linux-kernel - [PATCH 2/2] perf map: optimize maps__fixup

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Date:   Tue, 07 Aug 2018 12:09:05 +0300
From:   Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:     linux-kernel@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...hat.com>
Subject: [PATCH 2/2] perf map: optimize maps__fixup_overlappings()

This function splits and removes overlapping areas.

Maps in tree are ordered by start address thus we could find
first overlap and stop if next map does not overlap.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
 tools/perf/util/map.c |   21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 89ac5b5dc218..9b3f4d244ad4 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -675,20 +675,35 @@ static void __map_groups__insert(struct map_groups *mg, struct map *map)
 static int maps__fixup_overlappings(struct maps *maps, struct map *map, FILE *fp)
 {
 	struct rb_root *root;
-	struct rb_node *next;
+	struct rb_node *next, *first;
 	int err = 0;
 
 	down_write(&maps->lock);
 
 	root = &maps->entries;
-	next = rb_first(root);
 
+	/* find first where end > map->start, same as find_vma() */
+	next = root->rb_node;
+	first = NULL;
+	while (next) {
+		struct map *pos = rb_entry(next, struct map, rb_node);
+
+		if (pos->end > map->start) {
+			first = next;
+			if (pos->start <= map->start)
+				break;
+			next = next->rb_left;
+		} else
+			next = next->rb_right;
+	}
+
+	next = first;
 	while (next) {
 		struct map *pos = rb_entry(next, struct map, rb_node);
 		next = rb_next(&pos->rb_node);
 
 		if (!map__overlap(pos, map))
-			continue;
+			break;
 
 		if (verbose >= 2) {