From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
linux-kernel@vger.kernel.org, Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [PATCH V6 0/4] mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region
Date: Wed, 09 Jan 2019 14:11:25 +0530 [thread overview]
Message-ID: <875zuyjk96.fsf@linux.ibm.com> (raw)
In-Reply-To: <20190108115620.6ec22e7d60b86d5f609d5a87@linux-foundation.org>
Andrew Morton <akpm@linux-foundation.org> writes:
> On Tue, 8 Jan 2019 10:21:06 +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. 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.
>
> Does this code do anything for architectures other than powerpc? If
> not, should we be adding the ifdefs to avoid burdening other
> architectures with unused code?
Any architecture enabling CMA may need this. I will move most of this below
CONFIG_CMA.
-aneesh
next prev parent reply other threads:[~2019-01-09 8:44 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-08 4:51 [PATCH V6 0/4] mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region Aneesh Kumar K.V
2019-01-08 4:51 ` [PATCH V6 1/4] mm/cma: Add PF flag to force non cma alloc Aneesh Kumar K.V
2019-01-09 2:38 ` Andrea Arcangeli
2019-01-08 4:51 ` [PATCH V6 2/4] mm: Add get_user_pages_cma_migrate Aneesh Kumar K.V
2019-01-08 4:51 ` [PATCH V6 3/4] powerpc/mm/iommu: Allow migration of cma allocated pages during mm_iommu_get Aneesh Kumar K.V
2019-01-09 1:53 ` Andrea Arcangeli
2019-01-09 8:40 ` Aneesh Kumar K.V
2019-01-08 4:51 ` [PATCH V6 4/4] powerpc/mm/iommu: Allow large IOMMU page size only for hugetlb backing Aneesh Kumar K.V
2019-01-08 19:56 ` [PATCH V6 0/4] mm/kvm/vfio/ppc64: Migrate compound pages out of CMA region Andrew Morton
2019-01-09 8:41 ` Aneesh Kumar K.V [this message]
2019-01-10 4:11 ` David Gibson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=875zuyjk96.fsf@linux.ibm.com \
--to=aneesh.kumar@linux.ibm.com \
--cc=aarcange@redhat.com \
--cc=aik@ozlabs.ru \
--cc=akpm@linux-foundation.org \
--cc=david@gibson.dropbear.id.au \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mhocko@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).