = raw_smp_processor_id(); - disabled = atomic_inc_return(&wakeup_trace->data[cpu]->disabled); + disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled); if (likely(disabled != 1)) goto out; @@ -150,20 +409,20 @@ probe_wakeup_sched_switch(struct rq *rq, struct task_struct *prev, goto out_unlock; /* The task we are waiting for is waking up */ - data = wakeup_trace->data[wakeup_cpu]; + data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu); - trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc); + __trace_function(wakeup_trace, CALLER_ADDR0, CALLER_ADDR1, flags, pc); tracing_sched_switch_trace(wakeup_trace, prev, next, flags, pc); T0 = data->preempt_timestamp; T1 = ftrace_now(cpu); delta = T1-T0; - if (!report_latency(delta)) + if (!report_latency(wakeup_trace, delta)) goto out_unlock; if (likely(!is_tracing_stopped())) { - tracing_max_latency = delta; + wakeup_trace->max_latency = delta; update_max_tr(wakeup_trace, wakeup_task, wakeup_cpu); } @@ -172,13 +431,14 @@ out_unlock: arch_spin_unlock(&wakeup_lock); local_irq_restore(flags); out: - atomic_dec(&wakeup_trace->data[cpu]->disabled); + atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled); } static void __wakeup_reset(struct trace_array *tr) { wakeup_cpu = -1; wakeup_prio = -1; + tracing_dl = 0; if (wakeup_task) put_task_struct(wakeup_task); @@ -190,7 +450,7 @@ static void wakeup_reset(struct trace_array *tr) { unsigned long flags; - tracing_reset_online_cpus(tr); + tracing_reset_online_cpus(&tr->trace_buffer); local_irq_save(flags); arch_spin_lock(&wakeup_lock); @@ -200,7 +460,7 @@ static void wakeup_reset(struct trace_array *tr) } static void -probe_wakeup(struct rq *rq, struct task_struct *p, int success) +probe_wakeup(void *ignore, struct task_struct *p, int success) { struct trace_array_cpu *data; int cpu = smp_processor_id(); @@ -214,13 +474,21 @@ probe_wakeup(struct rq *rq, struct task_struct *p, int success) tracing_record_cmdline(p); tracing_record_cmdline(current); - if ((wakeup_rt && !rt_task(p)) || - p->prio >= wakeup_prio || - p->prio >= current->prio) + /* + * Semantic is like this: + * - wakeup tracer handles all tasks in the system, independently + * from their scheduling class; + * - wakeup_rt tracer handles tasks belonging to sched_dl and + * sched_rt class; + * - wakeup_dl handles tasks belonging to sched_dl class only. + */ + if (tracing_dl || (wakeup_dl && !dl_task(p)) || + (wakeup_rt && !dl_task(p) && !rt_task(p)) || + (!dl_task(p) && (p->prio >= wakeup_prio || p->prio >= current->prio))) return; pc = preempt_count(); - disabled = atomic_inc_return(&wakeup_trace->data[cpu]->disabled); + disabled = atomic_inc_return(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled); if (unlikely(disabled != 1)) goto out; @@ -228,7 +496,8 @@ probe_wakeup(struct rq *rq, struct task_struct *p, int success) arch_spin_lock(&wakeup_lock); /* check for races. */ - if (!tracer_enabled || p->prio >= wakeup_prio) + if (!tracer_enabled || tracing_dl || + (!dl_task(p) && p->prio >= wakeup_prio)) goto out_locked; /* reset the trace */ @@ -238,12 +507,21 @@ probe_wakeup(struct rq *rq, struct task_struct *p, int success) wakeup_current_cpu = wakeup_cpu; wakeup_prio = p->prio; + /* + * Once you start tracing a -deadline task, don't bother tracing + * another task until the first one wakes up. + */ + if (dl_task(p)) + tracing_dl = 1; + else + tracing_dl = 0; + wakeup_task = p; get_task_struct(wakeup_task); local_save_flags(flags); - data = wakeup_trace->data[wakeup_cpu]; + data = per_cpu_ptr(wakeup_trace->trace_buffer.data, wakeup_cpu); data->preempt_timestamp = ftrace_now(cpu); tracing_sched_wakeup_trace(wakeup_trace, p, current, flags, pc); @@ -252,40 +530,40 @@ probe_wakeup(struct rq *rq, struct task_struct *p, int success) * is not called by an assembly function (where as schedule is) * it should be safe to use it here. */ - trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc); + __trace_function(wakeup_trace, CALLER_ADDR1, CALLER_ADDR2, flags, pc); out_locked: arch_spin_unlock(&wakeup_lock); out: - atomic_dec(&wakeup_trace->data[cpu]->disabled); + atomic_dec(&per_cpu_ptr(wakeup_trace->trace_buffer.data, cpu)->disabled); } static void start_wakeup_tracer(struct trace_array *tr) { int ret; - ret = register_trace_sched_wakeup(probe_wakeup); + ret = register_trace_sched_wakeup(probe_wakeup, NULL); if (ret) { pr_info("wakeup trace: Couldn't activate tracepoint" " probe to kernel_sched_wakeup\n"); return; } - ret = register_trace_sched_wakeup_new(probe_wakeup); + ret = register_trace_sched_wakeup_new(probe_wakeup, NULL); if (ret) { pr_info("wakeup trace: Couldn't activate tracepoint" " probe to kernel_sched_wakeup_new\n"); goto fail_deprobe; } - ret = register_trace_sched_switch(probe_wakeup_sched_switch); + ret = register_trace_sched_switch(probe_wakeup_sched_switch, NULL); if (ret) { pr_info("sched trace: Couldn't activate tracepoint" " probe to kernel_sched_switch\n"); goto fail_deprobe_wake_new; } - ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task); + ret = register_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL); if (ret) { pr_info("wakeup trace: Couldn't activate tracepoint" " probe to kernel_sched_migrate_task\n"); @@ -303,61 +581,88 @@ static void start_wakeup_tracer(struct trace_array *tr) */ smp_wmb(); - register_ftrace_function(&trace_ops); - - if (tracing_is_enabled()) - tracer_enabled = 1; - else - tracer_enabled = 0; + if (start_func_tracer(tr, is_graph())) + printk(KERN_ERR "failed to start wakeup tracer\n"); return; fail_deprobe_wake_new: - unregister_trace_sched_wakeup_new(probe_wakeup); + unregister_trace_sched_wakeup_new(probe_wakeup, NULL); fail_deprobe: - unregister_trace_sched_wakeup(probe_wakeup); + unregister_trace_sched_wakeup(probe_wakeup, NULL); } static void stop_wakeup_tracer(struct trace_array *tr) { tracer_enabled = 0; - unregister_ftrace_function(&trace_ops); - unregister_trace_sched_switch(probe_wakeup_sched_switch); - unregister_trace_sched_wakeup_new(probe_wakeup); - unregister_trace_sched_wakeup(probe_wakeup); - unregister_trace_sched_migrate_task(probe_wakeup_migrate_task); + stop_func_tracer(tr, is_graph()); + unregister_trace_sched_switch(probe_wakeup_sched_switch, NULL); + unregister_trace_sched_wakeup_new(probe_wakeup, NULL); + unregister_trace_sched_wakeup(probe_wakeup, NULL); + unregister_trace_sched_migrate_task(probe_wakeup_migrate_task, NULL); } +static bool wakeup_busy; + static int __wakeup_tracer_init(struct trace_array *tr) { - save_lat_flag = trace_flags & TRACE_ITER_LATENCY_FMT; - trace_flags |= TRACE_ITER_LATENCY_FMT; + save_flags = trace_flags; - tracing_max_latency = 0; + /* non overwrite screws up the latency tracers */ + set_tracer_flag(tr, TRACE_ITER_OVERWRITE, 