From: David Vrabel <david.vrabel@citrix.com>
To: Juergen Gross <jgross@suse.com>, xen-devel@lists.xenproject.org
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Subject: Re: [PATCH 3/3] x86/xen: optimize get_phys_to_machine()
Date: Wed, 7 Jan 2015 15:24:18 +0000 [thread overview]
Message-ID: <54AD4FA2.7020106@citrix.com> (raw)
In-Reply-To: <54AD4E2E.2070103@suse.com>
On 07/01/15 15:18, Juergen Gross wrote:
> On 01/07/2015 03:47 PM, David Vrabel wrote:
>> The page table walk is only needed to distinguish between identity and
>> missing, both of which have INVALID_P2M_ENTRY.
>
> As get_phys_to_machine is called by __pfn_to_mfn() only which already
> checks for mfn == INVALID_P2M_ENTRY this optimization will have an
> effect only in the early boot case with pfn >= xen_p2m_size.
>
> I doubt this is necessary.
Doh. Now I remember suggesting this "optimization" before and getting
the same answer from you.
I'll drop this patch.
David
prev parent reply other threads:[~2015-01-07 15:24 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-07 14:47 [PATCHv1 0/3] x86/xen: fixes and improvements to linear p2m David Vrabel
2015-01-07 14:47 ` [PATCH 1/3] x86/xen: don't count how many PFNs are identity mapped David Vrabel
2015-01-07 15:10 ` Juergen Gross
2015-01-07 14:47 ` [PATCH 2/3] x86/xen: add extra memory for remapped frames during setup David Vrabel
2015-01-07 15:12 ` Juergen Gross
2015-01-07 14:47 ` [PATCH 3/3] x86/xen: optimize get_phys_to_machine() David Vrabel
2015-01-07 15:18 ` Juergen Gross
2015-01-07 15:24 ` David Vrabel [this message]
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