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path: root/drivers/oprofile/cpu_buffer.c
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Diffstat (limited to 'drivers/oprofile/cpu_buffer.c')
-rw-r--r--drivers/oprofile/cpu_buffer.c139
1 files changed, 75 insertions, 64 deletions
diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c
index 400f7fcffdb..e859d23cfc5 100644
--- a/drivers/oprofile/cpu_buffer.c
+++ b/drivers/oprofile/cpu_buffer.c
@@ -212,6 +212,59 @@ unsigned long op_cpu_buffer_entries(int cpu)
+ ring_buffer_entries_cpu(op_ring_buffer_write, cpu);
}
+static int
+op_add_code(struct oprofile_cpu_buffer *cpu_buf, unsigned long backtrace,
+ int is_kernel, struct task_struct *task)
+{
+ struct op_entry entry;
+ struct op_sample *sample;
+ unsigned long flags;
+ int size;
+
+ flags = 0;
+
+ if (backtrace)
+ flags |= TRACE_BEGIN;
+
+ /* notice a switch from user->kernel or vice versa */
+ is_kernel = !!is_kernel;
+ if (cpu_buf->last_is_kernel != is_kernel) {
+ cpu_buf->last_is_kernel = is_kernel;
+ flags |= KERNEL_CTX_SWITCH;
+ if (is_kernel)
+ flags |= IS_KERNEL;
+ }
+
+ /* notice a task switch */
+ if (cpu_buf->last_task != task) {
+ cpu_buf->last_task = task;
+ flags |= USER_CTX_SWITCH;
+ }
+
+ if (!flags)
+ /* nothing to do */
+ return 0;
+
+ if (flags & USER_CTX_SWITCH)
+ size = 1;
+ else
+ size = 0;
+
+ sample = op_cpu_buffer_write_reserve(&entry, size);
+ if (!sample)
+ return -ENOMEM;
+
+ sample->eip = ESCAPE_CODE;
+ sample->event = flags;
+
+ if (size)
+ sample->data[0] = (unsigned long)task;
+
+ op_cpu_buffer_write_commit(&entry);
+
+ return 0;
+}
+
static inline int
op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
unsigned long pc, unsigned long event)
@@ -229,26 +282,18 @@ op_add_sample(struct oprofile_cpu_buffer *cpu_buf,
return op_cpu_buffer_write_commit(&entry);
}
-static inline int
-add_code(struct oprofile_cpu_buffer *buffer, unsigned long value)
-{
- return op_add_sample(buffer, ESCAPE_CODE, value);
-}
-
-/* This must be safe from any context. It's safe writing here
- * because of the head/tail separation of the writer and reader
- * of the CPU buffer.
+/*
+ * This must be safe from any context.
*
* is_kernel is needed because on some architectures you cannot
* tell if you are in kernel or user space simply by looking at
* pc. We tag this in the buffer by generating kernel enter/exit
* events whenever is_kernel changes
*/
-static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
- int is_kernel, unsigned long event)
+static int
+log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
+ unsigned long backtrace, int is_kernel, unsigned long event)
{
- struct task_struct *task;
-
cpu_buf->sample_received++;
if (pc == ESCAPE_CODE) {
@@ -256,23 +301,8 @@ static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc,
return 0;
}
- is_kernel = !!is_kernel;
-
- task = current;
-
- /* notice a switch from user->kernel or vice versa */
- if (cpu_buf->last_is_kernel != is_kernel) {
- cpu_buf->last_is_kernel = is_kernel;
- if (add_code(cpu_buf, is_kernel))
- goto fail;
- }
-
- /* notice a task switch */
- if (cpu_buf->last_task != task) {
- cpu_buf->last_task = task;
- if (add_code(cpu_buf, (unsigned long)task))
- goto fail;
- }
+ if (op_add_code(cpu_buf, backtrace, is_kernel, current))
+ goto fail;
if (op_add_sample(cpu_buf, pc, event))
goto fail;
@@ -286,7 +316,6 @@ fail:
static inline void oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf)
{
- add_code(cpu_buf, CPU_TRACE_BEGIN);
cpu_buf->tracing = 1;
}
@@ -300,21 +329,21 @@ __oprofile_add_ext_sample(unsigned long pc, struct pt_regs * const regs,
unsigned long event, int is_kernel)
{
struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(cpu_buffer);
-
- if (!oprofile_backtrace_depth) {
- log_sample(cpu_buf, pc, is_kernel, event);
- return;
- }
-
- oprofile_begin_trace(cpu_buf);
+ unsigned long backtrace = oprofile_backtrace_depth;
/*
* if log_sample() fail we can't backtrace since we lost the
* source of this event
*/
- if (log_sample(cpu_buf, pc, is_kernel, event))
- oprofile_ops.backtrace(regs, oprofile_backtrace_depth);
+ if (!log_sample(cpu_buf, pc, backtrace, is_kernel, event))
+ /* failed */
+ return;
+ if (!backtrace)
+ return;
+
+ oprofile_begin_trace(cpu_buf);
+ oprofile_ops.backtrace(regs, backtrace);
oprofile_end_trace(cpu_buf);
}
@@ -339,29 +368,14 @@ void oprofile_add_ibs_sample(struct pt_regs * const regs,
{
int is_kernel = !user_mode(regs);
struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(cpu_buffer);
- struct task_struct *task;
int fail = 0;
cpu_buf->sample_received++;
- /* notice a switch from user->kernel or vice versa */
- if (cpu_buf->last_is_kernel != is_kernel) {
- if (add_code(cpu_buf, is_kernel))
- goto fail;
- cpu_buf->last_is_kernel = is_kernel;
- }
+ /* backtraces disabled for ibs */
+ fail = fail || op_add_code(cpu_buf, 0, is_kernel, current);
- /* notice a task switch */
- if (!is_kernel) {
- task = current;
- if (cpu_buf->last_task != task) {
- if (add_code(cpu_buf, (unsigned long)task))
- goto fail;
- cpu_buf->last_task = task;
- }
- }
-
- fail = fail || add_code(cpu_buf, ibs_code);
+ fail = fail || op_add_sample(cpu_buf, ESCAPE_CODE, ibs_code);
fail = fail || op_add_sample(cpu_buf, ibs_sample[0], ibs_sample[1]);
fail = fail || op_add_sample(cpu_buf, ibs_sample[2], ibs_sample[3]);
fail = fail || op_add_sample(cpu_buf, ibs_sample[4], ibs_sample[5]);
@@ -372,11 +386,8 @@ void oprofile_add_ibs_sample(struct pt_regs * const regs,
fail = fail || op_add_sample(cpu_buf, ibs_sample[10], ibs_sample[11]);
}
- if (!fail)
- return;
-
-fail:
- cpu_buf->sample_lost_overflow++;
+ if (fail)
+ cpu_buf->sample_lost_overflow++;
}
#endif
@@ -384,7 +395,7 @@ fail:
void oprofile_add_pc(unsigned long pc, int is_kernel, unsigned long event)
{
struct oprofile_cpu_buffer *cpu_buf = &__get_cpu_var(cpu_buffer);
- log_sample(cpu_buf, pc, is_kernel, event);
+ log_sample(cpu_buf, pc, 0, is_kernel, event);
}
void oprofile_add_trace(unsigned long pc)