perf session: Flag if the event stream is entirely in memory

Flag if the event stream is a file that has been mmapped in one go.

This is useful, for example, if a tool needs to keep an event for later
reference.  If the new flag is set, a pointer to the event can be
retained, otherwise the event must be copied.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1405332185-4050-28-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 11 insertions, 1 deletions

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index c2f4ca917469..eac14ce0ae8d 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1297,8 +1297,10 @@ int __perf_session__process_events(struct perf_session *session,
         ui_progress__init(&prog, file_size, "Processing events...");
 
         mmap_size = MMAP_SIZE;
-        if (mmap_size > file_size)
+        if (mmap_size > file_size) {
                 mmap_size = file_size;
+                session->one_mmap = true;
+        }
 
         memset(mmaps, 0, sizeof(mmaps));
 
@@ -1320,6 +1322,10 @@ remap:
         mmaps[map_idx] = buf;
         map_idx = (map_idx + 1) & (ARRAY_SIZE(mmaps) - 1);
         file_pos = file_offset + head;
+        if (session->one_mmap) {
+                session->one_mmap_addr = buf;
+                session->one_mmap_offset = file_offset;
+        }
 
 more:
         event = fetch_mmaped_event(session, head, mmap_size, buf);
@@ -1365,6 +1371,7 @@ out_err:
         ui_progress__finish();
         perf_session__warn_about_errors(session, tool);
         perf_session_free_sample_buffers(session);
+        session->one_mmap = false;
         return err;
 }
 
diff --git a/tools/perf/util/session.h b/tools/perf/util/session.h
index 3140f8ae6148..0321013bd9fd 100644
--- a/tools/perf/util/session.h
+++ b/tools/perf/util/session.h
@@ -36,6 +36,9 @@ struct perf_session {
         struct trace_event      tevent;
         struct events_stats     stats;
         bool                    repipe;
+        bool                    one_mmap;
+        void                    *one_mmap_addr;
+        u64                     one_mmap_offset;
         struct ordered_samples  ordered_samples;
         struct perf_data_file   *file;
 };