Excerpts from Matthew Wilcox's message of March 19, 2021 11:25 am: > 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 The 7% improvement comes from cache cold kbuild by improving IO patterns? Just wondering what kind of readahead is enabled by this that can't be done with base page size. Thanks, Nick