1); + set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, 1); + + tr->max_latency = 0; wakeup_trace = tr; + ftrace_init_array_ops(tr, wakeup_tracer_call); start_wakeup_tracer(tr); + + wakeup_busy = true; return 0; } static int wakeup_tracer_init(struct trace_array *tr) { + if (wakeup_busy) + return -EBUSY; + + wakeup_dl = 0; wakeup_rt = 0; return __wakeup_tracer_init(tr); } static int wakeup_rt_tracer_init(struct trace_array *tr) { + if (wakeup_busy) + return -EBUSY; + + wakeup_dl = 0; wakeup_rt = 1; return __wakeup_tracer_init(tr); } +static int wakeup_dl_tracer_init(struct trace_array *tr) +{ + if (wakeup_busy) + return -EBUSY; + + wakeup_dl = 1; + wakeup_rt = 0; + return __wakeup_tracer_init(tr); +} + static void wakeup_tracer_reset(struct trace_array *tr) { + int lat_flag = save_flags & TRACE_ITER_LATENCY_FMT; + int overwrite_flag = save_flags & TRACE_ITER_OVERWRITE; + stop_wakeup_tracer(tr); /* make sure we put back any tasks we are tracing */ wakeup_reset(tr); - if (!save_lat_flag) - trace_flags &= ~TRACE_ITER_LATENCY_FMT; + set_tracer_flag(tr, TRACE_ITER_LATENCY_FMT, lat_flag); + set_tracer_flag(tr, TRACE_ITER_OVERWRITE, overwrite_flag); + ftrace_reset_array_ops(tr); + wakeup_busy = false; } static void wakeup_tracer_start(struct trace_array *tr) @@ -378,10 +683,19 @@ static struct tracer wakeup_tracer __read_mostly = .reset = wakeup_tracer_reset, .start = wakeup_tracer_start, .stop = wakeup_tracer_stop, - .print_max = 1, + .print_max = true, + .print_header = wakeup_print_header, + .print_line = wakeup_print_line, + .flags = &tracer_flags, + .set_flag = wakeup_set_flag, + .flag_changed = wakeup_flag_changed, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_wakeup, #endif + .open = wakeup_trace_open, + .close = wakeup_trace_close, + .allow_instances = true, + .use_max_tr = true, }; static struct tracer wakeup_rt_tracer __read_mostly = @@ -391,11 +705,40 @@ static struct tracer wakeup_rt_tracer __read_mostly = .reset = wakeup_tracer_reset, .start = wakeup_tracer_start, .stop = wakeup_tracer_stop, - .wait_pipe = poll_wait_pipe, - .print_max = 1, + .print_max = true, + .print_header = wakeup_print_header, + .print_line = wakeup_print_line, + .flags = &tracer_flags, + .set_flag = wakeup_set_flag, + .flag_changed = wakeup_flag_changed, #ifdef CONFIG_FTRACE_SELFTEST .selftest = trace_selftest_startup_wakeup, #endif + .open = wakeup_trace_open, + .close = wakeup_trace_close, + .allow_instances = true, + .use_max_tr = true, +}; + +static struct tracer wakeup_dl_tracer __read_mostly = +{ + .name = "wakeup_dl", + .init = wakeup_dl_tracer_init, + .reset = wakeup_tracer_reset, + .start = wakeup_tracer_start, + .stop = wakeup_tracer_stop, + .print_max = true, + .print_header = wakeup_print_header, + .print_line = wakeup_print_line, + .flags = &tracer_flags, + .set_flag = wakeup_set_flag, + .flag_changed = wakeup_flag_changed, +#ifdef CONFIG_FTRACE_SELFTEST + .selftest = trace_selftest_startup_wakeup, +#endif + .open = wakeup_trace_open, + .close = wakeup_trace_close, + .use_max_tr = true, }; __init static int init_wakeup_tracer(void) @@ -410,6 +753,10 @@ __init static int init_wakeup_tracer(void) if (ret) return ret; + ret = register_tracer(&wakeup_dl_tracer); + if (ret) + return ret; + return 0; } -device_initcall(init_wakeup_tracer); +core_initcall(init_wakeup_tracer); |
