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 int cpu; 2838697053SSteven Rostedt int pc; 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 3938697053SSteven Rostedt pc = preempt_count(); 4018cef379SSteven Rostedt local_irq_save(flags); 4135e8e302SSteven Rostedt cpu = raw_smp_processor_id(); 42b07c3f19SMathieu Desnoyers data = ctx_trace->data[cpu]; 4335e8e302SSteven Rostedt 443ea2e6d7SSteven Rostedt if (likely(!atomic_read(&data->disabled))) 4538697053SSteven Rostedt tracing_sched_switch_trace(ctx_trace, data, prev, next, flags, pc); 4635e8e302SSteven Rostedt 4718cef379SSteven Rostedt local_irq_restore(flags); 4835e8e302SSteven Rostedt } 4935e8e302SSteven Rostedt 505b82a1b0SMathieu Desnoyers static void 51b07c3f19SMathieu Desnoyers probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee) 525b82a1b0SMathieu Desnoyers { 5357422797SIngo Molnar struct trace_array_cpu *data; 5457422797SIngo Molnar unsigned long flags; 5538697053SSteven Rostedt int cpu, pc; 5657422797SIngo Molnar 57b07c3f19SMathieu Desnoyers if (!likely(tracer_enabled)) 5857422797SIngo Molnar return; 5957422797SIngo Molnar 6038697053SSteven Rostedt pc = preempt_count(); 61b07c3f19SMathieu Desnoyers tracing_record_cmdline(current); 62d9af56fbSIngo Molnar 6357422797SIngo Molnar local_irq_save(flags); 6457422797SIngo Molnar cpu = raw_smp_processor_id(); 65b07c3f19SMathieu Desnoyers data = ctx_trace->data[cpu]; 6657422797SIngo Molnar 673ea2e6d7SSteven Rostedt if (likely(!atomic_read(&data->disabled))) 68b07c3f19SMathieu Desnoyers tracing_sched_wakeup_trace(ctx_trace, data, wakee, current, 6938697053SSteven Rostedt flags, pc); 7057422797SIngo Molnar 7157422797SIngo Molnar local_irq_restore(flags); 7257422797SIngo Molnar } 7357422797SIngo Molnar 74e309b41dSIngo Molnar static void sched_switch_reset(struct trace_array *tr) 7535e8e302SSteven Rostedt { 7635e8e302SSteven Rostedt int cpu; 7735e8e302SSteven Rostedt 78750ed1a4SIngo Molnar tr->time_start = ftrace_now(tr->cpu); 7935e8e302SSteven Rostedt 8035e8e302SSteven Rostedt for_each_online_cpu(cpu) 813928a8a2SSteven Rostedt tracing_reset(tr, cpu); 8235e8e302SSteven Rostedt } 8335e8e302SSteven Rostedt 845b82a1b0SMathieu Desnoyers static int tracing_sched_register(void) 855b82a1b0SMathieu Desnoyers { 865b82a1b0SMathieu Desnoyers int ret; 875b82a1b0SMathieu Desnoyers 88b07c3f19SMathieu Desnoyers ret = register_trace_sched_wakeup(probe_sched_wakeup); 895b82a1b0SMathieu Desnoyers if (ret) { 90b07c3f19SMathieu Desnoyers pr_info("wakeup trace: Couldn't activate tracepoint" 915b82a1b0SMathieu Desnoyers " probe to kernel_sched_wakeup\n"); 925b82a1b0SMathieu Desnoyers return ret; 935b82a1b0SMathieu Desnoyers } 945b82a1b0SMathieu Desnoyers 95b07c3f19SMathieu Desnoyers ret = register_trace_sched_wakeup_new(probe_sched_wakeup); 965b82a1b0SMathieu Desnoyers if (ret) { 97b07c3f19SMathieu Desnoyers pr_info("wakeup trace: Couldn't activate tracepoint" 985b82a1b0SMathieu Desnoyers " probe to kernel_sched_wakeup_new\n"); 995b82a1b0SMathieu Desnoyers goto fail_deprobe; 1005b82a1b0SMathieu Desnoyers } 1015b82a1b0SMathieu Desnoyers 102b07c3f19SMathieu Desnoyers ret = register_trace_sched_switch(probe_sched_switch); 1035b82a1b0SMathieu Desnoyers if (ret) { 104b07c3f19SMathieu Desnoyers pr_info("sched trace: Couldn't activate tracepoint" 1055b82a1b0SMathieu Desnoyers " probe to kernel_sched_schedule\n"); 1065b82a1b0SMathieu Desnoyers goto fail_deprobe_wake_new; 1075b82a1b0SMathieu Desnoyers } 1085b82a1b0SMathieu Desnoyers 1095b82a1b0SMathieu Desnoyers return ret; 1105b82a1b0SMathieu Desnoyers fail_deprobe_wake_new: 111b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup_new(probe_sched_wakeup); 1125b82a1b0SMathieu Desnoyers fail_deprobe: 113b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup(probe_sched_wakeup); 1145b82a1b0SMathieu Desnoyers return ret; 1155b82a1b0SMathieu Desnoyers } 1165b82a1b0SMathieu Desnoyers 1175b82a1b0SMathieu Desnoyers static void tracing_sched_unregister(void) 1185b82a1b0SMathieu Desnoyers { 119b07c3f19SMathieu Desnoyers unregister_trace_sched_switch(probe_sched_switch); 120b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup_new(probe_sched_wakeup); 121b07c3f19SMathieu Desnoyers