From: Avi Kivity <avi@redhat.com>
To: Takuya Yoshikawa <takuya.yoshikawa@gmail.com>
Cc: mtosatti@redhat.com, kvm@vger.kernel.org
Subject: Re: [RFC] need to improve slot creation/destruction? -- Re: [RFC][PATCH] srcu: Implement call_srcu()
Date: Tue, 14 Feb 2012 11:52:20 +0200 [thread overview]
Message-ID: <4F3A2ED4.3000104@redhat.com> (raw)
In-Reply-To: <20120210222513.7a8919f2f73604ca25c58bbd@gmail.com>
On 02/10/2012 03:25 PM, Takuya Yoshikawa wrote:
> Avi Kivity <avi@redhat.com> wrote:
>
> > > 2. When we create(and shift?) a memory slot, we call kvm_arch_flush_shadow()
> > > to clear all mmio sptes, again not restricted to that slot.
> > >
> > > /*
> > > * If the new memory slot is created, we need to clear all
> > > * mmio sptes.
> > > */
> > > if (npages && old.base_gfn != mem->guest_phys_addr >> PAGE_SHIFT)
> > > kvm_arch_flush_shadow(kvm);
> >
> > This is pretty rare outside the previous scenario (memory/pci hotplug).
>
> Is this condition correct?
>
> When npages != 0 and old.npages == 0, the slot is being newly created, do we
> really need to flush shadow pages?
>
> This should be
> if (npages && old.npages && (old.base_gfn != base_gfn))
>
Your condition is more correct, but in practice there's no difference.
If old.npages == 0, then old.base_gfn will be 0, and the condition will
fail, except for the first slot created (when the shadow cache is empty
anyway).
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-02-14 9:52 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1328016724.2446.229.camel@twins>
2012-01-31 13:47 ` [RFC][PATCH] srcu: Implement call_srcu() Avi Kivity
2012-01-31 13:50 ` Peter Zijlstra
2012-01-31 22:24 ` Paul E. McKenney
2012-02-01 10:22 ` Peter Zijlstra
2012-02-01 10:44 ` Avi Kivity
2012-02-01 10:49 ` Avi Kivity
2012-02-01 11:00 ` Takuya Yoshikawa
2012-02-01 11:01 ` Avi Kivity
2012-02-01 11:12 ` Takuya Yoshikawa
2012-02-01 13:24 ` Avi Kivity
2012-02-02 5:46 ` [test result] dirty logging without srcu update -- " Takuya Yoshikawa
2012-02-02 10:10 ` Avi Kivity
2012-02-02 10:21 ` Takuya Yoshikawa
2012-02-02 10:21 ` Avi Kivity
2012-02-02 10:40 ` Takuya Yoshikawa
2012-02-02 11:02 ` Avi Kivity
2012-02-02 14:44 ` Takuya Yoshikawa
2012-02-02 14:57 ` Avi Kivity
2012-02-01 13:43 ` Marcelo Tosatti
2012-02-01 15:42 ` Takuya Yoshikawa
2012-02-01 13:50 ` Marcelo Tosatti
2012-02-08 15:43 ` [RFC] need to improve slot creation/destruction? -- " Takuya Yoshikawa
2012-02-08 18:45 ` Marcelo Tosatti
2012-02-09 13:48 ` Takuya Yoshikawa
2012-02-09 14:25 ` Avi Kivity
2012-02-10 17:16 ` Marcelo Tosatti
2012-02-14 9:52 ` Avi Kivity
2012-02-09 14:23 ` Avi Kivity
2012-02-09 14:24 ` Avi Kivity
2012-02-10 13:08 ` Takuya Yoshikawa
2012-02-10 17:17 ` Marcelo Tosatti
2012-02-10 13:25 ` Takuya Yoshikawa
2012-02-14 9:52 ` Avi Kivity [this message]
2012-02-01 14:07 ` Paul E. McKenney
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