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From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>,
	xen-devel <xen-devel@lists.xenproject.org>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>,
	Wei Liu <wei.liu2@citrix.com>,
	Roger Pau Monne <roger.pau@citrix.com>
Subject: Re: [PATCH 4/4] x86/PV: remove unnecessary toggle_guest_pt() overhead
Date: Wed, 3 Apr 2019 19:32:54 +0100	[thread overview]
Message-ID: <3282377e-f615-bd7b-bb6b-6e0a43a79e7c@citrix.com> (raw)
In-Reply-To: <5C88F9F3020000780021E180@prv1-mh.provo.novell.com>

On 13/03/2019 12:39, Jan Beulich wrote:
> While the mere updating of ->pv_cr3 and ->root_pgt_changed aren't overly
> expensive (but still needed only for the toggle_guest_mode() path), the
> effect of the latter on the exit-to-guest path is not insignificant.
> Move the logic into toggle_guest_mode().
>
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

What case does this make faster?  I'm really struggling to see how this
is safe.

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  reply	other threads:[~2019-04-03 18:32 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-13 12:18 [PATCH 0/4] x86: some further follow-up to recent XSAs Jan Beulich
2019-03-13 12:38 ` [PATCH 1/4] x86: suppress XPTI-related TLB flushes when possible Jan Beulich
2019-04-03 18:52   ` Andrew Cooper
2019-04-04 10:07     ` Jan Beulich
2019-03-13 12:38 ` [PATCH 2/4] x86: relax a few get_gfn() invocations Jan Beulich
2019-04-03 18:16   ` Andrew Cooper
2019-04-05 10:30   ` George Dunlap
2019-04-05 10:30     ` [Xen-devel] " George Dunlap
2019-04-05 10:52     ` Jan Beulich
2019-04-05 10:52       ` [Xen-devel] " Jan Beulich
2019-03-13 12:38 ` [PATCH 3/4] x86/mm: drop redundant local variable from _get_page_type() Jan Beulich
2019-04-03 18:17   ` Andrew Cooper
2019-04-05 10:37   ` George Dunlap
2019-04-05 10:37     ` [Xen-devel] " George Dunlap
2019-03-13 12:39 ` [PATCH 4/4] x86/PV: remove unnecessary toggle_guest_pt() overhead Jan Beulich
2019-04-03 18:32   ` Andrew Cooper [this message]
2019-04-04  9:42     ` Jan Beulich
     [not found]   ` <5C88F9F30200000000104057@prv1-mh.provo.novell.com>
     [not found]     ` <5C88F9F3020000780023294C@prv1-mh.provo.novell.com>
2019-05-27  9:25       ` Ping: " Jan Beulich
2019-05-27  9:25         ` [Xen-devel] " Jan Beulich

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