linux-kernel - Re: [PATCH 1/3] x86, fpu: unlazy_fpu: don't reset thread.fpu

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Message-ID: <54CAA572.6060206@redhat.com>
Date:	Thu, 29 Jan 2015 16:26:10 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Oleg Nesterov <oleg@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>
CC:	Suresh Siddha <sbsiddha@...il.com>,
	Andy Lutomirski <luto@...capital.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	Fenghua Yu <fenghua.yu@...el.com>,
	the arch/x86 maintainers <x86@...nel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] x86, fpu: unlazy_fpu: don't reset thread.fpu_counter

On 01/29/2015 04:07 PM, Oleg Nesterov wrote:
> It is not clear why the "else" branch clears ->fpu_counter, this makes
> no sense.
> 
> If use_eager_fpu() then this has no effect. Otherwise, if we actually
> wanted to prevent fpu preload after the context switch we would need to
> reset it unconditionally, even if __thread_has_fpu().
> 
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>

Reviewed-by: Rik van Riel <riel@...hat.com>

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