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SubjectRe: [RFC PATCH v2 2/4] mm/__free_one_page: skip merge for order-0 page unless compaction failed
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On 03/22/2018 01:15 PM, Matthew Wilcox wrote:
> On Tue, Mar 20, 2018 at 10:11:01PM +0800, Aaron Lu wrote:
>>>> A new document file called "struct_page_filed" is added to explain
>>>> the newly reused field in "struct page".
>>>
>>> Sounds rather ad-hoc for a single field, I'd rather document it via
>>> comments.
>>
>> Dave would like to have a document to explain all those "struct page"
>> fields that are repurposed under different scenarios and this is the
>> very start of the document :-)
>>
>> I probably should have explained the intent of the document more.
>
> Dave and I are in agreement on "Shouldn't struct page be better documented".
> I came up with this a few weeks ago; never quite got round to turning it
> into a patch:
>
> +---+-----------+-----------+--------------+----------+--------+--------------+
> | B | slab | pagecache | tail 1 | anon | tail 1 | hugetlb |
> +===+===========+===========+==============+==========+========+==============+
> | 0 | flags |
> +---+ |
> | 4 | |
> +---+-----------+-----------+--------------+----------+--------+--------------+
> | 8 | s_mem | mapping | cmp_mapcount | anon_vma | defer | mapping |
> +---+ | +--------------+ | list | |
> |12 | | | | | | |
> +---+-----------+-----------+--------------+----------+ +--------------+
> |16 | freelist | index | | index |
> +---+ | | | (shifted) |
> |20 | | | | |
> +---+-----------+-------------------------------------+--------+--------------+
> |24 | counters | mapcount |
> +---+ +-----------+--------------+----------+--------+--------------+
> |28 | | refcount | | | | refcount |
> +---+-----------+-----------+--------------+----------+--------+--------------+
> |32 | next | lru | cmpd_head | | lru |
> +---+ | | +-------------------+ +
> |36 | | | | | |
> +---+-----------+ +--------------+-------------------+ +
> |40 | pages | | dtor / order | | |
> +---+-----------+ +--------------+-------------------+ +
> |44 | pobjects | | | | |
> +---+-----------+-----------+--------------+----------------------------------+
> |48 | slb_cache | private | | |
> +---+ | +--------------+----------------------------------+
> |52 | | | | |
> +---+-----------+-----------+--------------+----------------------------------+

Shouldn't the anon column also contain lru?

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