From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757876Ab3HMGxu (ORCPT ); Tue, 13 Aug 2013 02:53:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:60515 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756455Ab3HMGdR (ORCPT ); Tue, 13 Aug 2013 02:33:17 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Z Lam , Vaibhav Nagarnaik , David Sharp , Alexander Z Lam , Steven Rostedt Subject: [ 25/60] tracing: Fix reset of time stamps during trace_clock changes Date: Mon, 12 Aug 2013 23:33:52 -0700 Message-Id: <20130813063335.440826205@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.3.825.g36032ce.dirty In-Reply-To: <20130813063331.950321483@linuxfoundation.org> References: <20130813063331.950321483@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Z Lam commit 9457158bbc0ee04ecef76862d73eecd8076e9c7b upstream. Fixed two issues with changing the timestamp clock with trace_clock: - The global buffer was reset on instance clock changes. Change this to pass the correct per-instance buffer - ftrace_now() is used to set buf->time_start in tracing_reset_online_cpus(). This was incorrect because ftrace_now() used the global buffer's clock to return the current time. Change this to use buffer_ftrace_now() which returns the current time for the correct per-instance buffer. Also removed tracing_reset_current() because it is not used anywhere Link: http://lkml.kernel.org/r/1375493777-17261-2-git-send-email-azl@google.com Signed-off-by: Alexander Z Lam Cc: Vaibhav Nagarnaik Cc: David Sharp Cc: Alexander Z Lam Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -232,20 +232,25 @@ int filter_current_check_discard(struct } EXPORT_SYMBOL_GPL(filter_current_check_discard); -cycle_t ftrace_now(int cpu) +cycle_t buffer_ftrace_now(struct trace_buffer *buf, int cpu) { u64 ts; /* Early boot up does not have a buffer yet */ - if (!global_trace.trace_buffer.buffer) + if (!buf->buffer) return trace_clock_local(); - ts = ring_buffer_time_stamp(global_trace.trace_buffer.buffer, cpu); - ring_buffer_normalize_time_stamp(global_trace.trace_buffer.buffer, cpu, &ts); + ts = ring_buffer_time_stamp(buf->buffer, cpu); + ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts); return ts; } +cycle_t ftrace_now(int cpu) +{ + return buffer_ftrace_now(&global_trace.trace_buffer, cpu); +} + /** * tracing_is_enabled - Show if global_trace has been disabled * @@ -1194,7 +1199,7 @@ void tracing_reset_online_cpus(struct tr /* Make sure all commits have finished */ synchronize_sched(); - buf->time_start = ftrace_now(buf->cpu); + buf->time_start = buffer_ftrace_now(buf, buf->cpu); for_each_online_cpu(cpu) ring_buffer_reset_cpu(buffer, cpu); @@ -1202,11 +1207,6 @@ void tracing_reset_online_cpus(struct tr ring_buffer_record_enable(buffer); } -void tracing_reset_current(int cpu) -{ - tracing_reset(&global_trace.trace_buffer, cpu); -} - /* Must have trace_types_lock held */ void tracing_reset_all_online_cpus(void) { @@ -4647,12 +4647,12 @@ static ssize_t tracing_clock_write(struc * New clock may not be consistent with the previous clock. * Reset the buffer so that it doesn't have incomparable timestamps. */ - tracing_reset_online_cpus(&global_trace.trace_buffer); + tracing_reset_online_cpus(&tr->trace_buffer); #ifdef CONFIG_TRACER_MAX_TRACE if (tr->flags & TRACE_ARRAY_FL_GLOBAL && tr->max_buffer.buffer) ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func); - tracing_reset_online_cpus(&global_trace.max_buffer); + tracing_reset_online_cpus(&tr->max_buffer); #endif mutex_unlock(&trace_types_lock);