Messages in this thread | | | Date | Mon, 21 Mar 2016 20:06:55 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 0/3] fs, mm: get rid of PAGE_CACHE_* and page_cache_{get,release} macros |
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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
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