diff options
Diffstat (limited to 'kernel/trace/trace_sched_switch.c')
| -rw-r--r-- | kernel/trace/trace_sched_switch.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c new file mode 100644 index 00000000..7e62c0a1 --- /dev/null +++ b/kernel/trace/trace_sched_switch.c @@ -0,0 +1,249 @@ +/* + * trace context switch + * + * Copyright (C) 2007 Steven Rostedt <srostedt@redhat.com> + * + */ +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/debugfs.h> +#include <linux/kallsyms.h> +#include <linux/uaccess.h> +#include <linux/ftrace.h> +#include <trace/events/sched.h> + +#include "trace.h" + +static struct trace_array *ctx_trace; +static int __read_mostly tracer_enabled; +static int sched_ref; +static DEFINE_MUTEX(sched_register_mutex); +static int sched_stopped; + + +void +tracing_sched_switch_trace(struct trace_array *tr, + struct task_struct *prev, + struct task_struct *next, + unsigned long flags, int pc) +{ + struct ftrace_event_call *call = &event_context_switch; + struct ring_buffer *buffer = tr->buffer; + struct ring_buffer_event *event; + struct ctx_switch_entry *entry; + + event = trace_buffer_lock_reserve(buffer, TRACE_CTX, + sizeof(*entry), flags, pc); + if (!event) + return; + entry = ring_buffer_event_data(event); + entry->prev_pid = prev->pid; + entry->prev_prio = prev->prio; + entry->prev_state = prev->state; + entry->next_pid = next->pid; + entry->next_prio = next->prio; + entry->next_state = next->state; + entry->next_cpu = task_cpu(next); + + if (!filter_check_discard(call, entry, buffer, event)) + trace_buffer_unlock_commit(buffer, event, flags, pc); +} + +static void +probe_sched_switch(void *ignore, struct task_struct *prev, struct task_struct *next) +{ + struct trace_array_cpu *data; + unsigned long flags; + int cpu; + int pc; + + if (unlikely(!sched_ref)) + return; + + tracing_record_cmdline(prev); + tracing_record_cmdline(next); + + if (!tracer_enabled || sched_stopped) + return; + + pc = preempt_count(); + local_irq_save(flags); + cpu = raw_smp_processor_id(); + data = ctx_trace->data[cpu]; + + if (likely(!atomic_read(&data->disabled))) + tracing_sched_switch_trace(ctx_trace, prev, next, flags, pc); + + local_irq_restore(flags); +} + +void +tracing_sched_wakeup_trace(struct trace_array *tr, + struct task_struct *wakee, + struct task_struct *curr, + unsigned long flags, int pc) +{ + struct ftrace_event_call *call = &event_wakeup; + struct ring_buffer_event *event; + struct ctx_switch_entry *entry; + struct ring_buffer *buffer = tr->buffer; + + event = trace_buffer_lock_reserve(buffer, TRACE_WAKE, + sizeof(*entry), flags, pc); + if (!event) + return; + entry = ring_buffer_event_data(event); + entry->prev_pid = curr->pid; + entry->prev_prio = curr->prio; + entry->prev_state = curr->state; + entry->next_pid = wakee->pid; + entry->next_prio = wakee->prio; + entry->next_state = wakee->state; + entry->next_cpu = task_cpu(wakee); + + if (!filter_check_discard(call, entry, buffer, event)) + ring_buffer_unlock_commit(buffer, event); + ftrace_trace_stack(tr->buffer, flags, 6, pc); + ftrace_trace_userstack(tr->buffer, flags, pc); +} + +static void +probe_sched_wakeup(void *ignore, struct task_struct *wakee, int success) +{ + struct trace_array_cpu *data; + unsigned long flags; + int cpu, pc; + + if (unlikely(!sched_ref)) + return; + + tracing_record_cmdline(current); + + if (!tracer_enabled || sched_stopped) + return; + + pc = preempt_count(); + local_irq_save(flags); + cpu = raw_smp_processor_id(); + data = ctx_trace->data[cpu]; + + if (likely(!atomic_read(&data->disabled))) + tracing_sched_wakeup_trace(ctx_trace, wakee, current, + flags, pc); + + local_irq_restore(flags); +} + +static int tracing_sched_register(void) +{ + int ret; + + ret = register_trace_sched_wakeup(probe_sched_wakeup, NULL); + if (ret) { + pr_info("wakeup trace: Couldn't activate tracepoint" + " probe to kernel_sched_wakeup\n"); + return ret; + } + + ret = register_trace_sched_wakeup_new(probe_sched_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_sched_switch, NULL); + if (ret) { + pr_info("sched trace: Couldn't activate tracepoint" + " probe to kernel_sched_switch\n"); + goto fail_deprobe_wake_new; + } + + return ret; +fail_deprobe_wake_new: + unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL); +fail_deprobe: + unregister_trace_sched_wakeup(probe_sched_wakeup, NULL); + return ret; +} + +static void tracing_sched_unregister(void) +{ + unregister_trace_sched_switch(probe_sched_switch, NULL); + unregister_trace_sched_wakeup_new(probe_sched_wakeup, NULL); + unregister_trace_sched_wakeup(probe_sched_wakeup, NULL); +} + +static void tracing_start_sched_switch(void) +{ + mutex_lock(&sched_register_mutex); + if (!(sched_ref++)) + tracing_sched_register(); + mutex_unlock(&sched_register_mutex); +} + +static void tracing_stop_sched_switch(void) +{ + mutex_lock(&sched_register_mutex); + if (!(--sched_ref)) + tracing_sched_unregister(); + mutex_unlock(&sched_register_mutex); +} + +void tracing_start_cmdline_record(void) +{ + tracing_start_sched_switch(); +} + +void tracing_stop_cmdline_record(void) +{ + tracing_stop_sched_switch(); +} + +/** + * tracing_start_sched_switch_record - start tracing context switches + * + * Turns on context switch tracing for a tracer. + */ +void tracing_start_sched_switch_record(void) +{ + if (unlikely(!ctx_trace)) { + WARN_ON(1); + return; + } + + tracing_start_sched_switch(); + + mutex_lock(&sched_register_mutex); + tracer_enabled++; + mutex_unlock(&sched_register_mutex); +} + +/** + * tracing_stop_sched_switch_record - start tracing context switches + * + * Turns off context switch tracing for a tracer. + */ +void tracing_stop_sched_switch_record(void) +{ + mutex_lock(&sched_register_mutex); + tracer_enabled--; + WARN_ON(tracer_enabled < 0); + mutex_unlock(&sched_register_mutex); + + tracing_stop_sched_switch(); +} + +/** + * tracing_sched_switch_assign_trace - assign a trace array for ctx switch + * @tr: trace array pointer to assign + * + * Some tracers might want to record the context switches in their + * trace. This function lets those tracers assign the trace array + * to use. + */ +void tracing_sched_switch_assign_trace(struct trace_array *tr) +{ + ctx_trace = tr; +} + |