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Groups > linux.kernel > #1338552

[PATCH 18/22] perf callchain: Add enum match_result for match_chain()

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject [PATCH 18/22] perf callchain: Add enum match_result for match_chain()
Date 2016-02-19 23:50 +0100
Message-ID <r4226-3Wq-19@gated-at.bofh.it> (permalink)
References <r4226-3Wq-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Namhyung Kim <namhyung@kernel.org>

The append_chain() might return either result of match_chain() or other
(error) code.  But match_chain() can return any value in s64 type so
it's hard to check the error case.  Add new enum match_result and make
match_chain() return non-negative values only so that we can check the
error cases.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1455631723-17345-5-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/callchain.c | 52 +++++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 18 deletions(-)

diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index a82ea6f6fc0f..dab2c1f1e86b 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -475,16 +475,32 @@ add_child(struct callchain_node *parent,
 	return new;
 }
 
-static s64 match_chain(struct callchain_cursor_node *node,
-		      struct callchain_list *cnode)
+enum match_result {
+	MATCH_ERROR  = -1,
+	MATCH_EQ,
+	MATCH_LT,
+	MATCH_GT,
+};
+
+static enum match_result match_chain(struct callchain_cursor_node *node,
+				     struct callchain_list *cnode)
 {
 	struct symbol *sym = node->sym;
+	u64 left, right;
 
 	if (cnode->ms.sym && sym &&
-	    callchain_param.key == CCKEY_FUNCTION)
-		return cnode->ms.sym->start - sym->start;
-	else
-		return cnode->ip - node->ip;
+	    callchain_param.key == CCKEY_FUNCTION) {
+		left = cnode->ms.sym->start;
+		right = sym->start;
+	} else {
+		left = cnode->ip;
+		right = node->ip;
+	}
+
+	if (left == right)
+		return MATCH_EQ;
+
+	return left > right ? MATCH_GT : MATCH_LT;
 }
 
 /*
@@ -549,7 +565,7 @@ split_add_child(struct callchain_node *parent,
 		cnode = list_first_entry(&first->val, struct callchain_list,
 					 list);
 
-		if (match_chain(node, cnode) < 0)
+		if (match_chain(node, cnode) == MATCH_LT)
 			pp = &p->rb_left;
 		else
 			pp = &p->rb_right;
@@ -562,7 +578,7 @@ split_add_child(struct callchain_node *parent,
 	}
 }
 
-static int
+static enum match_result
 append_chain(struct callchain_node *root,
 	     struct callchain_cursor *cursor,
 	     u64 period);
@@ -583,17 +599,17 @@ append_chain_children(struct callchain_node *root,
 
 	/* lookup in childrens */
 	while (*p) {
-		s64 ret;
+		enum match_result ret;
 
 		parent = *p;
 		rnode = rb_entry(parent, struct callchain_node, rb_node_in);
 
 		/* If at least first entry matches, rely to children */
 		ret = append_chain(rnode, cursor, period);
-		if (ret == 0)
+		if (ret == MATCH_EQ)
 			goto inc_children_hit;
 
-		if (ret < 0)
+		if (ret == MATCH_LT)
 			p = &parent->rb_left;
 		else
 			p = &parent->rb_right;
@@ -611,7 +627,7 @@ inc_children_hit:
 	root->children_count++;
 }
 
-static int
+static enum match_result
 append_chain(struct callchain_node *root,
 	     struct callchain_cursor *cursor,
 	     u64 period)
@@ -620,7 +636,7 @@ append_chain(struct callchain_node *root,
 	u64 start = cursor->pos;
 	bool found = false;
 	u64 matches;
-	int cmp = 0;
+	enum match_result cmp = MATCH_ERROR;
 
 	/*
 	 * Lookup in the current node
@@ -636,7 +652,7 @@ append_chain(struct callchain_node *root,
 			break;
 
 		cmp = match_chain(node, cnode);
-		if (cmp)
+		if (cmp != MATCH_EQ)
 			break;
 
 		found = true;
@@ -646,7 +662,7 @@ append_chain(struct callchain_node *root,
 
 	/* matches not, relay no the parent */
 	if (!found) {
-		WARN_ONCE(!cmp, "Chain comparison error\n");
+		WARN_ONCE(cmp == MATCH_ERROR, "Chain comparison error\n");
 		return cmp;
 	}
 
@@ -655,20 +671,20 @@ append_chain(struct callchain_node *root,
 	/* we match only a part of the node. Split it and add the new chain */
 	if (matches < root->val_nr) {
 		split_add_child(root, cursor, cnode, start, matches, period);
-		return 0;
+		return MATCH_EQ;
 	}
 
 	/* we match 100% of the path, increment the hit */
 	if (matches == root->val_nr && cursor->pos == cursor->nr) {
 		root->hit += period;
 		root->count++;
-		return 0;
+		return MATCH_EQ;
 	}
 
 	/* We match the node and still have a part remaining */
 	append_chain_children(root, cursor, period);
 
-	return 0;
+	return MATCH_EQ;
 }
 
 int callchain_append(struct callchain_root *root,
-- 
2.5.0

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Thread

[GIT PULL 00/22] perf/core improvements and fixes Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 09/22] perf tools: Create config_term_names array Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 11/22] perf tools: Rename and move pmu_event_name to get_config_name Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 18/22] perf callchain: Add enum match_result for match_chain() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 03/22] perf evlist: Handle -EINVAL for sample_freq > max_sample_rate in strerror_open() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 16/22] perf callchain: Check return value of add_child() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 05/22] perf test: Reduce the sample_freq for the 'object code reading' test Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 13/22] perf tools: Enable config raw and numeric events Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 17/22] perf callchain: Check return value of fill_node() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 12/22] perf tools: Introduce opt_event_config nonterminal Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 01/22] perf evlist: Reference count the cpu and thread maps at set_maps() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 04/22] perf tests: Use perf_evlist__strerror_open() to provide hints about max_freq Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 21/22] perf hists: Return error from hists__collapse_resort() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 19/22] perf callchain: Check return value of split_add_child() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 06/22] perf stat: Handled scaled == -1 case for counters Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 02/22] perf record: Add --all-user/--all-kernel options Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 22/22] perf report: Check error during report__collapse_hists() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 08/22] perf tools: Fix checking asprintf return value Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 07/22] perf bpf: Rename bpf_prog_priv__clear() to clear_prog_priv() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 20/22] perf callchain: Check return value of append_chain_children() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 15/22] perf hists browser: Fix percentage update on key press Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  [PATCH 14/22] perf tools: Enable config and setting names for legacy cache events Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-02-19 23:50 +0100
  Re: [GIT PULL 00/22] perf/core improvements and fixes Ingo Molnar <mingo@kernel.org> - 2016-02-20 12:00 +0100

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