From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A49E6C433B4 for ; Tue, 6 Apr 2021 12:45:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7357B6124C for ; Tue, 6 Apr 2021 12:45:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344151AbhDFMp4 (ORCPT ); Tue, 6 Apr 2021 08:45:56 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:2767 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241986AbhDFMps (ORCPT ); Tue, 6 Apr 2021 08:45:48 -0400 Received: from fraeml709-chm.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4FF6X04Jycz681X8; Tue, 6 Apr 2021 20:38:40 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml709-chm.china.huawei.com (10.206.15.37) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Tue, 6 Apr 2021 14:45:38 +0200 Received: from [10.210.166.136] (10.210.166.136) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Tue, 6 Apr 2021 13:45:36 +0100 Subject: Re: [PATCH v2 2/6] perf test: Handle metric reuse in pmu-events parsing test To: Jiri Olsa CC: , , , , , , , , , , , , , , , , References: <1616668398-144648-1-git-send-email-john.garry@huawei.com> <1616668398-144648-3-git-send-email-john.garry@huawei.com> From: John Garry Message-ID: Date: Tue, 6 Apr 2021 13:43:09 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.210.166.136] X-ClientProxiedBy: lhreml711-chm.china.huawei.com (10.201.108.62) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/04/2021 13:17, Jiri Olsa wrote: >>>> + ref = &metric->metric_ref; >>>> + ref->metric_name = pe->metric_name; >>>> + ref->metric_expr = pe->metric_expr; >>>> + list_add_tail(&metric->list, compound_list); >>>> + >>>> + rc = expr__find_other(pe->metric_expr, NULL, pctx, 0); >> Hi Jirka, >> >>> so this might add new items to pctx->ids, I think you need >>> to restart the iteration as we do it in __resolve_metric >>> otherwise you could miss some new keys >> I thought that I was doing this. Indeed, this code is very much like >> __resolve_metric();) >> >> So expr__find_other() may add a new item to pctx->ids, and we always iterate >> again, and try to lookup any pmu_events, *, above. If none exist, then we > hm, I don't see that.. so, what you do is: > > hashmap__for_each_entry_safe((&pctx->ids) ....) { > > rc = expr__find_other(pe->metric_expr, NULL, pctx, 0); > } > > and what I think we need to do is: > > hashmap__for_each_entry_safe((&pctx->ids) ....) { > > rc = expr__find_other(pe->metric_expr, NULL, pctx, 0); > > break; > } > > each time you resolve another metric, you need to restart > the pctx->ids iteration, because there will be new items, > and we are in the middle of it Sure, but we will restart anyway. Regardless of this, I don't think what I am doing is safe, i.e. adding new items in the middle of the iter, so I will change in the way you suggest. Thanks, John