Port ftrace to markers

Porting ftrace to the marker infrastructure.

Don't need to chain to the wakeup tracer from the sched tracer, because markers
support multiple probes connected.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 360ca99..c0b1c69 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2131,38 +2131,6 @@ __trace_special(void *__tr, void *__data,
 }
 #endif
 
-#ifdef CONFIG_CONTEXT_SWITCH_TRACER
-extern void
-ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next);
-extern void
-ftrace_wake_up_task(void *rq, struct task_struct *wakee,
-                   struct task_struct *curr);
-extern void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data);
-extern void
-ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3);
-#else
-static inline void
-ftrace_ctx_switch(void *rq, struct task_struct *prev, struct task_struct *next)
-{
-}
-static inline void
-sched_trace_special(unsigned long p1, unsigned long p2, unsigned long p3)
-{
-}
-static inline void
-ftrace_wake_up_task(void *rq, struct task_struct *wakee,
-                   struct task_struct *curr)
-{
-}
-static inline void ftrace_all_fair_tasks(void *__rq, void *__tr, void *__data)
-{
-}
-static inline void
-ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
-{
-}
-#endif
-
 extern long sched_setaffinity(pid_t pid, const cpumask_t *new_mask);
 extern long sched_getaffinity(pid_t pid, cpumask_t *mask);
 

diff --git a/kernel/sched.c b/kernel/sched.c
index ad95cca..e2e985e 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2500,7 +2500,9 @@ out_activate:
        success = 1;
 
 out_running:
-       ftrace_wake_up_task(rq, p, rq->curr);
+       trace_mark(kernel_sched_wakeup,
+               "pid %d state %ld ## rq %p task %p rq->curr %p",
+               p->pid, p->state, rq, p, rq->curr);
        check_preempt_curr(rq, p);
 
        p->state = TASK_RUNNING;
@@ -2631,7 +2633,9 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
                p->sched_class->task_new(rq, p);
                inc_nr_running(rq);
        }
-       ftrace_wake_up_task(rq, p, rq->curr);
+       trace_mark(kernel_sched_wakeup_new,
+               "pid %d state %ld ## rq %p task %p rq->curr %p",
+               p->pid, p->state, rq, p, rq->curr);
        check_preempt_curr(rq, p);
 #ifdef CONFIG_SMP
        if (p->sched_class->task_wake_up)
@@ -2804,7 +2808,11 @@ context_switch(struct rq *rq, struct task_struct *prev,
        struct mm_struct *mm, *oldmm;
 
        prepare_task_switch(rq, prev, next);
-       ftrace_ctx_switch(rq, prev, next);
+       trace_mark(kernel_sched_schedule,
+               "prev_pid %d next_pid %d prev_state %ld "
+               "## rq %p prev %p next %p",
+               prev->pid, next->pid, prev->state,
+               rq, prev, next);
        mm = next->mm;
        oldmm = prev->active_mm;
        /*

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8845033..f5de060 100644 (file)
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -234,25 +234,10 @@ void update_max_tr_single(struct trace_array *tr,
 
 extern cycle_t ftrace_now(int cpu);
 
-#ifdef CONFIG_SCHED_TRACER
-extern void
-wakeup_sched_switch(struct task_struct *prev, struct task_struct *next);
-extern void
-wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr);
-#else
-static inline void
-wakeup_sched_switch(struct task_struct *prev, struct task_struct *next)
-{
-}
-static inline void
-wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr)
-{
-}
-#endif
-
 #ifdef CONFIG_CONTEXT_SWITCH_TRACER
 typedef void
 (*tracer_switch_func_t)(void *private,
+                       void *__rq,
                        struct task_struct *prev,
                        struct task_struct *next);
 
@@ -262,9 +247,6 @@ struct tracer_switch_ops {
        struct tracer_switch_ops        *next;
 };
 
-extern int register_tracer_switch(struct tracer_switch_ops *ops);
-extern int unregister_tracer_switch(struct tracer_switch_ops *ops);
-
 #endif /* CONFIG_CONTEXT_SWITCH_TRACER */
 
