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Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  doc: mmiotrace.txt, buffer size control change
  trace: mmiotrace to the tracer menu in Kconfig
  mmiotrace: count events lost due to not recording
This commit is contained in:
Linus Torvalds
2009-02-17 14:29:15 -08:00
parent 35010334aa f9aa28adfc
commit f8effd1a4a
4 changed files with 37 additions and 30 deletions
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23
kernel/trace/Kconfig
View File

@@ -302,4 +302,27 @@ config FTRACE_STARTUP_TEST
functioning properly. It will do tests on all the configured
tracers of ftrace.
config MMIOTRACE
bool "Memory mapped IO tracing"
depends on HAVE_MMIOTRACE_SUPPORT && DEBUG_KERNEL && PCI
select TRACING
help
Mmiotrace traces Memory Mapped I/O access and is meant for
debugging and reverse engineering. It is called from the ioremap
implementation and works via page faults. Tracing is disabled by
default and can be enabled at run-time.
See Documentation/tracers/mmiotrace.txt.
If you are not helping to develop drivers, say N.
config MMIOTRACE_TEST
tristate "Test module for mmiotrace"
depends on MMIOTRACE && m
help
This is a dumb module for testing mmiotrace. It is very dangerous
as it will write garbage to IO memory starting at a given address.
However, it should be safe to use on e.g. unused portion of VRAM.
Say N, unless you absolutely know what you are doing.
endmenu

14
kernel/trace/trace_mmiotrace.c
View File

@@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/mmiotrace.h>
#include <linux/pci.h>
#include <asm/atomic.h>
#include "trace.h"
@@ -19,6 +20,7 @@ struct header_iter {
static struct trace_array *mmio_trace_array;
static bool overrun_detected;
static unsigned long prev_overruns;
static atomic_t dropped_count;
static void mmio_reset_data(struct trace_array *tr)
{
@@ -121,11 +123,11 @@ static void mmio_close(struct trace_iterator *iter)
static unsigned long count_overruns(struct trace_iterator *iter)
{
unsigned long cnt = 0;
unsigned long cnt = atomic_xchg(&dropped_count, 0);
unsigned long over = ring_buffer_overruns(iter->tr->buffer);
if (over > prev_overruns)
cnt = over - prev_overruns;
cnt += over - prev_overruns;
prev_overruns = over;
return cnt;
}
@@ -310,8 +312,10 @@ static void __trace_mmiotrace_rw(struct trace_array *tr,
event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
&irq_flags);
if (!event)
if (!event) {
atomic_inc(&dropped_count);
return;
}
entry = ring_buffer_event_data(event);
tracing_generic_entry_update(&entry->ent, 0, preempt_count());
entry->ent.type = TRACE_MMIO_RW;
@@ -338,8 +342,10 @@ static void __trace_mmiotrace_map(struct trace_array *tr,
event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry),
&irq_flags);
if (!event)
if (!event) {
atomic_inc(&dropped_count);
return;
}
entry = ring_buffer_event_data(event);
tracing_generic_entry_update(&entry->ent, 0, preempt_count());
entry->ent.type = TRACE_MMIO_MAP;