linux-kernel - [tip: perf/core] perf tools: Avoid a malloc() for array events

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Message-ID: <157355749440.29376.10975700265435116588.tip-bot2@tip-bot2>
Date:   Tue, 12 Nov 2019 11:18:14 -0000
From:   "tip-bot2 for Ian Rogers" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Ian Rogers <irogers@...gle.com>, Jiri Olsa <jolsa@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jin Yao <yao.jin@...ux.intel.com>,
        John Garry <john.garry@...wei.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Mark Rutland <mark.rutland@....com>,
        Martin KaFai Lau <kafai@...com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Song Liu <songliubraving@...com>,
        Stephane Eranian <eranian@...gle.com>,
        Yonghong Song <yhs@...com>, bpf@...r.kernel.org,
        clang-built-linux@...glegroups.com, netdev@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        linux-kernel@...r.kernel.org
Subject: [tip: perf/core] perf tools: Avoid a malloc() for array events

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     826100a7ce9a659b42140710ebe789d710799048
Gitweb:        https://git.kernel.org/tip/826100a7ce9a659b42140710ebe789d710799048
Author:        Ian Rogers <irogers@...gle.com>
AuthorDate:    Tue, 22 Oct 2019 17:53:33 -07:00
Committer:     Arnaldo Carvalho de Melo <acme@...hat.com>
CommitterDate: Wed, 06 Nov 2019 15:43:05 -03:00

perf tools: Avoid a malloc() for array events

Use realloc() rather than malloc()+memcpy() to possibly avoid a memory
allocation when appending array elements.

Signed-off-by: Ian Rogers <irogers@...gle.com>
Acked-by: Jiri Olsa <jolsa@...nel.org>
Cc: Adrian Hunter <adrian.hunter@...el.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Jin Yao <yao.jin@...ux.intel.com>
Cc: John Garry <john.garry@...wei.com>
Cc: Kan Liang <kan.liang@...ux.intel.com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Martin KaFai Lau <kafai@...com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Song Liu <songliubraving@...com>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Yonghong Song <yhs@...com>
Cc: bpf@...r.kernel.org
Cc: clang-built-linux@...glegroups.com
Cc: netdev@...r.kernel.org
Link: http://lore.kernel.org/lkml/20191023005337.196160-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/parse-events.y | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
index 5863acb..ffa1a1b 100644
--- a/tools/perf/util/parse-events.y
+++ b/tools/perf/util/parse-events.y
@@ -689,14 +689,12 @@ array_terms ',' array_term
 	struct parse_events_array new_array;
 
 	new_array.nr_ranges = $1.nr_ranges + $3.nr_ranges;
-	new_array.ranges = malloc(sizeof(new_array.ranges[0]) *
-				  new_array.nr_ranges);
+	new_array.ranges = realloc($1.ranges,
+				sizeof(new_array.ranges[0]) *
+				new_array.nr_ranges);
 	ABORT_ON(!new_array.ranges);
-	memcpy(&new_array.ranges[0], $1.ranges,
-	       $1.nr_ranges * sizeof(new_array.ranges[0]));
 	memcpy(&new_array.ranges[$1.nr_ranges], $3.ranges,
 	       $3.nr_ranges * sizeof(new_array.ranges[0]));
-	free($1.ranges);
 	free($3.ranges);
 	$$ = new_array;
 }