135e8e302SSteven Rostedt /* 235e8e302SSteven Rostedt * trace context switch 335e8e302SSteven Rostedt * 435e8e302SSteven Rostedt * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com> 535e8e302SSteven Rostedt * 635e8e302SSteven Rostedt */ 735e8e302SSteven Rostedt #include <linux/module.h> 835e8e302SSteven Rostedt #include <linux/fs.h> 935e8e302SSteven Rostedt #include <linux/debugfs.h> 1035e8e302SSteven Rostedt #include <linux/kallsyms.h> 1135e8e302SSteven Rostedt #include <linux/uaccess.h> 1235e8e302SSteven Rostedt #include <linux/ftrace.h> 13b07c3f19SMathieu Desnoyers #include <trace/sched.h> 1435e8e302SSteven Rostedt 1535e8e302SSteven Rostedt #include "trace.h" 1635e8e302SSteven Rostedt 1735e8e302SSteven Rostedt static struct trace_array *ctx_trace; 1835e8e302SSteven Rostedt static int __read_mostly tracer_enabled; 195b82a1b0SMathieu Desnoyers static atomic_t sched_ref; 2035e8e302SSteven Rostedt 21e309b41dSIngo Molnar static void 22b07c3f19SMathieu Desnoyers probe_sched_switch(struct rq *__rq, struct task_struct *prev, 235b82a1b0SMathieu Desnoyers struct task_struct *next) 2435e8e302SSteven Rostedt { 2535e8e302SSteven Rostedt struct trace_array_cpu *data; 2635e8e302SSteven Rostedt unsigned long flags; 2735e8e302SSteven Rostedt long disabled; 2835e8e302SSteven Rostedt int cpu; 2935e8e302SSteven Rostedt 30b07c3f19SMathieu Desnoyers if (!atomic_read(&sched_ref)) 31b07c3f19SMathieu Desnoyers return; 32b07c3f19SMathieu Desnoyers 3341bc8144SSteven Rostedt tracing_record_cmdline(prev); 3441bc8144SSteven Rostedt tracing_record_cmdline(next); 3541bc8144SSteven Rostedt 3635e8e302SSteven Rostedt if (!tracer_enabled) 3735e8e302SSteven Rostedt return; 3835e8e302SSteven Rostedt 3918cef379SSteven Rostedt local_irq_save(flags); 4035e8e302SSteven Rostedt cpu = raw_smp_processor_id(); 41b07c3f19SMathieu Desnoyers data = ctx_trace->data[cpu]; 4235e8e302SSteven Rostedt disabled = atomic_inc_return(&data->disabled); 4335e8e302SSteven Rostedt 444d9493c9SIngo Molnar if (likely(disabled == 1)) 45b07c3f19SMathieu Desnoyers tracing_sched_switch_trace(ctx_trace, data, prev, next, flags); 4635e8e302SSteven Rostedt 4735e8e302SSteven Rostedt atomic_dec(&data->disabled); 4818cef379SSteven Rostedt local_irq_restore(flags); 4935e8e302SSteven Rostedt } 5035e8e302SSteven Rostedt 515b82a1b0SMathieu Desnoyers static void 52b07c3f19SMathieu Desnoyers probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee) 535b82a1b0SMathieu Desnoyers { 5457422797SIngo Molnar struct trace_array_cpu *data; 5557422797SIngo Molnar unsigned long flags; 5657422797SIngo Molnar long disabled; 5757422797SIngo Molnar int cpu; 5857422797SIngo Molnar 59b07c3f19SMathieu Desnoyers if (!likely(tracer_enabled)) 6057422797SIngo Molnar return; 6157422797SIngo Molnar 62b07c3f19SMathieu Desnoyers tracing_record_cmdline(current); 63d9af56fbSIngo Molnar 6457422797SIngo Molnar local_irq_save(flags); 6557422797SIngo Molnar cpu = raw_smp_processor_id(); 66b07c3f19SMathieu Desnoyers data = ctx_trace->data[cpu]; 6757422797SIngo Molnar disabled = atomic_inc_return(&data->disabled); 6857422797SIngo Molnar 694d9493c9SIngo Molnar if (likely(disabled == 1)) 70b07c3f19SMathieu Desnoyers tracing_sched_wakeup_trace(ctx_trace, data, wakee, current, 71b07c3f19SMathieu Desnoyers flags); 7257422797SIngo Molnar 7357422797SIngo Molnar atomic_dec(&data->disabled); 7457422797SIngo