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ring-buffer: move calculation of event length 

The event length is calculated and passed in to rb_reserve_next_event
in two different locations. Having rb_reserve_next_event do the
calculations directly makes only one location to do the change and
causes the calculation to be inlined by gcc.

Before:
   text    data     bss     dec     hex filename
  16538      24      12   16574    40be kernel/trace/ring_buffer.o

After:
   text    data     bss     dec     hex filename
  16490      24      12   16526    408e kernel/trace/ring_buffer.o

[ Impact: smaller more efficient code ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2009-05-11 14:42:53 -04:00 committed by Steven Rostedt
parent 1cd8d73589
commit be957c447f
1 changed files with 9 additions and 5 deletions
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14
kernel/trace/ring_buffer.c
View File

@ -367,6 +367,9 @@ static inline int test_time_stamp(u64 delta)
#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE)
/* Max payload is BUF_PAGE_SIZE - header (8bytes) */
#define BUF_MAX_DATA_SIZE (BUF_PAGE_SIZE - (sizeof(u32) * 2))
int ring_buffer_print_page_header(struct trace_seq *s)
{
struct buffer_data_page field;
@ -1396,6 +1399,7 @@ rb_reserve_next_event(struct ring_buffer_per_cpu *cpu_buffer,
int commit = 0;
int nr_loops = 0;
length = rb_calculate_event_length(length);
again:
/*
* We allow for interrupts to reenter here and do a trace.
@ -1552,8 +1556,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long length)
if (atomic_read(&cpu_buffer->record_disabled))
goto out;
length = rb_calculate_event_length(length);
if (length > BUF_PAGE_SIZE)
if (length > BUF_MAX_DATA_SIZE)
goto out;
event = rb_reserve_next_event(cpu_buffer, length);
@ -1758,7 +1761,6 @@ int ring_buffer_write(struct ring_buffer *buffer,
{
struct ring_buffer_per_cpu *cpu_buffer;
struct ring_buffer_event *event;
unsigned long event_length;
void *body;
int ret = -EBUSY;
int cpu, resched;
@ -1781,8 +1783,10 @@ int ring_buffer_write(struct ring_buffer *buffer,
if (atomic_read(&cpu_buffer->record_disabled))
goto out;
event_length = rb_calculate_event_length(length);
event = rb_reserve_next_event(cpu_buffer, event_length);
if (length > BUF_MAX_DATA_SIZE)
goto out;
event = rb_reserve_next_event(cpu_buffer, length);
if (!event)
goto out;