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    SubjectRE: [PATCH perf/core 00/22] perf refcnt debugger API and fixes
    Date
    >From: Namhyung Kim [mailto:namhyung@kernel.org]
    >
    >Hi Arnaldo and Masami,
    >
    >On Wed, Dec 09, 2015 at 10:41:38AM -0300, Arnaldo Carvalho de Melo wrote:
    >> Em Wed, Dec 09, 2015 at 11:10:48AM +0900, Masami Hiramatsu escreveu:
    >> > In this series I've also tried to fix some object leaks in perf top
    >> > and perf stat.
    >> > After applying this series, this reduced (not vanished) to 1/5.
    >> > ----
    >> > # ./perf top --stdio
    >> > q
    >> > exiting.
    >> > REFCNT: BUG: Unreclaimed objects found.
    >> > REFCNT: Total 866 objects are not reclaimed.
    >> > "dso" leaks 213 objects
    >> > "map" leaks 624 objects
    >> > "comm_str" leaks 12 objects
    >> > "thread" leaks 9 objects
    >> > "map_groups" leaks 8 objects
    >> > To see all backtraces, rerun with -v option
    >> > ----
    >> >
    >> > Actually, I'm still not able to fix all of the bugs. It seems that
    >> > hists has a bug that hists__delete_entries doesn't delete all the
    >> > entries because some entries are on hists->entries but others on
    >> > hists->entries_in. And I'm not so sure about hists.c.
    >> > Arnaldo, would you have any idea for this bug?
    >>
    >> I'll will audit the hists code, its all about collecting new entries
    >> into an rbtree to then move the last batch for merging with the
    >> previous, decayed ones while continuing to process a new batch in
    >> another thread.
    >
    >Right. After processing is done, hist entries are in both of
    >hists->entries and hists->entries_in (or hists->entries_collapsed).
    >So I guess perf report does not have leaks on hists.
    >
    >But for perf top, it's possible to have half-processed entries which
    >are only in hists->entries_in. Eventually they will go to the
    >hists->entries and get freed but they cannot be deleted by current
    >hists__delete_entries(). If we really care deleting all of those
    >half-processed entries, how about this?
    >

    Nice! I've applied below patch on the top of my series and
    checked that no leak is detected. :)

    You can add my acked-by and tested-by. :)

    Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
    Tested-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

    Thanks!

    >
    >
    >diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
    >index fd179a068df7..08396a7fea23 100644
    >--- a/tools/perf/util/hist.c
    >+++ b/tools/perf/util/hist.c
    >@@ -270,6 +270,8 @@ static void hists__delete_entry(struct hists *hists, struct hist_entry *he)
    >
    > if (sort__need_collapse)
    > rb_erase(&he->rb_node_in, &hists->entries_collapsed);
    >+ else
    >+ rb_erase(&he->rb_node_in, hists->entries_in);
    >
    > --hists->nr_entries;
    > if (!he->filtered)
    >@@ -1589,11 +1591,33 @@ int __hists__init(struct hists *hists)
    > return 0;
    > }
    >
    >+static void hists__delete_remaining_entries(struct rb_root *root)
    >+{
    >+ struct rb_node *node;
    >+ struct hist_entry *he;
    >+
    >+ while (!RB_EMPTY_ROOT(root)) {
    >+ node = rb_first(root);
    >+ rb_erase(node, root);
    >+
    >+ he = rb_entry(node, struct hist_entry, rb_node_in);
    >+ hist_entry__delete(he);
    >+ }
    >+}
    >+
    >+static void hists__delete_all_entries(struct hists *hists)
    >+{
    >+ hists__delete_entries(hists);
    >+ hists__delete_remaining_entries(&hists->entries_in_array[0]);
    >+ hists__delete_remaining_entries(&hists->entries_in_array[1]);
    >+ hists__delete_remaining_entries(&hists->entries_collapsed);
    >+}
    >+
    > static void hists_evsel__exit(struct perf_evsel *evsel)
    > {
    > struct hists *hists = evsel__hists(evsel);
    >
    >- hists__delete_entries(hists);
    >+ hists__delete_all_entries(hists);
    > }
    >
    > static int hists_evsel__init(struct perf_evsel *evsel)
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