Molnar local_irq_restore(flags); 7557422797SIngo Molnar } 7657422797SIngo Molnar 77e309b41dSIngo Molnar static void sched_switch_reset(struct trace_array *tr) 7835e8e302SSteven Rostedt { 7935e8e302SSteven Rostedt int cpu; 8035e8e302SSteven Rostedt 81750ed1a4SIngo Molnar tr->time_start = ftrace_now(tr->cpu); 8235e8e302SSteven Rostedt 8335e8e302SSteven Rostedt for_each_online_cpu(cpu) 8435e8e302SSteven Rostedt tracing_reset(tr->data[cpu]); 8535e8e302SSteven Rostedt } 8635e8e302SSteven Rostedt 875b82a1b0SMathieu Desnoyers static int tracing_sched_register(void) 885b82a1b0SMathieu Desnoyers { 895b82a1b0SMathieu Desnoyers int ret; 905b82a1b0SMathieu Desnoyers 91b07c3f19SMathieu Desnoyers ret = register_trace_sched_wakeup(probe_sched_wakeup); 925b82a1b0SMathieu Desnoyers if (ret) { 93b07c3f19SMathieu Desnoyers pr_info("wakeup trace: Couldn't activate tracepoint" 945b82a1b0SMathieu Desnoyers " probe to kernel_sched_wakeup\n"); 955b82a1b0SMathieu Desnoyers return ret; 965b82a1b0SMathieu Desnoyers } 975b82a1b0SMathieu Desnoyers 98b07c3f19SMathieu Desnoyers ret = register_trace_sched_wakeup_new(probe_sched_wakeup); 995b82a1b0SMathieu Desnoyers if (ret) { 100b07c3f19SMathieu Desnoyers pr_info("wakeup trace: Couldn't activate tracepoint" 1015b82a1b0SMathieu Desnoyers " probe to kernel_sched_wakeup_new\n"); 1025b82a1b0SMathieu Desnoyers goto fail_deprobe; 1035b82a1b0SMathieu Desnoyers } 1045b82a1b0SMathieu Desnoyers 105b07c3f19SMathieu Desnoyers ret = register_trace_sched_switch(probe_sched_switch); 1065b82a1b0SMathieu Desnoyers if (ret) { 107b07c3f19SMathieu Desnoyers pr_info("sched trace: Couldn't activate tracepoint" 1085b82a1b0SMathieu Desnoyers " probe to kernel_sched_schedule\n"); 1095b82a1b0SMathieu Desnoyers goto fail_deprobe_wake_new; 1105b82a1b0SMathieu Desnoyers } 1115b82a1b0SMathieu Desnoyers 1125b82a1b0SMathieu Desnoyers return ret; 1135b82a1b0SMathieu Desnoyers fail_deprobe_wake_new: 114b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup_new(probe_sched_wakeup); 1155b82a1b0SMathieu Desnoyers fail_deprobe: 116b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup(probe_sched_wakeup); 1175b82a1b0SMathieu Desnoyers return ret; 1185b82a1b0SMathieu Desnoyers } 1195b82a1b0SMathieu Desnoyers 1205b82a1b0SMathieu Desnoyers static void tracing_sched_unregister(void) 1215b82a1b0SMathieu Desnoyers { 122b07c3f19SMathieu Desnoyers unregister_trace_sched_switch(probe_sched_switch); 123b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup_new(probe_sched_wakeup); 124b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup(probe_sched_wakeup); 1255b82a1b0SMathieu Desnoyers } 1265b82a1b0SMathieu Desnoyers 127f2252935SIngo Molnar static void tracing_start_sched_switch(void) 1285b82a1b0SMathieu Desnoyers { 1295b82a1b0SMathieu Desnoyers long ref; 1305b82a1b0SMathieu Desnoyers 1315b82a1b0SMathieu Desnoyers ref = atomic_inc_return(&sched_ref); 1325b82a1b0SMathieu Desnoyers if (ref == 1) 1335b82a1b0SMathieu Desnoyers tracing_sched_register(); 1345b82a1b0SMathieu Desnoyers } 1355b82a1b0SMathieu Desnoyers 136f2252935SIngo Molnar static void tracing_stop_sched_switch(void) 1375b82a1b0SMathieu Desnoyers { 1385b82a1b0SMathieu Desnoyers long ref; 1395b82a1b0SMathieu Desnoyers 1405b82a1b0SMathieu Desnoyers ref = atomic_dec_and_test(&sched_ref); 1415b82a1b0SMathieu Desnoyers if (ref) 1425b82a1b0SMathieu Desnoyers