linux-kernel - Re: [PATCH 4/5] x86/fpu: Speed up lazy FPU restores slightly

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Message-ID: <20160123233515.GF16329@pd.tnic>
Date:	Sun, 24 Jan 2016 00:35:15 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Andy Lutomirski <luto@...capital.net>
Cc:	Andy Lutomirski <luto@...nel.org>, X86 ML <x86@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Fenghua Yu <fenghua.yu@...el.com>,
	Oleg Nesterov <oleg@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@...el.com>,
	yu-cheng yu <yu-cheng.yu@...el.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Rik van Riel <riel@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 4/5] x86/fpu: Speed up lazy FPU restores slightly

On Sat, Jan 23, 2016 at 02:09:59PM -0800, Andy Lutomirski wrote:
> Maybe this will be just cpu_has some day if my theory about the new
> improved static_cpu_has being shorter than boot_cpu_has pans out :)

Yeah, I have the static_cpu_has() simplification patchset v2 ready, will
send out tomorrow.

And yeah, as a next step, we probably should think about hiding
boot_cpu_has() and using solely static_cpu_has() everywhere instead.

The cpu_has() thing takes struct cpuinfo_x86 * and I'll bet a bunch of
money that a lot of the callsites could do static_cpu_has(), i.e., look
at boot CPU bits instead. That's for later, though.

-- 
Regards/Gruss,
    Boris.

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