On Mon, Mar 21, 2016 at 11:59:25AM -0500, Christoph Lameter wrote: > On Mon, 21 Mar 2016, Kirill A. Shutemov wrote: > > > We do have anon-THP pages on LRU. My huge tmpfs patchset also put > > file-THPs on LRU list. > > So they are on the LRU as 4k units? Tried to look it up. One entry on LRU per huge page. > > > Will this actually work if we have really huge memory (100s of TB) where > > > almost everything is a huge page? Guess we have to use hugetlbfs and we > > > need to think about this as being exempt from paging. > > > > Sorry, I failed to understand your message. > > > > Look on huge tmpfs patchset. It allows both small and huge pages in page > > cache. > > Thus my wonder about this patchset. It seems then that the huge pages are > treated as 4k pages? Otherwise we would have two sizes for pages in the > page cache. Sorry I did not follow that too closely. Will try finding that > patchset. We do have two page sizes in the page cache. It's the only option to get transparent huge pages transparent. We have 512 (on x86-64) entries on radix-tree per huge page, but we can opt to Matthew's multi-order entries later. See e61452365372 "radix_tree: add support for multi-order entries". -- Kirill A. Shutemov -- 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>