linux-kernel - [PATCH v3 5/8] perf session: Move unmap code to reader_

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Date:   Thu,  7 Oct 2021 13:25:40 +0300
From:   Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Antonov <alexander.antonov@...ux.intel.com>,
        Alexei Budankov <abudankov@...wei.com>,
        Riccardo Mancini <rickyman7@...il.com>
Subject: [PATCH v3 5/8] perf session: Move unmap code to reader__mmap

Moving unmapping code into reader__mmap, so the mmap code
is located together. Moving head/file_offset computation into
reader__mmap function, so all the offset computation is
located together and in one place only.

Suggested-by: Jiri Olsa <jolsa@...nel.org>
Acked-by: Namhyung Kim <namhyung@...il.com>
Reviewed-by: Riccardo Mancini <rickyman7@...il.com>
Tested-by: Riccardo Mancini <rickyman7@...il.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>
---
 tools/perf/util/session.c | 30 +++++++++++++-----------------
 1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 36faa2d598b2..6289fcafdc86 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2187,13 +2187,9 @@ static int
 reader__init(struct reader *rd, bool *one_mmap)
 {
 	u64 data_size = rd->data_size;
-	u64 page_offset;
 	char **mmaps = rd->mmaps;
 
-	page_offset = page_size * (rd->data_offset / page_size);
-	rd->file_offset = page_offset;
-	rd->head = rd->data_offset - page_offset;
-
+	rd->head = rd->data_offset;
 	data_size += rd->data_offset;
 
 	rd->mmap_size = MMAP_SIZE;
@@ -2224,6 +2220,7 @@ reader__mmap(struct reader *rd, struct perf_session *session)
 {
 	int mmap_prot, mmap_flags;
 	char *buf, **mmaps = rd->mmaps;
+	u64 page_offset;
 
 	mmap_prot  = PROT_READ;
 	mmap_flags = MAP_SHARED;
@@ -2235,6 +2232,15 @@ reader__mmap(struct reader *rd, struct perf_session *session)
 		mmap_flags = MAP_PRIVATE;
 	}
 
+	if (mmaps[rd->mmap_idx]) {
+		munmap(mmaps[rd->mmap_idx], rd->mmap_size);
+		mmaps[rd->mmap_idx] = NULL;
+	}
+
+	page_offset = page_size * (rd->head / page_size);
+	rd->file_offset += page_offset;
+	rd->head -= page_offset;
+
 	buf = mmap(NULL, rd->mmap_size, mmap_prot, mmap_flags, rd->fd,
 		   rd->file_offset);
 	if (buf == MAP_FAILED) {
@@ -2256,9 +2262,8 @@ static int
 reader__process_events(struct reader *rd, struct perf_session *session,
 		       struct ui_progress *prog)
 {
-	u64 page_offset, size;
+	u64 size;
 	int err = 0;
-	char **mmaps = rd->mmaps;
 	union perf_event *event;
 	s64 skip;
 
@@ -2277,17 +2282,8 @@ reader__process_events(struct reader *rd, struct perf_session *session,
 	if (IS_ERR(event))
 		return PTR_ERR(event);
 
-	if (!event) {
-		if (mmaps[rd->mmap_idx]) {
-			munmap(mmaps[rd->mmap_idx], rd->mmap_size);
-			mmaps[rd->mmap_idx] = NULL;
-		}
-
-		page_offset = page_size * (rd->head / page_size);
-		rd->file_offset += page_offset;
-		rd->head -= page_offset;
+	if (!event)
 		goto remap;
-	}
 
 	session->active_decomp = &rd->decomp_data;
 	size = event->header.size;
-- 
2.19.0