| Date | Thu, 19 Mar 2015 19:10:43 +0200 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv4 00/24] THP refcounting redesign |
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On Tue, Mar 17, 2015 at 03:12:05PM +0530, Aneesh Kumar K.V wrote: > "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> writes: > > > Hello everybody, > > > > It's bug-fix update of my thp refcounting work. > > > > The goal of patchset is to make refcounting on THP pages cheaper with > > simpler semantics and allow the same THP compound page to be mapped with > > PMD and PTEs. This is required to get reasonable THP-pagecache > > implementation. > > > > With the new refcounting design it's much easier to protect against > > split_huge_page(): simple reference on a page will make you the deal. > > It makes gup_fast() implementation simpler and doesn't require > > special-case in futex code to handle tail THP pages. > > > > It should improve THP utilization over the system since splitting THP in > > one process doesn't necessary lead to splitting the page in all other > > processes have the page mapped. > > I tested this patch on ppc64 and verified thp allocation and split. > I also checked the subpage_prot and it worked as expected. I will > run more tests with this series and update if I find any issues.
Thanks a lot.
Could you also prepare patch to drop power-specific code related to pmd_trans_splitting()? It's not needed anymore with the patchset.
-- Kirill A. Shutemov
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