From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: Balbir Singh <bsingharora@gmail.com>,
Alexey Kardashevskiy <aik@ozlabs.ru>,
linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org,
kvm@vger.kernel.org
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
Paul Mackerras <paulus@samba.org>
Subject: Re: [v3] KVM: PPC: Book3S HV: Migrate pinned pages out of CMA
Date: Thu, 29 Sep 2016 23:13:15 +1000 (AEST) [thread overview]
Message-ID: <3slFPR2kWQz9sC3@ozlabs.org> (raw)
In-Reply-To: <2e840fe0-40cf-abf0-4fe6-a621ce46ae13@gmail.com>
On Tue, 2016-06-09 at 06:27:31 UTC, Balbir Singh wrote:
> When PCI Device pass-through is enabled via VFIO, KVM-PPC will
> pin pages using get_user_pages_fast(). One of the downsides of
> the pinning is that the page could be in CMA region. The CMA
> region is used for other allocations like the hash page table.
> Ideally we want the pinned pages to be from non CMA region.
>
> This patch (currently only for KVM PPC with VFIO) forcefully
> migrates the pages out (huge pages are omitted for the moment).
> There are more efficient ways of doing this, but that might
> be elaborate and might impact a larger audience beyond just
> the kvm ppc implementation.
>
> The magic is in new_iommu_non_cma_page() which allocates the
> new page from a non CMA region.
>
> I've tested the patches lightly at my end. The full solution
> requires migration of THP pages in the CMA region. That work
> will be done incrementally on top of this.
>
> Signed-off-by: Balbir Singh <bsingharora@gmail.com>
> Acked-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/2e5bbb5461f138cac631fe21b4ad95
cheers
next prev parent reply other threads:[~2016-09-29 13:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 4:25 [RESEND][v2][PATCH] KVM: PPC: Book3S HV: Migrate pinned pages out of CMA Balbir Singh
2016-08-31 4:14 ` Alexey Kardashevskiy
2016-09-06 1:55 ` Balbir Singh
2016-09-06 6:27 ` [PATCH v3] " Balbir Singh
2016-09-06 11:54 ` Anshuman Khandual
2016-09-06 23:53 ` Balbir Singh
2016-09-29 13:13 ` Michael Ellerman [this message]
2016-09-06 5:49 ` [RESEND][v2][PATCH] " Aneesh Kumar K.V
2016-09-06 7:46 ` Balbir Singh
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