From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: akpm@linux-foundation.org, Michal Hocko <mhocko@kernel.org>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
mpe@ellerman.id.au
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH V3 0/2] mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region
Date: Thu, 04 Oct 2018 14:04:29 +0530 [thread overview]
Message-ID: <87y3beaz56.fsf@linux.ibm.com> (raw)
In-Reply-To: <20180918115839.22154-1-aneesh.kumar@linux.ibm.com>
Hi Andrew,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
> 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.
>
> Aneesh Kumar K.V (2):
> mm: Add get_user_pages_cma_migrate
> powerpc/mm/iommu: Allow migration of cma allocated pages during
> mm_iommu_get
>
> arch/powerpc/mm/mmu_context_iommu.c | 120 ++++++++-----------------
> include/linux/hugetlb.h | 2 +
> include/linux/migrate.h | 3 +
> mm/hugetlb.c | 4 +-
> mm/migrate.c | 132 ++++++++++++++++++++++++++++
> 5 files changed, 174 insertions(+), 87 deletions(-)
Any feedback on this.
-aneesh
prev parent reply other threads:[~2018-10-04 8:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-18 11:58 [PATCH V3 0/2] mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region Aneesh Kumar K.V
2018-09-18 11:58 ` [PATCH V3 1/2] mm: Add get_user_pages_cma_migrate Aneesh Kumar K.V
2018-10-16 4:57 ` Alexey Kardashevskiy
2018-10-16 7:16 ` Aneesh Kumar K.V
2018-10-16 7:52 ` Alexey Kardashevskiy
2018-10-16 8:35 ` Aneesh Kumar K.V
2018-09-18 11:58 ` [PATCH V3 2/2] powerpc/mm/iommu: Allow migration of cma allocated pages during mm_iommu_get Aneesh Kumar K.V
2018-10-16 4:57 ` Alexey Kardashevskiy
2018-10-04 8:34 ` Aneesh Kumar K.V [this message]
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