linux-kernel - Re: Re: [PATCH v2 3/3] i387: support lazy restore of FPU state

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Date:	Tue, 21 Feb 2012 02:23:14 +0000 (GMT)
From:	Jongman Heo <jongman.heo@...sung.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Josh Boyer <jwboyer@...il.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	"x86@...nel.org" <x86@...nel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Re: [PATCH v2 3/3] i387: support lazy restore of FPU state


> Sender : Linus Torvalds<torvalds@...ux-foundation.org>
> Date : 2012-02-21 11:18 (GMT+09:00)
> Title : Re: [PATCH v2 3/3] i387: support lazy restore of FPU state
> 
> On Mon, Feb 20, 2012 at 6:10 PM, Linus Torvalds
> wrote:
> >
> > The attached trivial patch fixes it, I bet.
> 
> Actually, it doesn't fix it on x86-32, because we actually have an
> #ifdef CONFIG_X86_64 around the "current_task" definition due to
> pointless differences in how we do that on x86-64 and x86-32.
> 
> So much for the "common" part of "arch/x86/kernel/cpu/common.c"
> 
> > Although I do wonder if we should just make kernel_fpu_begin() be a
> > real function instead of inlining it. I'm not sure it makes sense to
> > inline that thing, and it might be better to export that one instead.
> 
> I do think that would be better in the long run, but for now here's an
> updated "trivial" patch to fix it.
> 
> I want the fpu_owner_task to be declared next to the cache-hot
> task-switching stuff, and since they are different on 32-bit and
> 64-bit (for no really good reason), that gets duplicated too. Sad.
> 
>                         Linus
> 
>                       Linus

Yeah, this patch fixes my x86-32 build.

Thanks,
Jongman Heo.