 #ifdef CONFIG_DYNAMIC_FTRACE

diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c
index a337647..d25ffa5 100644 (file)
--- a/kernel/trace/trace_sched_switch.c
+++ b/kernel/trace/trace_sched_switch.c
@@ -16,11 +16,14 @@
 
 static struct trace_array      *ctx_trace;
 static int __read_mostly       tracer_enabled;
+static atomic_t                        sched_ref;
 
 static void
-ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next)
+sched_switch_func(void *private, void *__rq, struct task_struct *prev,
+                       struct task_struct *next)
 {
-       struct trace_array *tr = ctx_trace;
+       struct trace_array **ptr = private;
+       struct trace_array *tr = *ptr;
        struct trace_array_cpu *data;
        unsigned long flags;
        long disabled;
@@ -41,10 +44,40 @@ ctx_switch_func(void *__rq, struct task_struct *prev, struct task_struct *next)
        local_irq_restore(flags);
 }
 
+static notrace void
+sched_switch_callback(void *probe_data, void *call_data,
+                     const char *format, va_list *args)
+{
+       struct task_struct *prev;
+       struct task_struct *next;
+       struct rq *__rq;
+
+       if (!atomic_read(&sched_ref))
+               return;
+
+       /* skip prev_pid %d next_pid %d prev_state %ld */
+       (void)va_arg(*args, int);
+       (void)va_arg(*args, int);
+       (void)va_arg(*args, long);
+       __rq = va_arg(*args, typeof(__rq));
+       prev = va_arg(*args, typeof(prev));
+       next = va_arg(*args, typeof(next));
+
+       tracing_record_cmdline(prev);
+
+       /*
+        * If tracer_switch_func only points to the local
+        * switch func, it still needs the ptr passed to it.
+        */
+       sched_switch_func(probe_data, __rq, prev, next);
+}
+
 static void
-wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr)
+wakeup_func(void *private, void *__rq, struct task_struct *wakee, struct
+                       task_struct *curr)
 {
-       struct trace_array *tr = ctx_trace;
+       struct trace_array **ptr = private;
+       struct trace_array *tr = *ptr;
        struct trace_array_cpu *data;
        unsigned long flags;
        long disabled;
@@ -67,35 +100,29 @@ wakeup_func(void *__rq, struct task_struct *wakee, struct task_struct *curr)
        local_irq_restore(flags);
 }
 
-void
-ftrace_ctx_switch(void *__rq, struct task_struct *prev,
-                 struct task_struct *next)
+static notrace void
+wake_up_callback(void *probe_data, void *call_data,
+                const char *format, va_list *args)
 {
-       if (unlikely(atomic_read(&trace_record_cmdline_enabled)))
-               tracing_record_cmdline(prev);
+       struct task_struct *curr;
+       struct task_struct *task;
+       struct rq *__rq;
 
-       /*
-        * If tracer_switch_func only points to the local
-        * switch func, it still needs the ptr passed to it.
-        */
-       ctx_switch_func(__rq, prev, next);
+       if (likely(!tracer_enabled))
+               return;
 
-       /*
-        * Chain to the wakeup tracer (this is a NOP if disabled):
-        */
-       wakeup_sched_switch(prev, next);
-}
+       /* Skip pid %d state %ld */
+       (void)va_arg(*args, int);
+       (void)va_arg(*args, long);
+       /* now get the meat: "rq %p task %p rq->curr %p" */
+       __rq = va_arg(*args, typeof(__rq));
+       task = va_arg(*args, typeof(task));
+       curr = va_arg(*args, typeof(curr));
 
-void
-ftrace_wake_up_task(void *__rq, struct task_struct *wakee,
-                   struct task_struct *curr)
-{
-       wakeup_func(__rq, wakee, curr);
+       tracing_record_cmdline(task);
+       tracing_record_cmdline(curr);
 
-       /*
-        * Chain to the wakeup tracer (this is a NOP if disabled):
-        */
-       wakeup_sched_wakeup(wakee, curr);
+       wakeup_func(probe_data, __rq, task, curr);
 }
 
 void
@@ -132,15 +159,95 @@ static void sched_switch_reset(struct trace_array *tr)
                tracing_reset(tr->data[cpu]);
 }
 
