perf hists: Resort after filtering hierarchy

In hierarchy mode, a filter can affect periods of entries in upper
hierarchy.  So it needs to resort the hists after filter.

For example, let's look at following example:

 Overhead      Command / Shared Object / Symbol
 ------------  --------------------------------
 30.00%        perf
    20.00%        perf
       10.00%        main
        5.00%        pr_debug
        5.00%        memcpy
    10.00%        [kernel.vmlinux]
        8.00%        memset
        2.00%        cpu_idle

If we apply simbol filter for 'mem' it should look like this

 13.00%        perf
     8.00%        [kernel.vmlinux]
        8.00%        memset
     5.00%        perf
        5.00%        memcpy
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1456326830-30456-8-git-send-email-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/hist.c

@@ -1666,9 +1666,47 @@ static void hists__filter_by_type(struct hists *hists, int type, filter_fn_t fil
 	}
 }
 
+static void resort_filtered_entry(struct rb_root *root, struct hist_entry *he)
+{
+	struct rb_node **p = &root->rb_node;
+	struct rb_node *parent = NULL;
+	struct hist_entry *iter;
+	struct rb_root new_root = RB_ROOT;
+	struct rb_node *nd;
+
+	while (*p != NULL) {
+		parent = *p;
+		iter = rb_entry(parent, struct hist_entry, rb_node);
+
+		if (hist_entry__sort(he, iter) > 0)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&he->rb_node, parent, p);
+	rb_insert_color(&he->rb_node, root);
+
+	if (he->leaf || he->filtered)
+		return;
+
+	nd = rb_first(&he->hroot_out);
+	while (nd) {
+		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
+
+		nd = rb_next(nd);
+		rb_erase(&h->rb_node, &he->hroot_out);
+
+		resort_filtered_entry(&new_root, h);
+	}
+
+	he->hroot_out = new_root;
+}
+
 static void hists__filter_hierarchy(struct hists *hists, int type, const void *arg)
 {
 	struct rb_node *nd;
+	struct rb_root new_root = RB_ROOT;
 
 	hists->stats.nr_non_filtered_samples = 0;
 
@@ -1712,6 +1750,22 @@ static void hists__filter_hierarchy(struct hists *hists, int type, const void *a
 			nd = __rb_hierarchy_next(&h->rb_node, HMD_FORCE_SIBLING);
 		}
 	}
+
+	/*
+	 * resort output after applying a new filter since filter in a lower
+	 * hierarchy can change periods in a upper hierarchy.
+	 */
+	nd = rb_first(&hists->entries);
+	while (nd) {
+		struct hist_entry *h = rb_entry(nd, struct hist_entry, rb_node);
+
+		nd = rb_next(nd);
+		rb_erase(&h->rb_node, &hists->entries);
+
+		resort_filtered_entry(&new_root, h);
+	}
+
+	hists->entries = new_root;
 }
 
 void hists__filter_by_thread(struct hists *hists)