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[109.252.193.52]) by smtp.googlemail.com with ESMTPSA id n2sm277352lfu.274.2021.03.18.09.38.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 18 Mar 2021 09:38:59 -0700 (PDT) Subject: Re: [PATCH v1] memory: tegra20: Add debug statistics To: Krzysztof Kozlowski , Thierry Reding , Jonathan Hunter Cc: linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org References: <20210318115556.22792-1-digetx@gmail.com> <26ef74e0-67ff-77c4-1682-8f8261b71463@gmail.com> <9a634d0f-b12f-8b4d-8807-56182533fc3b@canonical.com> From: Dmitry Osipenko Message-ID: Date: Thu, 18 Mar 2021 19:38:59 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <9a634d0f-b12f-8b4d-8807-56182533fc3b@canonical.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 18.03.2021 19:20, Krzysztof Kozlowski пишет: > On 18/03/2021 17:18, Dmitry Osipenko wrote: >> 18.03.2021 18:23, Krzysztof Kozlowski пишет: >> >>>> + >>>> + /* collect memory controller utilization percent for each client */ >>>> + for (i = 0; i < mc->soc->num_clients; i += 2) { >>>> + client0 = &mc->soc->clients[i]; >>>> + client1 = &mc->soc->clients[i + 1]; >>>> + >>>> + if (i + 1 == mc->soc->num_clients) >>>> + client1 = NULL; >>>> + >>>> + tegra20_mc_stat_events(mc, client0, client1, >>>> + MC_STAT_CONTROL_FILTER_PRI_DISABLE, >>>> + MC_STAT_CONTROL_PRI_EVENT_HP, >>>> + MC_STAT_CONTROL_EVENT_QUALIFIED, >>>> + &stats[i + 0].events, >>>> + &stats[i + 1].events); >>>> + } >>>> + >>>> + /* collect more info from active clients */ >>>> + for (i = 0; i < mc->soc->num_clients; i++) { >>>> + clientb = mc->soc->num_clients; >>>> + >>>> + for (client0 = NULL; i < mc->soc->num_clients; i++) { >>>> + if (stats[i].events) { >>>> + client0 = &mc->soc->clients[i]; >>>> + clienta = i++; >>>> + break; >>>> + } >>>> + } >>> >>> Could all clients have 0 events ending with "clienta" being undefined? >>> "client0" would be non-NULL because of loop before. >> >> As per 6.8.5.3 of C99 standard, the declaration of a for-loop "is >> reached in the order of execution before the first evaluation of the >> controlling expression". >> >> http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf >> >>>> + >>>> + for (client1 = NULL; i < mc->soc->num_clients; i++) { >>>> + if (stats[i].events) { >>>> + client1 = &mc->soc->clients[i]; >>>> + clientb = i; >>>> + break; >>>> + } >>>> + } >>>> + >>>> + if (!client0 && !client1) >>>> + break; >> >> this means that both client0 and client1 are set t0 NULL here if all >> clients have 0 events. >> > > Yes, you're right. I missed the assignment client0=NULL in the for(). Good, thank you for the review! I'll prepare v2.