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d7ad44b697
Impact: enhance boot trace output with scheduling events Use the sched_switch tracer from the boot tracer. We also can trace schedule events inside the initcalls. Sched tracing is disabled after the initcall has finished and then reenabled before the next one is started. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
136 lines
3 KiB
C
136 lines
3 KiB
C
/*
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* ring buffer based initcalls tracer
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*
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* Copyright (C) 2008 Frederic Weisbecker <fweisbec@gmail.com>
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*
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*/
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#include <linux/init.h>
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#include <linux/debugfs.h>
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#include <linux/ftrace.h>
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#include <linux/kallsyms.h>
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#include "trace.h"
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static struct trace_array *boot_trace;
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static bool pre_initcalls_finished;
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/* Tells the boot tracer that the pre_smp_initcalls are finished.
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* So we are ready .
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* It doesn't enable sched events tracing however.
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* You have to call enable_boot_trace to do so.
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*/
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void start_boot_trace(void)
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{
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pre_initcalls_finished = true;
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}
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void enable_boot_trace(void)
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{
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if (pre_initcalls_finished)
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tracing_start_cmdline_record();
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}
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void disable_boot_trace(void)
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{
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if (pre_initcalls_finished)
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tracing_stop_cmdline_record();
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}
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void reset_boot_trace(struct trace_array *tr)
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{
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disable_boot_trace();
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}
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static void boot_trace_init(struct trace_array *tr)
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{
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int cpu;
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boot_trace = tr;
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for_each_cpu_mask(cpu, cpu_possible_map)
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tracing_reset(tr, cpu);
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sched_switch_trace.init(tr);
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}
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static void boot_trace_ctrl_update(struct trace_array *tr)
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{
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if (tr->ctrl)
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enable_boot_trace();
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else
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disable_boot_trace();
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}
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static enum print_line_t initcall_print_line(struct trace_iterator *iter)
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{
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int ret;
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struct trace_entry *entry = iter->ent;
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struct trace_boot *field = (struct trace_boot *)entry;
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struct boot_trace *it = &field->initcall;
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struct trace_seq *s = &iter->seq;
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struct timespec calltime = ktime_to_timespec(it->calltime);
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struct timespec rettime = ktime_to_timespec(it->rettime);
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if (entry->type == TRACE_BOOT) {
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ret = trace_seq_printf(s, "[%5ld.%09ld] calling %s @ %i\n",
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calltime.tv_sec,
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calltime.tv_nsec,
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it->func, it->caller);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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ret = trace_seq_printf(s, "[%5ld.%09ld] initcall %s "
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"returned %d after %lld msecs\n",
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rettime.tv_sec,
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rettime.tv_nsec,
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it->func, it->result, it->duration);
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if (!ret)
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return TRACE_TYPE_PARTIAL_LINE;
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return TRACE_TYPE_HANDLED;
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}
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return TRACE_TYPE_UNHANDLED;
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}
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struct tracer boot_tracer __read_mostly =
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{
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.name = "initcall",
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.init = boot_trace_init,
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.reset = reset_boot_trace,
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.ctrl_update = boot_trace_ctrl_update,
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.print_line = initcall_print_line,
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};
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void trace_boot(struct boot_trace *it, initcall_t fn)
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{
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struct ring_buffer_event *event;
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struct trace_boot *entry;
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struct trace_array_cpu *data;
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unsigned long irq_flags;
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struct trace_array *tr = boot_trace;
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if (!pre_initcalls_finished)
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return;
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/* Get its name now since this function could
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* disappear because it is in the .init section.
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*/
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sprint_symbol(it->func, (unsigned long)fn);
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preempt_disable();
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data = tr->data[smp_processor_id()];
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event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
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&irq_flags);
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if (!event)
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goto out;
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entry = ring_buffer_event_data(event);
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tracing_generic_entry_update(&entry->ent, 0, 0);
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entry->ent.type = TRACE_BOOT;
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entry->initcall = *it;
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ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
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trace_wake_up();
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out:
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preempt_enable();
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}
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