From: "Michael S. Tsirkin" <mst@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Christophe de Dinechin <dinechin@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Yan Zhao <yan.y.zhao@intel.com>, Jason Wang <jasowang@redhat.com>,
Kevin Kevin <kevin.tian@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Lei Cao <lei.cao@stratus.com>
Subject: Re: [PATCH v3 12/21] KVM: X86: Implement ring-based dirty memory tracking
Date: Thu, 9 Jan 2020 14:36:56 -0500 [thread overview]
Message-ID: <20200109143620-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200109192116.GE36997@xz-x1>
On Thu, Jan 09, 2020 at 02:21:16PM -0500, Peter Xu wrote:
> On Thu, Jan 09, 2020 at 09:56:10AM -0700, Alex Williamson wrote:
>
> [...]
>
> > > > +Dirty GFNs (Guest Frame Numbers) are stored in the dirty_gfns array.
> > > > +For each of the dirty entry it's defined as:
> > > > +
> > > > +struct kvm_dirty_gfn {
> > > > + __u32 pad;
> > >
> > > How about sticking a length here?
> > > This way huge pages can be dirtied in one go.
> >
> > Not just huge pages, but any contiguous range of dirty pages could be
> > reported far more concisely. Thanks,
>
> I replied in the other thread on why I thought KVM might not suite
> that (while vfio may).
>
> Actually we can even do that for KVM as long as we keep a per-vcpu
> last-dirtied GFN range cache (so we don't publish a dirty GFN right
> after it's dirtied), then we grow that cached dirtied range as long as
> the continuous next/previous page is dirtied. If we found that the
> current dirty GFN is not continuous to the cached range, we publish
> the cached range and let the new GFN be the starting of last-dirtied
> GFN range cache.
>
> However I am not sure how much we'll gain from it. Maybe we can do
> that when we have a real use case for it. For now I'm not sure
> whether it would worth the effort.
>
> Thanks,
I agree for the implementation but I think UAPI should support that
from ground up so we don't need to support two kinds of formats.
> --
> Peter Xu
next prev parent reply other threads:[~2020-01-09 19:37 UTC|newest]
Thread overview: 84+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 14:57 [PATCH v3 00/21] KVM: Dirty ring interface Peter Xu
2020-01-09 14:57 ` [PATCH v3 01/21] vfio: introduce vfio_iova_rw to read/write a range of IOVAs Peter Xu
2020-01-09 14:57 ` [PATCH v3 02/21] drm/i915/gvt: subsitute kvm_read/write_guest with vfio_iova_rw Peter Xu
2020-01-09 14:57 ` [PATCH v3 03/21] KVM: Remove kvm_read_guest_atomic() Peter Xu
2020-01-09 14:57 ` [PATCH v3 04/21] KVM: Add build-time error check on kvm_run size Peter Xu
2020-01-09 14:57 ` [PATCH v3 05/21] KVM: X86: Change parameter for fast_page_fault tracepoint Peter Xu
2020-01-09 14:57 ` [PATCH v3 06/21] KVM: X86: Don't take srcu lock in init_rmode_identity_map() Peter Xu
2020-01-09 14:57 ` [PATCH v3 07/21] KVM: Cache as_id in kvm_memory_slot Peter Xu
2020-01-09 14:57 ` [PATCH v3 08/21] KVM: X86: Drop x86_set_memory_region() Peter Xu
2020-01-09 14:57 ` [PATCH v3 09/21] KVM: X86: Don't track dirty for KVM_SET_[TSS_ADDR|IDENTITY_MAP_ADDR] Peter Xu
2020-01-19 9:01 ` Paolo Bonzini
2020-01-20 6:45 ` Peter Xu
2020-01-21 15:56 ` Sean Christopherson
2020-01-21 16:14 ` Paolo Bonzini
