From 1d7503b5dccf2b95babca050e4960e10d2633f2b Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Mon, 8 Dec 2008 11:59:52 +0100 Subject: [PATCH] oprofile: remove nr_available_slots() This function is no longer available after the port to the new ring buffer. Its removal can lead to incomplete sampling sequences since IBS samples and backtraces are transfered in multiple samples. Due to a full buffer, samples could be lost any time. The userspace daemon has to live with such incomplete sampling sequences as long as the data within one sample is consistent. This will be fixed by changing the internal buffer data there all data of one IBS sample or a backtrace is packed in a single ring buffer entry. This is possible since the new ring buffer supports variable data size. Signed-off-by: Robert Richter --- drivers/oprofile/cpu_buffer.c | 34 ---------------------------------- 1 file changed, 34 deletions(-) diff --git a/drivers/oprofile/cpu_buffer.c b/drivers/oprofile/cpu_buffer.c index eb280ec96e24..7f7fc958297a 100644 --- a/drivers/oprofile/cpu_buffer.c +++ b/drivers/oprofile/cpu_buffer.c @@ -145,18 +145,6 @@ void end_cpu_work(void) flush_scheduled_work(); } -/* compute number of available slots in cpu_buffer queue */ -static unsigned long nr_available_slots(struct oprofile_cpu_buffer const *b) -{ - unsigned long head = b->head_pos; - unsigned long tail = b->tail_pos; - - if (tail > head) - return (tail - head) - 1; - - return tail + (b->buffer_size - head) - 1; -} - static inline void add_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc, unsigned long event) @@ -206,11 +194,6 @@ static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc, return 0; } - if (nr_available_slots(cpu_buf) < 3) { - cpu_buf->sample_lost_overflow++; - return 0; - } - is_kernel = !!is_kernel; task = current; @@ -233,11 +216,6 @@ static int log_sample(struct oprofile_cpu_buffer *cpu_buf, unsigned long pc, static int oprofile_begin_trace(struct oprofile_cpu_buffer *cpu_buf) { - if (nr_available_slots(cpu_buf) < 4) { - cpu_buf->sample_lost_overflow++; - return 0; - } - add_code(cpu_buf, CPU_TRACE_BEGIN); cpu_buf->tracing = 1; return 1; @@ -291,12 +269,6 @@ void oprofile_add_ibs_sample(struct pt_regs * const regs, cpu_buf->sample_received++; - if (nr_available_slots(cpu_buf) < MAX_IBS_SAMPLE_SIZE) { - /* we can't backtrace since we lost the source of this event */ - cpu_buf->sample_lost_overflow++; - return; - } - /* notice a switch from user->kernel or vice versa */ if (cpu_buf->last_is_kernel != is_kernel) { cpu_buf->last_is_kernel = is_kernel; @@ -342,12 +314,6 @@ void oprofile_add_trace(unsigned long pc) if (!cpu_buf->tracing) return; - if (nr_available_slots(cpu_buf) < 1) { - cpu_buf->tracing = 0; - cpu_buf->sample_lost_overflow++; - return; - } - /* * broken frame can give an eip with the same value as an * escape code, abort the trace if we get it