On Wed, 21 Nov 2018 14:52:56 +0530 "Aneesh Kumar K.V" <aneesh.ku...@linux.ibm.com> wrote:
> Subject: [PATCH V4 0/3] * mm/kvm/vfio/ppc64: Migrate compound pages out of > CMA region Asterisk in title is strange? > ppc64 use CMA area for the allocation of guest page table (hash page table). > We won't > be able to start guest if we fail to allocate hash page table. We have > observed > hash table allocation failure because we failed to migrate pages out of CMA > region > because they were pinned. This happen when we are using VFIO. VFIO on ppc64 > pins > the entire guest RAM. If the guest RAM pages get allocated out of CMA region, > we > won't be able to migrate those pages. The pages are also pinned for the > lifetime of the > guest. > > Currently we support migration of non-compound pages. With THP and with the > addition of > hugetlb migration we can end up allocating compound pages from CMA region. > This > patch series add support for migrating compound pages. The first path adds > the helper > get_user_pages_cma_migrate() which pin the page making sure we migrate them > out of > CMA region before incrementing the reference count. Very little review activity. Perhaps Andrey and/or Michal can find the time.. > mm/migrate.c | 108 ++++++++++++++++++++++++++++++++++++++++ can we make this code disappear when CONFIG_CMA=n?
