From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AC83217C79; Fri, 7 Mar 2025 02:01:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741312875; cv=none; b=qTV9xD30Mw7mpi2sohvYj+n5OcNWn2Ue9TG7ZFAy4l+OCRDpgk1nxjUklfBpNfKbrhN+O6RI0iFq+s3A/mJEtoFizdJLP4nwsxy7ftFzSsmoWw8DqeOlVYO0kuRgCNlCzaYYRKhkdGrsJAL81A9OBiZjMUxTmLzrcILcnKZLtSU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741312875; c=relaxed/simple; bh=zgU5y4KBtoIrMungqTdL46dfjARdNggTQr4L8B7Nl7s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=awefm4Wrgpw8Cb1349tPCnYqCPAg/9vXA5P7OpRwGz4n1lXOMXGqLcTDHAzBPGazIqpBZHuut3Tl9A2bcqRzamPYv2gEsLKoENxd4fOpFVhl/apvk9yiKaRJzMqMtUnaRl70XjQUe5uYVmXuZxCY6cxotrcWW+7SQkzQAHguHH8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XoMsgtce; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XoMsgtce" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C33C8C4CEE0; Fri, 7 Mar 2025 02:01:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741312875; bh=zgU5y4KBtoIrMungqTdL46dfjARdNggTQr4L8B7Nl7s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XoMsgtceiM1XuPAbPlcP/eCAIfPK1qw9FzLEyP48MTgxb2lElLn4E8ctodVzNmVoD wANfLpGhRwFkb/alftaPU39ngmlXMKQ2MtCrNMGyfll8t89Om/qVr2R/8gFyg9My2m bKxRxSQWg01CphD2bijsRG0qoHu0uBI+R2GvHNeL0VW/QEk6ufsddJ1Nun985DruZc GRjsf06qI2MyCYxQmQHTAd3Z5wQQ5jzwHHr+qov7k4xfwppGRFuiGNTERJUexYoqxz hnfbo+ifXa5l32uGlblGXAeVvi9wRIawp6KyrwusA/Rpupm0MVfdNEgIpBnaju0smY 7B9ok1Qiniiiw== Date: Thu, 6 Mar 2025 18:01:13 -0800 From: Namhyung Kim To: Ian Rogers Cc: Arnaldo Carvalho de Melo , Kan Liang , Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org Subject: Re: [PATCH 2/2] perf report: Fix memory leaks in the hierarchy mode Message-ID: References: <20250306075147.195435-1-namhyung@kernel.org> <20250306075147.195435-2-namhyung@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Mar 06, 2025 at 09:07:00AM -0800, Namhyung Kim wrote: > Hi Ian, > > On Thu, Mar 06, 2025 at 08:55:05AM -0800, Ian Rogers wrote: > > On Wed, Mar 5, 2025 at 11:51 PM Namhyung Kim wrote: > > > > > > Ian told me that there are many memory leaks in the hierarchy mode. I > > > can easily reproduce it with the follwing command. > > > > > > $ make DEBUG=1 EXTRA_CFLAGS=-fsanitize=leak > > > > > > $ perf record --latency -g -- ./perf test -w thloop > > > > > > $ perf report -H --stdio > > > ... > > > Indirect leak of 168 byte(s) in 21 object(s) allocated from: > > > #0 0x7f3414c16c65 in malloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:75 > > > #1 0x55ed3602346e in map__get util/map.h:189 > > > #2 0x55ed36024cc4 in hist_entry__init util/hist.c:476 > > > #3 0x55ed36025208 in hist_entry__new util/hist.c:588 > > > #4 0x55ed36027c05 in hierarchy_insert_entry util/hist.c:1587 > > > #5 0x55ed36027e2e in hists__hierarchy_insert_entry util/hist.c:1638 > > > #6 0x55ed36027fa4 in hists__collapse_insert_entry util/hist.c:1685 > > > #7 0x55ed360283e8 in hists__collapse_resort util/hist.c:1776 > > > #8 0x55ed35de0323 in report__collapse_hists /home/namhyung/project/linux/tools/perf/builtin-report.c:735 > > > #9 0x55ed35de15b4 in __cmd_report /home/namhyung/project/linux/tools/perf/builtin-report.c:1119 > > > #10 0x55ed35de43dc in cmd_report /home/namhyung/project/linux/tools/perf/builtin-report.c:1867 > > > #11 0x55ed35e66767 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:351 > > > #12 0x55ed35e66a0e in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:404 > > > #13 0x55ed35e66b67 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:448 > > > #14 0x55ed35e66eb0 in main /home/namhyung/project/linux/tools/perf/perf.c:556 > > > #15 0x7f340ac33d67 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 > > > ... > > > > > > $ perf report -H --stdio 2>&1 | grep -c '^Indirect leak' > > > 93 > > > > > > I found that hist_entry__delete() missed to release child entries in the > > > hierarchy tree (hroot_{in,out}). It needs to iterate the child entries > > > and call hist_entry__delete() recursively. > > > > > > After this change: > > > > > > $ perf report -H --stdio 2>&1 | grep -c '^Indirect leak' > > > 0 > > > > > > Reported-by: Ian Rogers > > > Signed-off-by: Namhyung Kim > > > --- > > > tools/perf/util/hist.c | 9 +++++++++ > > > 1 file changed, 9 insertions(+) > > > > > > diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c > > > index fbf131aeae7ffe9b..bbc6a299b5106c3b 100644 > > > --- a/tools/perf/util/hist.c > > > +++ b/tools/perf/util/hist.c > > > @@ -1385,6 +1385,15 @@ void hist_entry__delete(struct hist_entry *he) > > > { > > > struct hist_entry_ops *ops = he->ops; > > > > > > + while (!RB_EMPTY_ROOT(&he->hroot_out.rb_root)) { > > > + struct rb_node *node = rb_first(&he->hroot_out.rb_root); > > > + struct hist_entry *child = rb_entry(node, struct hist_entry, rb_node); > > > + > > > + rb_erase_init(node, &he->hroot_out.rb_root); > > > + > > > + hist_entry__delete(child); > > > + } > > > > Thanks for the fix! A nit, iterating the rbtree of N nodes and calling > > erase on the first entry, an O(log N) operation, means this is a O(N * > > log N). rbtree.h has rbtree_postorder_for_each_entry_safe: > > https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/include/linux/rbtree.h?h=perf-tools-next#n81 > > ``` > > * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of > > * given type allowing the backing memory of @pos to be invalidated > > ``` > > which is O(N). I think this code would be better something like: > > ``` > > struct hist_entry *pos, *tmp; > > rbtree_postorder_for_each_entry_safe(pos, tmp, he->hroot_out.rb_root, rb_node) > > hist_entry__delete(pos); > > ``` > > Thanks for your review! I was wondering if there's something like this. > Will update with that. I found that the following comments: * Note, however, that it cannot handle other modifications that re-order the * rbtree it is iterating over. This includes calling rb_erase() on @pos, as * rb_erase() may rebalance the tree, causing us to miss some nodes. So I cannot use this here. Thanks, Namhyung