[for-next][PATCH 1/8] tracing: Create a always_inlined __trace_buffer_lock_reserve()

From: Steven Rostedt
Date: Tue Nov 29 2016 - 10:09:37 EST


From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>

As Andi Kleen pointed out in the Link below, the trace events has quite a
bit of code execution. A lot of that happens to be calling functions, where
some of them should simply be inlined. One of these functions happens to be
trace_buffer_lock_reserve() which is also a global, but it is used
throughout the file it is defined in. Create a __trace_buffer_lock_reserve()
that is always inlined that the file can benefit from.

Link: http://lkml.kernel.org/r/20161121183700.GW26852@xxxxxxxxxxxxxxxxxx

Reported-by: Andi Kleen <andi@xxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace.c | 87 +++++++++++++++++++++++++++++-----------------------
1 file changed, 48 insertions(+), 39 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index edccdff8a36d..490533726b54 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -739,6 +739,31 @@ static inline void ftrace_trace_stack(struct trace_array *tr,

#endif

+static __always_inline void
+trace_event_setup(struct ring_buffer_event *event,
+ int type, unsigned long flags, int pc)
+{
+ struct trace_entry *ent = ring_buffer_event_data(event);
+
+ tracing_generic_entry_update(ent, flags, pc);
+ ent->type = type;
+}
+
+static __always_inline struct ring_buffer_event *
+__trace_buffer_lock_reserve(struct ring_buffer *buffer,
+ int type,
+ unsigned long len,
+ unsigned long flags, int pc)
+{
+ struct ring_buffer_event *event;
+
+ event = ring_buffer_lock_reserve(buffer, len);
+ if (event != NULL)
+ trace_event_setup(event, type, flags, pc);
+
+ return event;
+}
+
static void tracer_tracing_on(struct trace_array *tr)
{
if (tr->trace_buffer.buffer)
@@ -795,8 +820,8 @@ int __trace_puts(unsigned long ip, const char *str, int size)

local_save_flags(irq_flags);
buffer = global_trace.trace_buffer.buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
- irq_flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
+ irq_flags, pc);
if (!event)
return 0;

@@ -843,8 +868,8 @@ int __trace_bputs(unsigned long ip, const char *str)

local_save_flags(irq_flags);
buffer = global_trace.trace_buffer.buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
- irq_flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
+ irq_flags, pc);
if (!event)
return 0;

@@ -1913,29 +1938,13 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
}
EXPORT_SYMBOL_GPL(tracing_generic_entry_update);

-static __always_inline void
-trace_event_setup(struct ring_buffer_event *event,
- int type, unsigned long flags, int pc)
-{
- struct trace_entry *ent = ring_buffer_event_data(event);
-
- tracing_generic_entry_update(ent, flags, pc);
- ent->type = type;
-}
-
struct ring_buffer_event *
trace_buffer_lock_reserve(struct ring_buffer *buffer,
int type,
unsigned long len,
unsigned long flags, int pc)
{
- struct ring_buffer_event *event;
-
- event = ring_buffer_lock_reserve(buffer, len);
- if (event != NULL)
- trace_event_setup(event, type, flags, pc);
-
- return event;
+ return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
}

DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
@@ -2090,8 +2099,8 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
this_cpu_dec(trace_buffered_event_cnt);
}

- entry = trace_buffer_lock_reserve(*current_rb,
- type, len, flags, pc);
+ entry = __trace_buffer_lock_reserve(*current_rb,
+ type, len, flags, pc);
/*
* If tracing is off, but we have triggers enabled
* we still need to look at the event data. Use the temp_buffer
@@ -2100,8 +2109,8 @@ trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
*/
if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
*current_rb = temp_buffer;
- entry = trace_buffer_lock_reserve(*current_rb,
- type, len, flags, pc);
+ entry = __trace_buffer_lock_reserve(*current_rb,
+ type, len, flags, pc);
}
return entry;
}
@@ -2262,8 +2271,8 @@ trace_function(struct trace_array *tr,
struct ring_buffer_event *event;
struct ftrace_entry *entry;

- event = trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
- flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
+ flags, pc);
if (!event)
return;
entry = ring_buffer_event_data(event);
@@ -2342,8 +2351,8 @@ static void __ftrace_trace_stack(struct ring_buffer *buffer,

size *= sizeof(unsigned long);

- event = trace_buffer_lock_reserve(buffer, TRACE_STACK,
- sizeof(*entry) + size, flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
+ sizeof(*entry) + size, flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
@@ -2444,8 +2453,8 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)

__this_cpu_inc(user_stack_count);

- event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
- sizeof(*entry), flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
+ sizeof(*entry), flags, pc);
if (!event)
goto out_drop_count;
entry = ring_buffer_event_data(event);
@@ -2615,8 +2624,8 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
local_save_flags(flags);
size = sizeof(*entry) + sizeof(u32) * len;
buffer = tr->trace_buffer.buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
- flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+ flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
@@ -2671,8 +2680,8 @@ __trace_array_vprintk(struct ring_buffer *buffer,

local_save_flags(flags);
size = sizeof(*entry) + len + 1;
- event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
- flags, pc);
+ event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+ flags, pc);
if (!event)
goto out;
entry = ring_buffer_event_data(event);
@@ -5732,8 +5741,8 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
local_save_flags(irq_flags);
size = sizeof(*entry) + cnt + 2; /* possible \n added */
buffer = tr->trace_buffer.buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
- irq_flags, preempt_count());
+ event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+ irq_flags, preempt_count());
if (!event) {
/* Ring buffer disabled, return as if not open for write */
written = -EBADF;
@@ -5810,8 +5819,8 @@ tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
local_save_flags(irq_flags);
size = sizeof(*entry) + cnt;
buffer = tr->trace_buffer.buffer;
- event = trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
- irq_flags, preempt_count());
+ event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
+ irq_flags, preempt_count());
if (!event) {
/* Ring buffer disabled, return as if not open for write */
written = -EBADF;
--
2.10.2