[tip:perf/core] perf callchain: Add enum match_result for match_chain()

tip-bot for Namhyung Kim
2016-02-20T11:40:51Z

Commit-ID: 2d713b809d89a3d10c6a85162bf7cce0468e45d9
Gitweb: http://git.kernel.org/tip/2d713b809d89a3d10c6a85162bf7cce0468e45d9
Author: Namhyung Kim <namhyung@kernel.org>
AuthorDate: Tue, 16 Feb 2016 23:08:22 +0900
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 19 Feb 2016 19:14:20 -0300

perf callchain: Add enum match_result for match_chain()

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 a82ea6f..dab2c1f 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,