On Thu, 10 Dec 2020, Vlastimil Babka wrote: > The page allocator expects that page->mapping is NULL for a page being freed. > SLAB and SLUB use the slab_cache field which is in union with mapping, but > before freeing the page, the field is referenced with the "mapping" name when > set to NULL. > > It's IMHO more correct (albeit functionally the same) to use the slab_cache > name as that's the field we use in SL*B, and document why we clear it in a > comment (we don't clear fields such as s_mem or freelist, as page allocator > doesn't care about those). While using the 'mapping' name would automagically > keep the code correct if the unions in struct page changed, such changes should > be done consciously and needed changes evaluated - the comment should help with > that. > > Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