+static int tracing_sched_register(void)
+{
+       int ret;
+
+       ret = marker_probe_register("kernel_sched_wakeup",
+                       "pid %d state %ld ## rq %p task %p rq->curr %p",
+                       wake_up_callback,
+                       &ctx_trace);
+       if (ret) {
+               pr_info("wakeup trace: Couldn't add marker"
+                       " probe to kernel_sched_wakeup\n");
+               return ret;
+       }
+
+       ret = marker_probe_register("kernel_sched_wakeup_new",
+                       "pid %d state %ld ## rq %p task %p rq->curr %p",
+                       wake_up_callback,
+                       &ctx_trace);
+       if (ret) {
+               pr_info("wakeup trace: Couldn't add marker"
+                       " probe to kernel_sched_wakeup_new\n");
+               goto fail_deprobe;
+       }
+
+       ret = marker_probe_register("kernel_sched_schedule",
+               "prev_pid %d next_pid %d prev_state %ld "
+               "## rq %p prev %p next %p",
+               sched_switch_callback,
+               &ctx_trace);
+       if (ret) {
+               pr_info("sched trace: Couldn't add marker"
+                       " probe to kernel_sched_schedule\n");
+               goto fail_deprobe_wake_new;
+       }
+
+       return ret;
+fail_deprobe_wake_new:
+       marker_probe_unregister("kernel_sched_wakeup_new",
+                               wake_up_callback,
+                               &ctx_trace);
+fail_deprobe:
+       marker_probe_unregister("kernel_sched_wakeup",
+                               wake_up_callback,
+                               &ctx_trace);
+       return ret;
+}
+
+static void tracing_sched_unregister(void)
+{
+       marker_probe_unregister("kernel_sched_schedule",
+                               sched_switch_callback,
+                               &ctx_trace);
+       marker_probe_unregister("kernel_sched_wakeup_new",
+                               wake_up_callback,
+                               &ctx_trace);
+       marker_probe_unregister("kernel_sched_wakeup",
+                               wake_up_callback,
+                               &ctx_trace);
+}
+
+void tracing_start_sched_switch(void)
+{
+       long ref;
+
+       ref = atomic_inc_return(&sched_ref);
+       if (ref == 1)
+               tracing_sched_register();
+}
+
+void tracing_stop_sched_switch(void)
+{
+       long ref;
+
+       ref = atomic_dec_and_test(&sched_ref);
+       if (ref)
+               tracing_sched_unregister();
+}
+
 static void start_sched_trace(struct trace_array *tr)
 {
        sched_switch_reset(tr);
        atomic_inc(&trace_record_cmdline_enabled);
        tracer_enabled = 1;
+       tracing_start_sched_switch();
 }
 
 static void stop_sched_trace(struct trace_array *tr)
 {
+       tracing_stop_sched_switch();
        atomic_dec(&trace_record_cmdline_enabled);
        tracer_enabled = 0;
 }
@@ -181,6 +288,14 @@ static struct tracer sched_switch_trace __read_mostly =
 
 __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);

diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 5948011..5d2fb48 100644 (file)
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -15,6 +15,7 @@
 #include <linux/kallsyms.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
+#include <linux/marker.h>
 
 #include "trace.h"
 
@@ -44,11 +45,13 @@ static int report_latency(cycle_t delta)
        return 1;
 }
 
-void
-wakeup_sched_switch(struct task_struct *prev, struct task_struct *next)
+static void notrace
+wakeup_sched_switch(void *private, void *rq, struct task_struct *prev,
+       struct task_struct *next)
 {
        unsigned long latency = 0, t0 = 0, t1 = 0;
-       struct trace_array *tr = wakeup_trace;
+       struct trace_array **ptr = private;
+       struct trace_array *tr = *ptr;
        struct trace_array_cpu *data;
        cycle_t T0, T1, delta;
        unsigned long flags;
@@ -113,6 +116,31 @@ out:
        atomic_dec(&tr->data[cpu]->disabled);
 }
 