2020-01-28 5:50 ` Peter Xu
2020-01-28 18:24 ` Sean Christopherson
2020-01-31 15:08 ` Peter Xu
2020-01-31 19:33 ` Sean Christopherson
2020-01-31 20:28 ` Peter Xu
2020-01-31 20:36 ` Sean Christopherson
2020-01-31 20:55 ` Peter Xu
2020-01-31 21:29 ` Sean Christopherson
2020-01-31 22:16 ` Peter Xu
2020-01-31 22:20 ` Sean Christopherson
2020-01-09 14:57 ` [PATCH v3 10/21] KVM: Pass in kvm pointer into mark_page_dirty_in_slot() Peter Xu
2020-01-09 14:57 ` [PATCH v3 11/21] KVM: Move running VCPU from ARM to common code Peter Xu
2020-01-09 14:57 ` [PATCH v3 12/21] KVM: X86: Implement ring-based dirty memory tracking Peter Xu
2020-01-09 16:29 ` Michael S. Tsirkin
2020-01-09 16:56 ` Alex Williamson
2020-01-09 19:21 ` Peter Xu
2020-01-09 19:36 ` Michael S. Tsirkin [this message]
2020-01-09 19:15 ` Peter Xu
2020-01-09 19:35 ` Michael S. Tsirkin
2020-01-09 20:19 ` Peter Xu
2020-01-09 22:18 ` Michael S. Tsirkin
2020-01-10 15:29 ` Peter Xu
2020-01-12 6:24 ` Michael S. Tsirkin
2020-01-14 20:01 ` Peter Xu
2020-01-15 6:50 ` Michael S. Tsirkin
2020-01-15 15:20 ` Peter Xu
2020-01-19 9:09 ` Paolo Bonzini
2020-01-19 10:12 ` Michael S. Tsirkin
2020-01-20 7:29 ` Peter Xu
2020-01-20 7:47 ` Michael S. Tsirkin
2020-01-21 8:29 ` Peter Xu
2020-01-21 10:25 ` Paolo Bonzini
2020-01-21 10:24 ` Paolo Bonzini
2020-01-11 4:49 ` kbuild test robot
2020-01-11 4:49 ` kbuild test robot
2020-01-11 23:19 ` kbuild test robot
2020-01-11 23:19 ` kbuild test robot
2020-01-15 6:47 ` Michael S. Tsirkin
2020-01-15 15:27 ` Peter Xu
2020-01-16 8:38 ` Michael S. Tsirkin
2020-01-16 16:27 ` Peter Xu
2020-01-17 9:50 ` Michael S. Tsirkin
2020-01-20 6:48 ` Peter Xu
2020-01-09 14:57 ` [PATCH v3 13/21] KVM: Make dirty ring exclusive to dirty bitmap log Peter Xu
2020-01-09 14:57 ` [PATCH v3 14/21] KVM: Don't allocate dirty bitmap if dirty ring is enabled Peter Xu
2020-01-09 16:41 ` Peter Xu
2020-01-09 14:57 ` [PATCH v3 15/21] KVM: selftests: Always clear dirty bitmap after iteration Peter Xu
2020-01-09 14:57 ` [PATCH v3 16/21] KVM: selftests: Sync uapi/linux/kvm.h to tools/ Peter Xu
2020-01-09 14:57 ` [PATCH v3 17/21] KVM: selftests: Use a single binary for dirty/clear log test Peter Xu
2020-01-09 14:57 ` [PATCH v3 18/21] KVM: selftests: Introduce after_vcpu_run hook for dirty " Peter Xu
2020-01-09 14:57 ` [PATCH v3 19/21] KVM: selftests: Add dirty ring buffer test Peter Xu
2020-01-09 14:57 ` [PATCH v3 20/21] KVM: selftests: Let dirty_log_test async for dirty ring test Peter Xu
2020-01-09 14:57 ` [PATCH v3 21/21] KVM: selftests: Add "-c" parameter to dirty log test Peter Xu
2020-01-09 15:59 ` [PATCH v3 00/21] KVM: Dirty ring interface Michael S. Tsirkin
2020-01-09 16:17 ` Peter Xu
2020-01-09 16:40 ` Michael S. Tsirkin
2020-01-09 17:08 ` Peter Xu
2020-01-09 19:08 ` Michael S. Tsirkin
2020-01-09 19:39 ` Peter Xu
2020-01-09 20:42 ` Paolo Bonzini
2020-01-09 22:28 ` Michael S. Tsirkin
2020-01-10 15:10 ` Peter Xu
2020-01-09 16:47 ` Alex Williamson
2020-01-09 17:58 ` Peter Xu
2020-01-09 19:13 ` Michael S. Tsirkin
2020-01-09 19:23 ` Peter Xu
2020-01-09 19:37 ` Michael S. Tsirkin
2020-01-09 20:51 ` Paolo Bonzini
2020-01-09 22:21 ` Michael S. Tsirkin
2020-01-19 9:11 ` Paolo Bonzini
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