From: Marcelo Tosatti <mtosatti@redhat.com>
To: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Cc: avi@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] KVM: Avoid checking huge page mappings in get_dirty_log()
Date: Wed, 14 Mar 2012 07:58:13 -0300 [thread overview]
Message-ID: <20120314105813.GA13956@amt.cnet> (raw)
In-Reply-To: <20120314143432.c982e893.yoshikawa.takuya@oss.ntt.co.jp>
On Wed, Mar 14, 2012 at 02:34:32PM +0900, Takuya Yoshikawa wrote:
> Marcelo Tosatti <mtosatti@redhat.com> wrote:
>
> > guest fault enable dirty logging
> >
> > tdp_page_fault (all _page_fault functions) kvm_set_memory_region
> >
> >
> > level = mapping_level(vcpu, gfn)
> > (finds level == 2 or 3)
> >
> >
> > rcu_assign_pointer(slot
> > with
> > ->dirty_bitmap)
> > synchronize_srcu_expedited()
>
> Isn't here still in the SRCU read-side critical section?
>
> > schedule()
> > kvm_arch_commit_memory_region()
> > spin_lock(mmu_lock)
> > kvm_mmu_slot_remove_write_access()
> > removes large sptes
> > spin_unlock(mmu_lock)
> > spin_lock(mmu_lock)
> > create large spte accordingly
> > to level above
> > spin_unlock(mmu_lock)
> >
>
> If so, we cannot start kvm_arch_commit_memory_region() until the completion
> of the SRCU critical section and this race will not happen.
>
> Takuya
Correct.
next prev parent reply other threads:[~2012-03-14 11:01 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-01 10:30 [PATCH 0/4] KVM: srcu-less dirty logging -v2 Takuya Yoshikawa
2012-03-01 10:31 ` [PATCH 1/4] KVM: MMU: Split the main body of rmap_write_protect() off from others Takuya Yoshikawa
2012-03-12 7:39 ` Takuya Yoshikawa
2012-03-12 7:52 ` Takuya Yoshikawa
2012-03-01 10:32 ` [PATCH 2/4] KVM: Avoid checking huge page mappings in get_dirty_log() Takuya Yoshikawa
2012-03-02 2:56 ` Takuya Yoshikawa
2012-03-02 5:11 ` Takuya Yoshikawa
2012-03-12 18:04 ` Avi Kivity
2012-03-13 9:20 ` Takuya Yoshikawa
2012-03-13 10:12 ` Avi Kivity
2012-03-13 23:04 ` Marcelo Tosatti
2012-03-14 1:04 ` Takuya Yoshikawa
2012-03-14 5:34 ` Takuya Yoshikawa
2012-03-14 10:58 ` Marcelo Tosatti [this message]
2012-03-01 10:33 ` [PATCH 3/4] KVM: Switch to srcu-less get_dirty_log() Takuya Yoshikawa
2012-03-03 5:21 ` [PATCH 3/4 changelog-v2] " Takuya Yoshikawa
2012-03-06 11:15 ` Marcelo Tosatti
2012-03-06 14:43 ` Takuya Yoshikawa
2012-03-06 15:01 ` Marcelo Tosatti
2012-03-06 15:23 ` Takuya Yoshikawa
2012-03-06 15:28 ` Marcelo Tosatti
2012-03-07 8:07 ` Takuya Yoshikawa
2012-03-07 23:25 ` Marcelo Tosatti
2012-03-08 1:35 ` Takuya Yoshikawa
2012-03-09 0:08 ` Marcelo Tosatti
2012-03-12 12:05 ` Avi Kivity
2012-03-07 8:18 ` Takuya Yoshikawa
2012-03-07 23:20 ` Marcelo Tosatti
2012-03-16 5:03 ` [PATCH 3/4] " Xiao Guangrong
2012-03-16 6:55 ` Takuya Yoshikawa
2012-03-16 7:30 ` Xiao Guangrong
2012-03-16 7:55 ` Takuya Yoshikawa
2012-03-16 8:28 ` Xiao Guangrong
2012-03-16 9:44 ` Takuya Yoshikawa
2012-03-19 9:34 ` Xiao Guangrong
2012-03-19 10:15 ` Takuya Yoshikawa
2012-03-01 10:34 ` [PATCH 4/4] KVM: Remove unused dirty_bitmap_head and nr_dirty_pages Takuya Yoshikawa
2012-03-03 5:12 ` [PATCH 0/4] KVM: srcu-less dirty logging -v2 Takuya Yoshikawa
2012-03-20 14:43 ` Avi Kivity
-- strict thread matches above, loose matches on Subject: below --
2012-02-23 11:33 [PATCH 0/4] KVM: srcu-less dirty logging Takuya Yoshikawa
2012-02-23 11:34 ` [PATCH 2/4] KVM: Avoid checking huge page mappings in get_dirty_log() Takuya Yoshikawa
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