+static notrace void
+sched_switch_callback(void *probe_data, void *call_data,
+                     const char *format, va_list *args)
+{
+       struct task_struct *prev;
+       struct task_struct *next;
+       struct rq *__rq;
+
+       /* skip prev_pid %d next_pid %d prev_state %ld */
+       (void)va_arg(*args, int);
+       (void)va_arg(*args, int);
+       (void)va_arg(*args, long);
+       __rq = va_arg(*args, typeof(__rq));
+       prev = va_arg(*args, typeof(prev));
+       next = va_arg(*args, typeof(next));
+
+       tracing_record_cmdline(prev);
+
+       /*
+        * If tracer_switch_func only points to the local
+        * switch func, it still needs the ptr passed to it.
+        */
+       wakeup_sched_switch(probe_data, __rq, prev, next);
+}
+
 static void __wakeup_reset(struct trace_array *tr)
 {
        struct trace_array_cpu *data;
@@ -188,19 +216,68 @@ out:
        atomic_dec(&tr->data[cpu]->disabled);
 }
 
-void wakeup_sched_wakeup(struct task_struct *wakee, struct task_struct *curr)
+static notrace void
+wake_up_callback(void *probe_data, void *call_data,
+                const char *format, va_list *args)
 {
+       struct trace_array **ptr = probe_data;
+       struct trace_array *tr = *ptr;
+       struct task_struct *curr;
+       struct task_struct *task;
+       struct rq *__rq;
+
        if (likely(!tracer_enabled))
                return;
 
+       /* Skip pid %d state %ld */
+       (void)va_arg(*args, int);
+       (void)va_arg(*args, long);
+       /* now get the meat: "rq %p task %p rq->curr %p" */
+       __rq = va_arg(*args, typeof(__rq));
+       task = va_arg(*args, typeof(task));
+       curr = va_arg(*args, typeof(curr));
+
+       tracing_record_cmdline(task);
        tracing_record_cmdline(curr);
-       tracing_record_cmdline(wakee);
 
-       wakeup_check_start(wakeup_trace, wakee, curr);
+       wakeup_check_start(tr, task, curr);
 }
 
 static void start_wakeup_tracer(struct trace_array *tr)
 {
+       int ret;
+
+       ret = marker_probe_register("kernel_sched_wakeup",
+                       "pid %d state %ld ## rq %p task %p rq->curr %p",
+                       wake_up_callback,
+                       &wakeup_trace);
+       if (ret) {
+               pr_info("wakeup trace: Couldn't add marker"
+                       " probe to kernel_sched_wakeup\n");
+               return;
+       }
+
+       ret = marker_probe_register("kernel_sched_wakeup_new",
+                       "pid %d state %ld ## rq %p task %p rq->curr %p",
+                       wake_up_callback,
+                       &wakeup_trace);
+       if (ret) {
+               pr_info("wakeup trace: Couldn't add marker"
+                       " probe to kernel_sched_wakeup_new\n");
+               goto fail_deprobe;
+       }
+
+       ret = marker_probe_register("kernel_sched_schedule",
+               "prev_pid %d next_pid %d prev_state %ld "
+               "## rq %p prev %p next %p",
+               sched_switch_callback,
+               &wakeup_trace);
+       if (ret) {
+               pr_info("sched trace: Couldn't add marker"
+                       " probe to kernel_sched_schedule\n");
+               goto fail_deprobe_wake_new;
+       }
+
        wakeup_reset(tr);
 
        /*
@@ -215,11 +292,28 @@ static void start_wakeup_tracer(struct trace_array *tr)
        tracer_enabled = 1;
 
        return;
+fail_deprobe_wake_new:
+       marker_probe_unregister("kernel_sched_wakeup_new",
+                               wake_up_callback,
+                               &wakeup_trace);
+fail_deprobe:
+       marker_probe_unregister("kernel_sched_wakeup",
+                               wake_up_callback,
+                               &wakeup_trace);
 }
 
 static void stop_wakeup_tracer(struct trace_array *tr)
 {
        tracer_enabled = 0;
+       marker_probe_unregister("kernel_sched_schedule",
+                               sched_switch_callback,
+                               &wakeup_trace);
+       marker_probe_unregister("kernel_sched_wakeup_new",
+                               wake_up_callback,
+                               &wakeup_trace);
+       marker_probe_unregister("kernel_sched_wakeup",
+                               wake_up_callback,
+                               &wakeup_trace);
 }
 
 static void wakeup_tracer_init(struct trace_array *tr)