Messages in this thread | | | Subject | Re: [RFC] mm, THP: Map read-only text segments using large THP pages | From | William Kucharski <> | Date | Thu, 17 May 2018 08:34:56 -0600 |
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> On May 17, 2018, at 1:57 AM, Michal Hocko <mhocko@kernel.org> wrote: > > [CCing Kirill and fs-devel] > > On Mon 14-05-18 07:12:13, William Kucharski wrote: >> One of the downsides of THP as currently implemented is that it only supports >> large page mappings for anonymous pages. > > There is a support for shmem merged already. ext4 was next on the plan > AFAIR but I haven't seen any patches and Kirill was busy with other > stuff IIRC.
I couldn't find anything that would specifically map text pages with large pages, so perhaps this could be integrated with that or I may have simply missed changes that would ultimately provide that functionality.
> >> I embarked upon this prototype on the theory that it would be advantageous to >> be able to map large ranges of read-only text pages using THP as well. > > Can the fs really support THP only for read mappings? What if those > pages are to be shared in a writable mapping as well? In other words > can this all work without a full THP support for a particular fs?
The integration with the page cache would indeed require filesystem support.
The end result I'd like to see is full R/W support for large THP pages; I thought the RO text mapping proof of concept worthwhile to see what kind of results we might see and what the thoughts of the community were.
Thanks for the feedback.
-- Bill
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