Re: [RFC][Patch v12 1/2] mm: page_reporting: core infrastructure

Nitesh Narayan Lal
2019-08-13T10:43:05Z

On 8/13/19 6:34 AM, David Hildenbrand wrote:
>>>>> +static int process_free_page(struct page *page,
>>>>> + struct page_reporting_config *phconf, int count)
>>>>> +{
>>>>> + int mt, order, ret = 0;
[...]
>>>>> +/**
>>>>> + * zone_reporting_init - For each zone initializes the page reporting fields
>>>>> + * and allocates the respective bitmap.
>>>>> + *
>>>>> + * This function returns 0 on successful initialization, -ENOMEM otherwise.
>>>>> + */
>>>>> +static int zone_reporting_init(void)
>>>>> +{
>>>>> + struct zone *zone;
>>>>> + int ret;
>>>>> +
>>>>> + for_each_populated_zone(zone) {
>>>>> +#ifdef CONFIG_ZONE_DEVICE
>>>>> + /* we can not report pages which are not in the buddy */
>>>>> + if (zone_idx(zone) == ZONE_DEVICE)
>>>>> + continue;
>>>>> +#endif
>>>> I'm pretty sure this isn't needed since I don't think the ZONE_DEVICE
>>>> zone will be considered "populated".
>>>>
>>> I think you are right (although it's confusing, we will have present
>>> sections part of a zone but the zone has no present_pages - screams like
>>> a re factoring - leftover from ZONE_DEVICE introduction).
>>
>> I think in that case it is safe to have this check here.
>> What do you guys suggest?
> If it's not needed, I'd say drop it (eventually add a comment).

Comment to mention that we do not expect a zone with non-buddy page to be
initialized here?

>
>
--
Thanks
Nitesh