On Fri, Mar 19, 2021 at 01:25:27AM +0000, Matthew Wilcox wrote: > On Fri, Mar 19, 2021 at 10:56:45AM +1100, Balbir Singh wrote: > > On Fri, Mar 05, 2021 at 04:18:37AM +0000, Matthew Wilcox (Oracle) wrote: > > > A struct folio refers to an entire (possibly compound) page. A function > > > which takes a struct folio argument declares that it will operate on the > > > entire compound page, not just PAGE_SIZE bytes. In return, the caller > > > guarantees that the pointer it is passing does not point to a tail page. > > > > > > > Is this a part of a larger use case or general cleanup/refactor where > > the split between page and folio simplify programming? > > The goal here is to manage memory in larger chunks. Pages are now too > small for just about every workload. Even compiling the kernel sees a 7% > performance improvement just by doing readahead using relatively small > THPs (16k-256k). You can see that work here: > https://git.infradead.org/users/willy/pagecache.git/shortlog/refs/heads/master > > I think Kirill, Hugh and others have done a fantastic job stretching > the page struct to work in shmem, but we really need a different type > to avoid people writing code that _looks_ right but is actually buggy. > So I'm starting again, this time with the folio metaphor. Thanks, makes sense, I'll take a look. Balbir Singh.
