On Fri, 18 Jan 2013 17:57:25 +0200 "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > Hi, > > PAGE_CACHE_* macros were introduced long time ago in hope to implement > page cache with larger chunks than one page in future. > > In fact it was never done. > > Some code paths assume PAGE_CACHE_SIZE <= PAGE_SIZE. E.g. we use > zero_user_segments() to clear stale parts of page on cache filling, but > the function is implemented only for individual small page. > > It's unlikely that global switch to PAGE_CACHE_SIZE > PAGE_SIZE will never > happen since it will affect to much code at once. > > I think support of larger chunks in page cache can be in implemented in > some form of THP with per-fs enabling. > > Is it time to get rid of PAGE_CACHE_* macros? > I can prepare patchset if it's okay. The distinct PAGE_CACHE_SIZE has never been used for anything, but I do kinda like it for documentary reasons: PAGE_SIZE is a raw, low-level thing and PAGE_CACHE_SIZE is the specialized we're-doing-pagecache-stuff thing. But I'm sure I could get used to not having it ;) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>