perf evlist: Fixup brown paper bag on "hint" for --mmap-pages cmdline arg

[deliverable/linux.git] / tools / perf / util / evlist.c

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 7e23dae54f1dbbc6e51b8373127e9ed8e68568c1..de7515dd683abcb8cad0c35c6e7f4659376f6999 100644 (file)
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -8,6 +8,7 @@
  */
 #include "util.h"
 #include <api/fs/debugfs.h>
+#include <api/fs/fs.h>
 #include <poll.h>
 #include "cpumap.h"
 #include "thread_map.h"
@@ -816,7 +817,15 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
                        perf_evlist__mmap_get(evlist, idx);
                }
 
-               if (__perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
+               /*
+                * The system_wide flag causes a selected event to be opened
+                * always without a pid.  Consequently it will never get a
+                * POLLHUP, but it is used for tracking in combination with
+                * other events, so it should not need to be polled anyway.
+                * Therefore don't add it for polling.
+                */
+               if (!evsel->system_wide &&
+                   __perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
                        perf_evlist__mmap_put(evlist, idx);
                        return -1;
                }
@@ -1475,6 +1484,28 @@ int perf_evlist__strerror_open(struct perf_evlist *evlist __maybe_unused,
        return 0;
 }
 
+int perf_evlist__strerror_mmap(struct perf_evlist *evlist, int err, char *buf, size_t size)
+{
+       char sbuf[STRERR_BUFSIZE], *emsg = strerror_r(err, sbuf, sizeof(sbuf));
+       int value;
+
+       switch (err) {
+       case EPERM:
+               sysctl__read_int("kernel/perf_event_mlock_kb", &value);
+               scnprintf(buf, size, "Error:\t%s.\n"
+                                    "Hint:\tCheck /proc/sys/kernel/perf_event_mlock_kb (%d kB) setting.\n"
+                                    "Hint:\tTried using %zd kB.\n"
+                                    "Hint:\tTry using a smaller -m/--mmap-pages value.",
+                                    emsg, value, evlist->mmap_len / 1024);
+               break;
+       default:
+               scnprintf(buf, size, "%s", emsg);
+               break;
+       }
+
+       return 0;
+}
+
 void perf_evlist__to_front(struct perf_evlist *evlist,
                           struct perf_evsel *move_evsel)
 {