From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Jürgen Groß" <jgross@suse.com>,
xen-devel@lists.xenproject.org, x86@kernel.org,
linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
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luto@kernel.org, "Thomas Gleixner" <tglx@linutronix.de>,
"Ingo Molnar" <mingo@redhat.com>,
"Borislav Petkov" <bp@alien8.de>,
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"Boris Ostrovsky" <boris.ostrovsky@oracle.com>,
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"VMware, Inc." <pv-drivers@vmware.com>,
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"Steven Rostedt" <rostedt@goodmis.org>,
"Ben Segall" <bsegall@google.com>, "Mel Gorman" <mgorman@suse.de>,
"Daniel Bristot de Oliveira" <bristot@redhat.com>
Subject: Re: [PATCH v2 00/12] x86: major paravirt cleanup
Date: Wed, 16 Dec 2020 18:58:28 +0100 [thread overview]
Message-ID: <20201216175828.GQ3040@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201216165605.4h5q7os5dutjgdqi@treble>
On Wed, Dec 16, 2020 at 10:56:05AM -0600, Josh Poimboeuf wrote:
> On Wed, Dec 16, 2020 at 09:40:59AM +0100, Peter Zijlstra wrote:
> > > Could we make it easier by caching the shared
> > > per-alt-group CFI state somewhere along the way?
> >
> > Yes, but when I tried it grew the code required. Runtime costs would be
> > less, but I figured that since alternatives are typically few and small,
> > that wasn't a real consideration.
>
> Aren't alternatives going to be everywhere now with paravirt using them?
What I meant was, they're either 2-3 wide and only a few instructions
long. Which greatly bounds the actual complexity of the algorithm,
however daft.
> > No real objection, I just didn't do it because 1) it works, and 2) even
> > moar lines.
>
> I'm kind of surprised it would need moar lines. Let me play around with
> it and maybe I'll come around ;-)
Please do, it could be getting all the niggly bits right exhausted my
brain enough to miss the obvious ;-)
prev parent reply other threads:[~2020-12-16 18:00 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 11:46 [PATCH v2 00/12] x86: major paravirt cleanup Juergen Gross
2020-11-20 11:46 ` [PATCH v2 06/12] x86/paravirt: switch time pvops functions to use static_call() Juergen Gross
2020-11-20 12:01 ` Peter Zijlstra
2020-11-20 12:07 ` Jürgen Groß
2020-11-20 12:53 ` [PATCH v2 00/12] x86: major paravirt cleanup Peter Zijlstra
2020-11-23 13:43 ` Peter Zijlstra
2020-12-15 11:42 ` Jürgen Groß
2020-12-15 14:18 ` Peter Zijlstra
2020-12-15 14:54 ` Peter Zijlstra
2020-12-15 15:07 ` Jürgen Groß
2020-12-16 0:38 ` Josh Poimboeuf
2020-12-16 8:40 ` Peter Zijlstra
2020-12-16 16:56 ` Josh Poimboeuf
2020-12-16 17:58 ` Peter Zijlstra [this message]
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