tracing_sched_unregister(); 1435b82a1b0SMathieu Desnoyers } 1445b82a1b0SMathieu Desnoyers 14541bc8144SSteven Rostedt void tracing_start_cmdline_record(void) 14641bc8144SSteven Rostedt { 14741bc8144SSteven Rostedt tracing_start_sched_switch(); 14841bc8144SSteven Rostedt } 14941bc8144SSteven Rostedt 15041bc8144SSteven Rostedt void tracing_stop_cmdline_record(void) 15141bc8144SSteven Rostedt { 15241bc8144SSteven Rostedt tracing_stop_sched_switch(); 15341bc8144SSteven Rostedt } 15441bc8144SSteven Rostedt 155e309b41dSIngo Molnar static void start_sched_trace(struct trace_array *tr) 15635e8e302SSteven Rostedt { 15735e8e302SSteven Rostedt sched_switch_reset(tr); 15841bc8144SSteven Rostedt tracing_start_cmdline_record(); 159007c05d4SSteven Rostedt tracer_enabled = 1; 16035e8e302SSteven Rostedt } 16135e8e302SSteven Rostedt 162e309b41dSIngo Molnar static void stop_sched_trace(struct trace_array *tr) 16335e8e302SSteven Rostedt { 16435e8e302SSteven Rostedt tracer_enabled = 0; 165007c05d4SSteven Rostedt tracing_stop_cmdline_record(); 16635e8e302SSteven Rostedt } 16735e8e302SSteven Rostedt 168e309b41dSIngo Molnar static void sched_switch_trace_init(struct trace_array *tr) 16935e8e302SSteven Rostedt { 17035e8e302SSteven Rostedt ctx_trace = tr; 17135e8e302SSteven Rostedt 17235e8e302SSteven Rostedt if (tr->ctrl) 17335e8e302SSteven Rostedt start_sched_trace(tr); 17435e8e302SSteven Rostedt } 17535e8e302SSteven Rostedt 176e309b41dSIngo Molnar static void sched_switch_trace_reset(struct trace_array *tr) 17735e8e302SSteven Rostedt { 17835e8e302SSteven Rostedt if (tr->ctrl) 17935e8e302SSteven Rostedt stop_sched_trace(tr); 18035e8e302SSteven Rostedt } 18135e8e302SSteven Rostedt 18235e8e302SSteven Rostedt static void sched_switch_trace_ctrl_update(struct trace_array *tr) 18335e8e302SSteven Rostedt { 18435e8e302SSteven Rostedt /* When starting a new trace, reset the buffers */ 18535e8e302SSteven Rostedt if (tr->ctrl) 18635e8e302SSteven Rostedt start_sched_trace(tr); 18735e8e302SSteven Rostedt else 18835e8e302SSteven Rostedt stop_sched_trace(tr); 18935e8e302SSteven Rostedt } 19035e8e302SSteven Rostedt 19135e8e302SSteven Rostedt static struct tracer sched_switch_trace __read_mostly = 19235e8e302SSteven Rostedt { 19335e8e302SSteven Rostedt .name = "sched_switch", 19435e8e302SSteven Rostedt .init = sched_switch_trace_init, 19535e8e302SSteven Rostedt .reset = sched_switch_trace_reset, 19635e8e302SSteven Rostedt .ctrl_update = sched_switch_trace_ctrl_update, 19760a11774SSteven Rostedt #ifdef CONFIG_FTRACE_SELFTEST 19860a11774SSteven Rostedt .selftest = trace_selftest_startup_sched_switch, 19960a11774SSteven Rostedt #endif 20035e8e302SSteven Rostedt }; 20135e8e302SSteven Rostedt 20235e8e302SSteven Rostedt __init static int init_sched_switch_trace(void) 20335e8e302SSteven Rostedt { 2045b82a1b0SMathieu Desnoyers int ret = 0; 2055b82a1b0SMathieu Desnoyers 2065b82a1b0SMathieu Desnoyers if (atomic_read(&sched_ref)) 2075b82a1b0SMathieu Desnoyers ret = tracing_sched_register(); 2085b82a1b0SMathieu Desnoyers if (ret) { 2095b82a1b0SMathieu Desnoyers pr_info("error registering scheduler trace\n"); 2105b82a1b0SMathieu Desnoyers return ret; 2115b82a1b0SMathieu Desnoyers } 21235e8e302SSteven Rostedt return register_tracer(&sched_switch_trace); 21335e8e302SSteven Rostedt } 21435e8e302SSteven Rostedt device_initcall(init_sched_switch_trace); 215