Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous

From	Xishi Qiu <qiuxishi@huawei.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous
Date	2016-02-15 11:10 +0100
Message-ID	<r2ogq-7VA-17@gated-at.bofh.it> (permalink)
References	(1 earlier) <qYlqO-4PS-17@gated-at.bofh.it> <qYCL1-18W-21@gated-at.bofh.it> <qYRgZ-2zl-1@gated-at.bofh.it> <r226d-1mT-1@gated-at.bofh.it> <r2hoB-34W-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 2016/2/15 10:42, Joonsoo Kim wrote:

>>
>> I have a question about the zone continuity. because hole exists at
>> arbitrary position in a page block. Therefore, only pageblock_pf_to_page()
>> is insufficiency, whether pageblock aligned pfn or not , the pfn_valid_within()
>> is necessary.
>>
>> eh: 120M-122M is a range of page block, but the 120.5M-121.5M is holes, only by
>> pageblock_pfn_to_page() to conclude in the result is inaccurate
> 
> contiguous may be misleading word. It doesn't represent there are no
> hole. It only represents that all pageblocks within zone span belong to
> corresponding zone and validity of all pageblock aligned pfn is
> checked. So, if it is set, we can safely call pfn_to_page() for pageblock
> aligned pfn in that zone without checking pfn_valid().
> 
> Thanks.
> 

Hi Joonsoo,

So "contiguous" here only means that struct page is exist, and don't care whether
the memory is exist, right?

Thanks,
Xishi Qiu

> 
> .
>

Thread

Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page()  when zone is contiguous zhong jiang <zhongjiang@huawei.com> - 2016-02-14 11:30 +0100
  Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page()  when zone is contiguous Joonsoo Kim <iamjoonsoo.kim@lge.com> - 2016-02-15 03:50 +0100
    Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page()  when zone is contiguous Xishi Qiu <qiuxishi@huawei.com> - 2016-02-15 11:10 +0100
      Re: [PATCH v2 3/3] mm/compaction: speed up pageblock_pfn_to_page()  when zone is contiguous Joonsoo Kim <js1304@gmail.com> - 2016-02-15 15:30 +0100

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