From: Sean Christopherson <seanjc@google.com>
To: Shivam Kumar <shivam.kumar1@nutanix.com>
Cc: pbonzini@redhat.com, kvm@vger.kernel.org,
Anurag Madnawat <anurag.madnawat@nutanix.com>,
Shaju Abraham <shaju.abraham@nutanix.com>,
Manish Mishra <manish.mishra@nutanix.com>
Subject: Re: [PATCH 4/6] Increment dirty counter for vmexit due to page write fault.
Date: Thu, 18 Nov 2021 17:48:17 +0000 [thread overview]
Message-ID: <YZaR4U5r3j7zWBIF@google.com> (raw)
In-Reply-To: <20211114145721.209219-5-shivam.kumar1@nutanix.com>
On Sun, Nov 14, 2021, Shivam Kumar wrote:
> For a page write fault or "page dirty", the dirty counter of the
> corresponding vCPU is incremented.
>
> Co-developed-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
> Signed-off-by: Anurag Madnawat <anurag.madnawat@nutanix.com>
> Signed-off-by: Shivam Kumar <shivam.kumar1@nutanix.com>
> Signed-off-by: Shaju Abraham <shaju.abraham@nutanix.com>
> Signed-off-by: Manish Mishra <manish.mishra@nutanix.com>
> ---
> virt/kvm/kvm_main.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 1564d3a3f608..55bf92cf9f4f 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -3091,8 +3091,15 @@ void mark_page_dirty_in_slot(struct kvm *kvm,
> if (kvm->dirty_ring_size)
> kvm_dirty_ring_push(kvm_dirty_ring_get(kvm),
> slot, rel_gfn);
> - else
> + else {
> + struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
> +
> + if (vcpu && vcpu->kvm->dirty_quota_migration_enabled &&
> + vcpu->vCPUdqctx)
> + vcpu->vCPUdqctx->dirty_counter++;
Checking dirty_quota_migration_enabled can race, and it'd be far faster to
unconditionally update a counter, e.g. a per-vCPU stat.
> +
> set_bit_le(rel_gfn, memslot->dirty_bitmap);
> + }
> }
> }
> EXPORT_SYMBOL_GPL(mark_page_dirty_in_slot);
> --
> 2.22.3
>
next prev parent reply other threads:[~2021-11-18 17:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-14 14:57 [PATCH 0/6] KVM: Dirty Quota-Based VM Live Migration Auto-Converge Shivam Kumar
2021-11-14 14:57 ` [PATCH 1/6] Define data structures for dirty quota migration Shivam Kumar
2021-11-14 14:57 ` [PATCH 2/6] Init dirty quota flag and allocate memory for vCPUdqctx Shivam Kumar
2021-11-14 14:57 ` [PATCH 3/6] Add KVM_CAP_DIRTY_QUOTA_MIGRATION and handle vCPU page faults Shivam Kumar
2021-11-18 17:57 ` Sean Christopherson
2021-11-19 20:03 ` Shivam Kumar
[not found] ` <02b8fa86-a86b-969e-2137-1953639cb6d2@nutanix.com>
[not found] ` <YZgD0D4536s2DMem@google.com>
2021-11-19 20:21 ` Shivam Kumar
2021-11-25 8:43 ` Shivam Kumar
2021-12-01 17:22 ` Sean Christopherson
2021-11-14 14:57 ` [PATCH 4/6] Increment dirty counter for vmexit due to page write fault Shivam Kumar
2021-11-18 17:48 ` Sean Christopherson [this message]
2021-11-19 19:54 ` Shivam Kumar
2021-11-14 14:57 ` [PATCH 5/6] Exit to userspace when dirty quota is full Shivam Kumar
2021-11-14 14:57 ` [PATCH 6/6] Free vCPUdqctx memory on vCPU destroy Shivam Kumar
2021-11-18 17:46 ` [PATCH 0/6] KVM: Dirty Quota-Based VM Live Migration Auto-Converge Sean Christopherson
-- strict thread matches above, loose matches on Subject: below --
2021-10-26 16:35 Shivam Kumar
2021-10-26 16:35 ` [PATCH 4/6] Increment dirty counter for vmexit due to page write fault Shivam Kumar
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