From: Dmitry Osipenko <digetx@gmail.com>
To: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
Thierry Reding <thierry.reding@gmail.com>,
Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org
Subject: Re: [PATCH v1] memory: tegra20: Add debug statistics
Date: Thu, 18 Mar 2021 19:38:59 +0300 [thread overview]
Message-ID: <c696c57d-7bc3-a089-43a2-c3eec1412895@gmail.com> (raw)
In-Reply-To: <9a634d0f-b12f-8b4d-8807-56182533fc3b@canonical.com>
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.
prev parent reply other threads:[~2021-03-18 16:39 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 11:55 [PATCH v1] memory: tegra20: Add debug statistics Dmitry Osipenko
2021-03-18 15:23 ` Krzysztof Kozlowski
2021-03-18 16:18 ` Dmitry Osipenko
2021-03-18 16:20 ` Krzysztof Kozlowski
2021-03-18 16:38 ` Dmitry Osipenko [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=c696c57d-7bc3-a089-43a2-c3eec1412895@gmail.com \
--to=digetx@gmail.com \
--cc=jonathanh@nvidia.com \
--cc=krzysztof.kozlowski@canonical.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tegra@vger.kernel.org \
--cc=thierry.reding@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).