Re: [RFC PATCH v3 5/8] mm: page_isolation: check specified range for unmovable pages during isolation.

[Zi Yan]

On 14 Jan 2022, at 8:38, David Hildenbrand wrote:

> On 05.01.22 22:47, Zi Yan wrote:
>> From: Zi Yan <ziy@xxxxxxxxxx>
>>
>> Enable set_migratetype_isolate() to check specified sub-range for
>> unmovable pages during isolation. Page isolation is done
>> at max(MAX_ORDER_NR_PAEGS, pageblock_nr_pages) granularity, but not all
>> pages within that granularity are intended to be isolated. For example,
>> alloc_contig_range(), which uses page isolation, allows ranges without
>> alignment. This commit makes unmovable page check only look for
>> interesting pages, so that page isolation can succeed for any
>> non-overlapping ranges.
>
> Are you handling if we start checking in the middle of a compound page
> and actually have to lookup the head to figure out if movable or not?
>

Yes. has_unmovable_pages() has that check already.


>>
>> has_unmovable_pages() is moved to mm/page_isolation.c since it is only
>> used by page isolation.
>
> Please move that into a separate patch upfront, makes this patch much
> easier to review.

Sure. Will do.

Thanks.

--
Best Regards,
Yan, Zi

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