From 43a15386c4faf913f7d70a47748c266d6210cd6e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Weisbecker?= Date: Sun, 21 Sep 2008 20:16:30 +0200 Subject: [PATCH] tracing/ftrace: replace none tracer by nop tracer Replace "none" tracer by the recently created "nop" tracer. Both are pretty similar except that nop accepts TRACE_PRINT or TRACE_SPECIAL entries. And as a consequence, changing the size of the ring buffer now requires that tracing has already been disabled. Signed-off-by: Frederic Weisbecker Cc: Steven Rostedt Cc: Steven Noonan Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 49 ++++++++-------------------------------- kernel/trace/trace.h | 2 ++ kernel/trace/trace_nop.c | 7 +----- 3 files changed, 12 insertions(+), 46 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index eee1fd964898..f2ef72fa3f17 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -142,24 +142,6 @@ static DECLARE_WAIT_QUEUE_HEAD(trace_wait); /* trace_flags holds iter_ctrl options */ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT; -static notrace void no_trace_init(struct trace_array *tr) -{ - int cpu; - - ftrace_function_enabled = 0; - if(tr->ctrl) - for_each_online_cpu(cpu) - tracing_reset(tr->data[cpu]); - tracer_enabled = 0; -} - -/* dummy trace to disable tracing */ -static struct tracer no_tracer __read_mostly = { - .name = "none", - .init = no_trace_init -}; - - /** * trace_wake_up - wake up tasks waiting for trace input * @@ -962,7 +944,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3) long disabled; int cpu; - if (tracing_disabled || current_trace == &no_tracer || !tr->ctrl) + if (tracing_disabled || !tr->ctrl) return; local_irq_save(flags); @@ -2795,6 +2777,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, unsigned long val; char buf[64]; int i, ret; + struct trace_array *tr = filp->private_data; if (cnt >= sizeof(buf)) return -EINVAL; @@ -2814,9 +2797,9 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, mutex_lock(&trace_types_lock); - if (current_trace != &no_tracer) { + if (tr->ctrl) { cnt = -EBUSY; - pr_info("ftrace: set current_tracer to none" + pr_info("ftrace: please disable tracing" " before modifying buffer size\n"); goto out; } @@ -2879,20 +2862,6 @@ tracing_entries_write(struct file *filp, const char __user *ubuf, return cnt; } -static int tracing_open_mark(struct inode *inode, struct file *filp) -{ - int ret; - - ret = tracing_open_generic(inode, filp); - if (ret) - return ret; - - if (current_trace == &no_tracer) - return -ENODEV; - - return 0; -} - static int mark_printk(const char *fmt, ...) { int ret; @@ -2911,7 +2880,7 @@ tracing_mark_write(struct file *filp, const char __user *ubuf, char *end; struct trace_array *tr = &global_trace; - if (current_trace == &no_tracer || !tr->ctrl || tracing_disabled) + if (!tr->ctrl || tracing_disabled) return -EINVAL; if (cnt > TRACE_BUF_SIZE) @@ -2971,7 +2940,7 @@ static struct file_operations tracing_entries_fops = { }; static struct file_operations tracing_mark_fops = { - .open = tracing_open_mark, + .open = tracing_open_generic, .write = tracing_mark_write, }; @@ -3123,7 +3092,7 @@ int trace_vprintk(unsigned long ip, const char *fmt, va_list args) long disabled; int cpu, len = 0, write, written = 0; - if (current_trace == &no_tracer || !tr->ctrl || tracing_disabled) + if (!tr->ctrl || tracing_disabled) return 0; local_irq_save(flags); @@ -3539,8 +3508,8 @@ __init static int tracer_alloc_buffers(void) trace_init_cmdlines(); - register_tracer(&no_tracer); - current_trace = &no_tracer; + register_tracer(&nop_trace); + current_trace = &nop_trace; /* All seems OK, enable tracing */ global_trace.ctrl = tracer_enabled; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index c8c687088b4d..cb2c3fb7dd54 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -369,4 +369,6 @@ enum trace_iterator_flags { TRACE_ITER_PRINTK = 0x400, }; +extern struct tracer nop_trace; + #endif /* _LINUX_KERNEL_TRACE_H */ diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c index 9fb02c17ad0c..16c9ba060bab 100644 --- a/kernel/trace/trace_nop.c +++ b/kernel/trace/trace_nop.c @@ -51,7 +51,7 @@ static void nop_trace_ctrl_update(struct trace_array *tr) stop_nop_trace(tr); } -static struct tracer nop_trace __read_mostly = +struct tracer nop_trace __read_mostly = { .name = "nop", .init = nop_trace_init, @@ -62,8 +62,3 @@ static struct tracer nop_trace __read_mostly = #endif }; -__init static int init_nop_trace(void) -{ - return register_tracer(&nop_trace); -} -device_initcall(init_nop_trace);