| Message ID | 20190114095438.32470-1-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region | expand |
On Mon, 14 Jan 2019 15:24:32 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> wrote: > 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. Very little review activity is in evidence. Please identify some appropriate reviewers and ask them to take a look?
[patch 1/4]: OK. I guess. Was this worth consuming our last PF_ flag? [patch 2/4]: unreviewed [patch 3/4]: unreviewed, mpe still unhappy, I expect? [patch 4/4]: unreviewed
Andrew Morton <akpm@linux-foundation.org> writes: > [patch 1/4]: OK. I guess. Was this worth consuming our last PF_ flag? That was done based on request from Andrea and it also helps in avoiding allocating pages from CMA region where we know we are anyway going to migrate them out. So yes, this helps. > [patch 2/4]: unreviewed > [patch 3/4]: unreviewed, mpe still unhappy, I expect? I did reply to that email. I guess mpe is ok with that? > [patch 4/4]: unreviewed -aneesh
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes: > Andrew Morton <akpm@linux-foundation.org> writes: > >> [patch 1/4]: OK. I guess. Was this worth consuming our last PF_ flag? > > That was done based on request from Andrea and it also helps in avoiding > allocating pages from CMA region where we know we are anyway going to > migrate them out. So yes, this helps. > >> [patch 2/4]: unreviewed >> [patch 3/4]: unreviewed, mpe still unhappy, I expect? > > I did reply to that email. I guess mpe is ok with that? It would be nice to fold your explanation about DAX into the change log, so it's there for people to see. And I think my comment about initialising ret still stands. cheers
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. Changes from V6: * use get_user_pages_longterm instead of get_user_pages_cma_migrate() Changes from V5: * Add PF_MEMALLOC_NOCMA * remote __GFP_THISNODE when allocating target page for migration Changes from V4: * use __GFP_NOWARN when allocating pages to avoid page allocation failure warnings. Changes from V3: * Move the hugetlb check before transhuge check * Use compound head page when isolating hugetlb page Aneesh Kumar K.V (4): mm/cma: Add PF flag to force non cma alloc mm: Update get_user_pages_longterm to migrate pages allocated from CMA region powerpc/mm/iommu: Allow migration of cma allocated pages during mm_iommu_do_alloc powerpc/mm/iommu: Allow large IOMMU page size only for hugetlb backing arch/powerpc/mm/mmu_context_iommu.c | 146 ++++++-------------- include/linux/hugetlb.h | 2 + include/linux/mm.h | 3 +- include/linux/sched.h | 1 + include/linux/sched/mm.h | 48 +++++-- mm/gup.c | 200 ++++++++++++++++++++++++---- mm/hugetlb.c | 4 +- 7 files changed, 267 insertions(+), 137 deletions(-)