linux-kernel - Re: [PATCH 3/3] x86, fpu: don't abuse FPU in kernel threads if use_eager

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Date:	Mon, 23 Feb 2015 16:31:05 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Rik van Riel <riel@...hat.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Suresh Siddha <sbsiddha@...il.com>,
	linux-kernel@...r.kernel.org, mingo@...hat.com, hpa@...or.com,
	matt.fleming@...el.com, bp@...e.de, pbonzini@...hat.com,
	tglx@...utronix.de, luto@...capital.net
Subject: Re: [PATCH 3/3] x86, fpu: don't abuse FPU in kernel threads if
 use_eager_fpu()

On Mon, Jan 19, 2015 at 07:52:12PM +0100, Oleg Nesterov wrote:
> Afaics there is no reason why kernel threads should have FPU context
> even if use_eager_fpu() == T. Now that interrupted_kernel_fpu_idle()
> does not check __thread_has_fpu() we can remove the init_fpu() code
				   ^
				... in the use_eager_fpu() case...

I added it to the commit message.

> from eager_fpu_init() and change flush_thread() called by do_execve()
> to initialize FPU.
> 
> Note: of course, the change in flush_thread() is horrible and must be
> cleanuped. We need the new helper, and flush_thread() should return the
> error if init_fpu() fails.
> 
> Signed-off-by: Oleg Nesterov <oleg@...hat.com>

Applied, thanks.

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
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