perf session: Move unmap code to reader__mmap

Move the unmapping code to reader__mmap(), so that the mmap code is
located together.

Move the head/file_offset computation to reader__mmap(), so all the
offset computation is located together and in one place only.

Suggested-by: Jiri Olsa <jolsa@kernel.org>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Riccardo Mancini <rickyman7@gmail.com>
Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Tested-by: Riccardo Mancini <rickyman7@gmail.com>
Acked-by: Namhyung Kim <namhyung@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/f1c5e17cfa1ecfe912d10b411be203b55d148bc7.1634113027.git.alexey.v.bayduraev@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 1abe870..4cbe663 100644 (file)
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2192,13 +2192,9 @@ 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;
@@ -2229,6 +2225,7 @@ 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;
@@ -2240,6 +2237,15 @@ 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) {
@@ -2261,9 +2267,8 @@ 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;
 
@@ -2284,17 +2289,8 @@ more:
        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;
-       }
 
        size = event->header.size;