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author | Timothy Pearson <tpearson@raptorengineering.com> | 2017-08-23 14:45:25 -0500 |
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committer | Timothy Pearson <tpearson@raptorengineering.com> | 2017-08-23 14:45:25 -0500 |
commit | fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204 (patch) | |
tree | 22962a4387943edc841c72a4e636a068c66d58fd /kernel/trace/trace_sched_switch.c | |
download | ast2050-linux-kernel-fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204.zip ast2050-linux-kernel-fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204.tar.gz |
Initial import of modified Linux 2.6.28 tree
Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y
Diffstat (limited to 'kernel/trace/trace_sched_switch.c')
-rw-r--r-- | kernel/trace/trace_sched_switch.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c new file mode 100644 index 0000000..b8f56be --- /dev/null +++ b/kernel/trace/trace_sched_switch.c @@ -0,0 +1,211 @@ +/* + * 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/sched.h> + +#include "trace.h" + +static struct trace_array *ctx_trace; +static int __read_mostly tracer_enabled; +static atomic_t sched_ref; + +static void +probe_sched_switch(struct rq *__rq, struct task_struct *prev, + struct task_struct *next) +{ + struct trace_array_cpu *data; + unsigned long flags; + int cpu; + int pc; + + if (!atomic_read(&sched_ref)) + return; + + tracing_record_cmdline(prev); + tracing_record_cmdline(next); + + if (!tracer_enabled) + 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, data, prev, next, flags, pc); + + local_irq_restore(flags); +} + +static void +probe_sched_wakeup(struct rq *__rq, struct task_struct *wakee) +{ + struct trace_array_cpu *data; + unsigned long flags; + int cpu, pc; + + if (!likely(tracer_enabled)) + return; + + pc = preempt_count(); + tracing_record_cmdline(current); + + 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, data, wakee, current, + flags, pc); + + local_irq_restore(flags); +} + +static void sched_switch_reset(struct trace_array *tr) +{ + int cpu; + + tr->time_start = ftrace_now(tr->cpu); + + for_each_online_cpu(cpu) + tracing_reset(tr, cpu); +} + +static int tracing_sched_register(void) +{ + int ret; + + ret = register_trace_sched_wakeup(probe_sched_wakeup); + 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); + 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); + if (ret) { + pr_info("sched trace: Couldn't activate tracepoint" + " probe to kernel_sched_schedule\n"); + goto fail_deprobe_wake_new; + } + + return ret; +fail_deprobe_wake_new: + unregister_trace_sched_wakeup_new(probe_sched_wakeup); +fail_deprobe: + unregister_trace_sched_wakeup(probe_sched_wakeup); + return ret; +} + +static void tracing_sched_unregister(void) +{ + unregister_trace_sched_switch(probe_sched_switch); + unregister_trace_sched_wakeup_new(probe_sched_wakeup); + unregister_trace_sched_wakeup(probe_sched_wakeup); +} + +static void tracing_start_sched_switch(void) +{ + long ref; + + ref = atomic_inc_return(&sched_ref); + if (ref == 1) + tracing_sched_register(); +} + +static void tracing_stop_sched_switch(void) +{ + long ref; + + ref = atomic_dec_and_test(&sched_ref); + if (ref) + tracing_sched_unregister(); +} + +void tracing_start_cmdline_record(void) +{ + tracing_start_sched_switch(); +} + +void tracing_stop_cmdline_record(void) +{ + tracing_stop_sched_switch(); +} + +static void start_sched_trace(struct trace_array *tr) +{ + sched_switch_reset(tr); + tracing_start_cmdline_record(); + tracer_enabled = 1; +} + +static void stop_sched_trace(struct trace_array *tr) +{ + tracer_enabled = 0; + tracing_stop_cmdline_record(); +} + +static void sched_switch_trace_init(struct trace_array *tr) +{ + ctx_trace = tr; + + if (tr->ctrl) + start_sched_trace(tr); +} + +static void sched_switch_trace_reset(struct trace_array *tr) +{ + if (tr->ctrl) + stop_sched_trace(tr); +} + +static void sched_switch_trace_ctrl_update(struct trace_array *tr) +{ + /* When starting a new trace, reset the buffers */ + if (tr->ctrl) + start_sched_trace(tr); + else + stop_sched_trace(tr); +} + +static struct tracer sched_switch_trace __read_mostly = +{ + .name = "sched_switch", + .init = sched_switch_trace_init, + .reset = sched_switch_trace_reset, + .ctrl_update = sched_switch_trace_ctrl_update, +#ifdef CONFIG_FTRACE_SELFTEST + .selftest = trace_selftest_startup_sched_switch, +#endif +}; + +__init static int init_sched_switch_trace(void) +{ + int ret = 0; + + if (atomic_read(&sched_ref)) + ret = tracing_sched_register(); + if (ret) { + pr_info("error registering scheduler trace\n"); + return ret; + } + return register_tracer(&sched_switch_trace); +} +device_initcall(init_sched_switch_trace); |