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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "James Hogan" <jhogan@kernel.org>,
	"Paul Mackerras" <paulus@ozlabs.org>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Janosch Frank" <frankja@linux.ibm.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Marc Zyngier" <maz@kernel.org>
Cc: Wanpeng Li <wanpengli@tencent.com>,
	kvm@vger.kernel.org, David Hildenbrand <david@redhat.com>,
	Joerg Roedel <joro@8bytes.org>, Cornelia Huck <cohuck@redhat.com>,
	linux-mips@vger.kernel.org, kvm-ppc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	kvmarm@lists.cs.columbia.edu, Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH v3 00/15] KVM: Dynamically size memslot arrays
Date: Tue, 3 Dec 2019 14:14:33 -0800
Message-ID: <20191203221433.GK19877@linux.intel.com> (raw)
In-Reply-To: <20191024230744.14543-1-sean.j.christopherson@intel.com>

On Thu, Oct 24, 2019 at 04:07:29PM -0700, Sean Christopherson wrote:
> The end goal of this series is to dynamically size the memslot array so
> that KVM allocates memory based on the number of memslots in use, as
> opposed to unconditionally allocating memory for the maximum number of
> memslots.  On x86, each memslot consumes 88 bytes, and so with 2 address
> spaces of 512 memslots, each VM consumes ~90k bytes for the memslots.
> E.g. given a VM that uses a total of 30 memslots, dynamic sizing reduces
> the memory footprint from 90k to ~2.6k bytes.
> 
> The changes required to support dynamic sizing are relatively small,
> e.g. are essentially contained in patches 14/15 and 15/15.  Patches 1-13
> clean up the memslot code, which has gotten quite crusty, especially
> __kvm_set_memory_region().  The clean up is likely not strictly necessary
> to switch to dynamic sizing, but I didn't have a remotely reasonable
> level of confidence in the correctness of the dynamic sizing without first
> doing the clean up.
> 
> Christoffer, I added your Tested-by to the patches that I was confident
> would be fully tested based on the desription of what you tested.  Let me
> know if you disagree with any of 'em.
> 
> v3:
>   - Fix build errors on PPC and MIPS due to missed params during
>     refactoring [kbuild test robot].
>   - Rename the helpers for update_memslots() and add comments describing
>     the new algorithm and how it interacts with searching [Paolo].
>   - Remove the unnecessary and obnoxious warning regarding memslots being
>     a flexible array [Paolo].
>   - Fix typos in the changelog of patch 09/15 [Christoffer].
>   - Collect tags [Christoffer].
> 
> v2:
>   - Split "Drop kvm_arch_create_memslot()" into three patches to move
>     minor functional changes to standalone patches [Janosch].
>   - Rebase to latest kvm/queue (f0574a1cea5b, "KVM: x86: fix ...")
>   - Collect an Acked-by and a Reviewed-by

Paolo, do you want me to rebase this to the latest kvm/queue?
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Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24 23:07 Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 01/15] KVM: Reinstall old memslots if arch preparation fails Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 02/15] KVM: Don't free new memslot if allocation of said memslot fails Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 03/15] KVM: PPC: Move memslot memory allocation into prepare_memory_region() Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 04/15] KVM: x86: Allocate memslot resources during prepare_memory_region() Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 05/15] KVM: Drop kvm_arch_create_memslot() Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 06/15] KVM: Explicitly free allocated-but-unused dirty bitmap Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 07/15] KVM: Refactor error handling for setting memory region Sean Christopherson
2019-12-05  9:49   ` Philippe Mathieu-Daudé
2019-10-24 23:07 ` [PATCH v3 08/15] KVM: Move setting of memslot into helper routine Sean Christopherson
2019-12-05  9:54   ` Philippe Mathieu-Daudé
2019-10-24 23:07 ` [PATCH v3 09/15] KVM: Move memslot deletion to helper function Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 10/15] KVM: Simplify kvm_free_memslot() and all its descendents Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 11/15] KVM: Clean up local variable usage in __kvm_set_memory_region() Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 12/15] KVM: Provide common implementation for generic dirty log functions Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 13/15] KVM: Ensure validity of memslot with respect to kvm_get_dirty_log() Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 14/15] KVM: Terminate memslot walks via used_slots Sean Christopherson
2019-10-24 23:07 ` [PATCH v3 15/15] KVM: Dynamically size memslot array based on number of used slots Sean Christopherson
2019-10-25 13:28 ` [PATCH v3 00/15] KVM: Dynamically size memslot arrays Christoffer Dall
2019-10-25 16:30 ` Marc Zyngier
2019-12-03 22:14 ` Sean Christopherson [this message]

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