On Tue, Aug 15, 2023 at 05:06:59PM -0400, Peter Xu wrote: > I split this out from another rfc series. Removed RFC tag because it > wasn't for this patch but for the documentation updates. I'll post the rfc > part alone. Comments welcomed, thanks. I still hate it, as I explained here: https://lore.kernel.org/linux-mm/ZNp7yUgUrIpILnXu@xxxxxxxxxxxxxxxxxxxx/ > > + * When the tail page's mapping field reused, it'll be exempted from > > + * ->mapping poisoning and checks. Also see the macro TAIL_MAPPING. > > + */ > > +#define TAIL_MAPPING_REUSED_MAX (2) > > More importantly, I think this is over-parametrisation. If you start to > use extra fields in struct folio, just change the code in page_alloc.c > directly.
