From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751658AbeCTGeA (ORCPT ); Tue, 20 Mar 2018 02:34:00 -0400 Received: from terminus.zytor.com ([198.137.202.136]:44781 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751455AbeCTGd4 (ORCPT ); Tue, 20 Mar 2018 02:33:56 -0400 Date: Mon, 19 Mar 2018 23:33:31 -0700 From: tip-bot for Yisheng Xie Message-ID: Cc: acme@redhat.com, kan.liang@linux.intel.com, tglx@linutronix.de, alexander.shishkin@linux.intel.com, peterz@infradead.org, mingo@kernel.org, jolsa@redhat.com, xieyisheng1@huawei.com, namhyung@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com Reply-To: kan.liang@linux.intel.com, acme@redhat.com, jolsa@redhat.com, mingo@kernel.org, peterz@infradead.org, alexander.shishkin@linux.intel.com, tglx@linutronix.de, linux-kernel@vger.kernel.org, namhyung@kernel.org, xieyisheng1@huawei.com, hpa@zytor.com In-Reply-To: <1520944274-37001-1-git-send-email-xieyisheng1@huawei.com> References: <1520944274-37001-1-git-send-email-xieyisheng1@huawei.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/core] perf mmap: Discard head in overwrite_rb_find_range() Git-Commit-ID: 699db111058798bcc9f92a93767062905a561bef 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: 699db111058798bcc9f92a93767062905a561bef Gitweb: https://git.kernel.org/tip/699db111058798bcc9f92a93767062905a561bef Author: Yisheng Xie AuthorDate: Tue, 13 Mar 2018 20:31:13 +0800 Committer: Arnaldo Carvalho de Melo CommitDate: Fri, 16 Mar 2018 16:33:05 -0300 perf mmap: Discard head in overwrite_rb_find_range() In overwrite mode, start will be set to head in perf_mmap__read_init(). Therefore, there is no need to set the start one more time in overwrite_rb_find_range() and *start can be used as head instead of passing head to overwrite_rb_find_range(). Signed-off-by: Yisheng Xie Reviewed-by: Kan Liang Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1520944274-37001-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/mmap.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c index 074c4fd3b67e..38ca3ffb9d61 100644 --- a/tools/perf/util/mmap.c +++ b/tools/perf/util/mmap.c @@ -199,19 +199,18 @@ int perf_mmap__mmap(struct perf_mmap *map, struct mmap_params *mp, int fd) return 0; } -static int overwrite_rb_find_range(void *buf, int mask, u64 head, u64 *start, u64 *end) +static int overwrite_rb_find_range(void *buf, int mask, u64 *start, u64 *end) { struct perf_event_header *pheader; - u64 evt_head = head; + u64 evt_head = *start; int size = mask + 1; - pr_debug2("overwrite_rb_find_range: buf=%p, head=%"PRIx64"\n", buf, head); - pheader = (struct perf_event_header *)(buf + (head & mask)); - *start = head; + pr_debug2("%s: buf=%p, start=%"PRIx64"\n", __func__, buf, *start); + pheader = (struct perf_event_header *)(buf + (*start & mask)); while (true) { - if (evt_head - head >= (unsigned int)size) { + if (evt_head - *start >= (unsigned int)size) { pr_debug("Finished reading overwrite ring buffer: rewind\n"); - if (evt_head - head > (unsigned int)size) + if (evt_head - *start > (unsigned int)size) evt_head -= pheader->size; *end = evt_head; return 0; @@ -262,7 +261,7 @@ int perf_mmap__read_init(struct perf_mmap *md) * Backward ring buffer is full. We still have a chance to read * most of data from it. */ - if (overwrite_rb_find_range(data, md->mask, head, &md->start, &md->end)) + if (overwrite_rb_find_range(data, md->mask, &md->start, &md->end)) return -EINVAL; }