On Tue, 17 Jan 2023, Pasha Tatashin wrote: > There is 8 byte page_ext->flags field allocated per page whenever > CONFIG_PAGE_EXTENSION is enabled. However, not every user of page_ext > uses flags. Therefore, check whether flags is needed at least by one > user and if so allocate space for it. > > For example when page_table_check is enabled, on a machine with 128G > of memory before the fix: > > [ 2.244288] allocated 536870912 bytes of page_ext > after the fix: > [ 2.160154] allocated 268435456 bytes of page_ext > > Also, add a kernel-doc comment before page_ext_operations that describes > the fields, and remove check if need() is set, as that is now a required > field. > > Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx> > Acked-by: Vlastimil Babka <vbabka@xxxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
