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SubjectRe: [PATCH v1] memory: tegra20: Add debug statistics
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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.

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