unregister_trace_sched_wakeup(probe_sched_wakeup); 1225b82a1b0SMathieu Desnoyers } 1235b82a1b0SMathieu Desnoyers 124f2252935SIngo Molnar static void tracing_start_sched_switch(void) 1255b82a1b0SMathieu Desnoyers { 1265b82a1b0SMathieu Desnoyers long ref; 1275b82a1b0SMathieu Desnoyers 1285b82a1b0SMathieu Desnoyers ref = atomic_inc_return(&sched_ref); 1295b82a1b0SMathieu Desnoyers if (ref == 1) 1305b82a1b0SMathieu Desnoyers tracing_sched_register(); 1315b82a1b0SMathieu Desnoyers } 1325b82a1b0SMathieu Desnoyers 133f2252935SIngo Molnar static void tracing_stop_sched_switch(void) 1345b82a1b0SMathieu Desnoyers { 1355b82a1b0SMathieu Desnoyers long ref; 1365b82a1b0SMathieu Desnoyers 1375b82a1b0SMathieu Desnoyers ref = atomic_dec_and_test(&sched_ref); 1385b82a1b0SMathieu Desnoyers if (ref) 1395b82a1b0SMathieu Desnoyers tracing_sched_unregister(); 1405b82a1b0SMathieu Desnoyers } 1415b82a1b0SMathieu Desnoyers 14241bc8144SSteven Rostedt void tracing_start_cmdline_record(void) 14341bc8144SSteven Rostedt { 14441bc8144SSteven Rostedt tracing_start_sched_switch(); 14541bc8144SSteven Rostedt } 14641bc8144SSteven Rostedt 14741bc8144SSteven Rostedt void tracing_stop_cmdline_record(void) 14841bc8144SSteven Rostedt { 14941bc8144SSteven Rostedt tracing_stop_sched_switch(); 15041bc8144SSteven Rostedt } 15141bc8144SSteven Rostedt 152e309b41dSIngo Molnar static void start_sched_trace(struct trace_array *tr) 15335e8e302SSteven Rostedt { 15435e8e302SSteven Rostedt sched_switch_reset(tr); 15541bc8144SSteven Rostedt tracing_start_cmdline_record(); 156007c05d4SSteven Rostedt tracer_enabled = 1; 15735e8e302SSteven Rostedt } 15835e8e302SSteven Rostedt 159e309b41dSIngo Molnar static void stop_sched_trace(struct trace_array *tr) 16035e8e302SSteven Rostedt { 16135e8e302SSteven Rostedt tracer_enabled = 0; 162007c05d4SSteven Rostedt tracing_stop_cmdline_record(); 16335e8e302SSteven Rostedt } 16435e8e302SSteven Rostedt 165e309b41dSIngo Molnar static void sched_switch_trace_init(struct trace_array *tr) 16635e8e302SSteven Rostedt { 16735e8e302SSteven Rostedt ctx_trace = tr; 16835e8e302SSteven Rostedt 16935e8e302SSteven Rostedt if (tr->ctrl) 17035e8e302SSteven Rostedt start_sched_trace(tr); 17135e8e302SSteven Rostedt } 17235e8e302SSteven Rostedt 173e309b41dSIngo Molnar static void sched_switch_trace_reset(struct trace_array *tr) 17435e8e302SSteven Rostedt { 17535e8e302SSteven Rostedt if (tr->ctrl) 17635e8e302SSteven Rostedt stop_sched_trace(tr); 17735e8e302SSteven Rostedt } 17835e8e302SSteven Rostedt 17935e8e302SSteven Rostedt static void sched_switch_trace_ctrl_update(struct trace_array *tr) 18035e8e302SSteven Rostedt { 18135e8e302SSteven Rostedt /* When starting a new trace, reset the buffers */ 18235e8e302SSteven Rostedt if (tr->ctrl) 18335e8e302SSteven Rostedt start_sched_trace(tr); 18435e8e302SSteven Rostedt else 18535e8e302SSteven Rostedt stop_sched_trace(tr); 18635e8e302SSteven Rostedt } 18735e8e302SSteven Rostedt 18835e8e302SSteven Rostedt static struct tracer sched_switch_trace __read_mostly = 18935e8e302SSteven Rostedt { 19035e8e302SSteven Rostedt .name = "sched_switch", 19135e8e302SSteven Rostedt .init = sched_switch_trace_init, 19235e8e302SSteven Rostedt .reset = sched_switch_trace_reset, 19335e8e302SSteven Rostedt .ctrl_update = sched_switch_trace_ctrl_update, 19460a11774SSteven Rostedt #ifdef CONFIG_FTRACE_SELFTEST 19560a11774SSteven Rostedt .selftest = trace_selftest_startup_sched_switch, 19660a11774SSteven Rostedt #endif 19735e8e302SSteven Rostedt }; 19835e8e302SSteven Rostedt 19935e8e302SSteven Rostedt __init static int init_sched_switch_trace(void) 20035e8e302SSteven Rostedt { 2015b82a1b0SMathieu Desnoyers int ret = 0; 2025b82a1b0SMathieu Desnoyers 2035b82a1b0SMathieu Desnoyers if (atomic_read(&sched_ref)) 2045b82a1b0SMathieu Desnoyers ret = tracing_sched_register(); 2055b82a1b0SMathieu Desnoyers if (ret) { 2065b82a1b0SMathieu Desnoyers pr_info("error registering scheduler trace\n"); 2075b82a1b0SMathieu Desnoyers return ret; 2085b82a1b0SMathieu Desnoyers } 20935e8e302SSteven Rostedt return register_tracer(&sched_switch_trace); 21035e8e302SSteven Rostedt } 21135e8e302SSteven Rostedt device_initcall(init_sched_switch_trace); 212