From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org
Subject: Re: [patch 03/10] KVM: switch dirty_log to mmu_lock protection
Date: Tue, 22 Sep 2009 09:37:51 +0300 [thread overview]
Message-ID: <4AB870BF.4090905@redhat.com> (raw)
In-Reply-To: <20090921234124.205345161@amt.cnet>
On 09/22/2009 02:37 AM, Marcelo Tosatti wrote:
> get_dirty_log vs mark_page_dirty need to be mutually exclusive. Switch
> to mmu_lock protection.
>
>
I'm not sure all archs use mmu_lock. Also, I'm unhappy about
introducing more use (especially as it's often unnecessary, if dirty
logging is turned off for the slot for example).
I think you can use rcu for this as well. When you read the log,
allocate a new empty bitmap, switch the memslots pointer to include it,
and synchronize_srcu(). Now we are certain everyone is using the new
bitmap we can copy the old one to usespace and delete it.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2009-09-22 6:37 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-21 23:37 [patch 00/10] RFC: switch vcpu context to use SRCU Marcelo Tosatti
2009-09-21 23:37 ` [patch 01/10] KVM: modify memslots layout in struct kvm Marcelo Tosatti
2009-09-21 23:37 ` [patch 02/10] KVM: modify alias layout in x86s struct kvm_arch Marcelo Tosatti
2009-09-21 23:37 ` [patch 03/10] KVM: switch dirty_log to mmu_lock protection Marcelo Tosatti
2009-09-22 6:37 ` Avi Kivity [this message]
2009-09-22 12:44 ` Marcelo Tosatti
2009-09-22 12:52 ` Avi Kivity
2009-09-21 23:37 ` [patch 04/10] KVM: split kvm_arch_set_memory_region into prepare and commit Marcelo Tosatti
2009-09-22 6:40 ` Avi Kivity
2009-09-21 23:37 ` [patch 05/10] KVM: introduce gfn_to_pfn_memslot Marcelo Tosatti
2009-09-21 23:37 ` [patch 06/10] KVM: use gfn_to_pfn_memslot in kvm_iommu_map_pages Marcelo Tosatti
2009-09-21 23:37 ` [patch 07/10] KVM: introduce kvm->srcu and convert kvm_set_memory_region to SRCU update Marcelo Tosatti
2009-09-22 6:59 ` Avi Kivity
2009-09-22 16:16 ` Marcelo Tosatti
2009-09-22 10:40 ` Fernando Carrijo
2009-09-22 12:55 ` Marcelo Tosatti
2009-09-24 14:06 ` Marcelo Tosatti
2009-09-24 17:28 ` Paul E. McKenney
2009-09-24 18:05 ` Marcelo Tosatti
2009-09-25 15:05 ` Avi Kivity
2009-09-21 23:37 ` [patch 08/10] KVM: x86: switch kvm_set_memory_alias " Marcelo Tosatti
2009-09-22 7:04 ` Avi Kivity
2009-09-21 23:37 ` [patch 09/10] KVM: convert io_bus to SRCU Marcelo Tosatti
2009-09-21 23:37 ` [patch 10/10] KVM: switch vcpu context to use SRCU Marcelo Tosatti
2009-09-22 7:07 ` Avi Kivity
2009-09-22 7:09 ` [patch 00/10] RFC: " Avi Kivity
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