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Date: Mon, 16 Mar 2015 15:05:06 -0400
From: Rik van Riel <riel@redhat.com>
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To: Borislav Petkov <bp@suse.de>, Oleg Nesterov <oleg@redhat.com>
CC: Dave Hansen <dave.hansen@intel.com>, Ingo Molnar <mingo@kernel.org>,
        Andy Lutomirski <luto@amacapital.net>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Pekka Riikonen <priikone@iki.fi>, Suresh Siddha <sbsiddha@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        "Yu, Fenghua" <fenghua.yu@intel.com>,
        Quentin Casasnovas <quentin.casasnovas@oracle.com>
Subject: Re: [PATCH 2/4] x86/fpu: introduce restore_init_xstate()
References: <54F74F59.5070107@intel.com> <20150311173346.GB5032@redhat.com> <20150311173429.GD5032@redhat.com> <20150313103406.GB31998@pd.tnic> <20150313143928.GB21603@redhat.com> <20150313152046.GG31998@pd.tnic>
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On 03/13/2015 11:20 AM, Borislav Petkov wrote:
> On Fri, Mar 13, 2015 at 03:39:28PM +0100, Oleg Nesterov wrote:
>> This too needs cleanups. But later ;)
>>
>> Note that xstate_enable_boot_cpu is not called if !cpu_has_xsave, see the
>> check in xsave_init(). Howver, eagerfpu=on will force eager_fpu_init() which
>> calls eager_fpu_init_bp().
>
> Yahaa.
>
> This FPU cleanup fun will keep us busy until Christmas.
>
>> Btw, I was also going to kill eager_fpu_init_bp(). Probably I will
>> send the patch today.
>
> Yap, and I'm wondering if we should kill those func ptrs games there. We
> have BSP and AP CPU init paths so we can be much cleaner there.

I'll wait with the optimization that defers FPU state
loading to the kernel -> user space boundary, until this
current stuff has stabilized...