From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753423AbbE0KIy (ORCPT ); Wed, 27 May 2015 06:08:54 -0400 Received: from terminus.zytor.com ([198.137.202.10]:33664 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750755AbbE0KIs (ORCPT ); Wed, 27 May 2015 06:08:48 -0400 Date: Wed, 27 May 2015 03:08:18 -0700 From: tip-bot for Alexander Shishkin Message-ID: Cc: paulus@samba.org, alexander.shishkin@linux.intel.com, torvalds@linux-foundation.org, mingo@kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org, hpa@zytor.com, tglx@linutronix.de Reply-To: hpa@zytor.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, mingo@kernel.org, peterz@infradead.org, torvalds@linux-foundation.org, alexander.shishkin@linux.intel.com, paulus@samba.org In-Reply-To: <1429622177-22843-5-git-send-email-alexander.shishkin@linux.intel.com> References: <1429622177-22843-5-git-send-email-alexander.shishkin@linux.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf/x86/intel/pt: Document pt_buffer_reset_offsets() Git-Commit-ID: 5b1dbd17c0dee679b154ce47f534677b7e0f7ad6 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 5b1dbd17c0dee679b154ce47f534677b7e0f7ad6 Gitweb: http://git.kernel.org/tip/5b1dbd17c0dee679b154ce47f534677b7e0f7ad6 Author: Alexander Shishkin AuthorDate: Tue, 21 Apr 2015 16:16:16 +0300 Committer: Ingo Molnar CommitDate: Wed, 27 May 2015 09:17:47 +0200 perf/x86/intel/pt: Document pt_buffer_reset_offsets() Currently, the description of pt_buffer_reset_offsets() lacks information about its calling constraints and ordering with regards to other buffer management functions. Add a clarification about when this function has to be called. Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: acme@infradead.org Cc: adrian.hunter@intel.com Cc: hpa@zytor.com Link: http://lkml.kernel.org/r/1429622177-22843-5-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_intel_pt.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_pt.c b/arch/x86/kernel/cpu/perf_event_intel_pt.c index b2746ea..40ba5e4 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_pt.c +++ b/arch/x86/kernel/cpu/perf_event_intel_pt.c @@ -705,7 +705,14 @@ static void pt_buffer_setup_topa_index(struct pt_buffer *buf) * @head: Write pointer (aux_head) from AUX buffer. * * Find the ToPA table and entry corresponding to given @head and set buffer's - * "current" pointers accordingly. + * "current" pointers accordingly. This is done after we have obtained the + * current aux_head position from a successful call to perf_aux_output_begin() + * to make sure the hardware is writing to the right place. + * + * This function modifies buf::{cur,cur_idx,output_off} that will be programmed + * into PT msrs when the tracing is enabled and buf::head and buf::data_size, + * which are used to determine INT and STOP markers' locations by a subsequent + * call to pt_buffer_reset_markers(). */ static void pt_buffer_reset_offsets(struct pt_buffer *buf, unsigned long head) {