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 | | | | | +---+-----------+-----------+--------------+----------------------------------+
