linux-kernel - Re: [PATCH 3/3] x86,fpu: use disable_task_lazy_fpu

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Message-ID: <54CBFC35.6090005@redhat.com>
Date:	Fri, 30 Jan 2015 16:48:37 -0500
From:	Rik van Riel <riel@...hat.com>
To:	Dave Hansen <dave.hansen@...ux.intel.com>, oleg@...hat.com
CC:	sbsiddha@...il.com, luto@...capital.net, tglx@...utronix.de,
	mingo@...hat.com, hpa@...or.com, fenghua.yu@...el.com,
	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] x86,fpu: use disable_task_lazy_fpu_restore helper

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On 01/30/2015 04:46 PM, Dave Hansen wrote:
> On 01/30/2015 09:49 AM, riel@...hat.com wrote:
>> @@ -440,8 +440,9 @@ static inline fpu_switch_t
>> switch_fpu_prepare(struct task_struct *old, struct ta 
>> new->thread.fpu_counter > 5); if (__thread_has_fpu(old)) { if
>> (!__save_init_fpu(old)) -			cpu = ~0; -		old->thread.fpu.last_cpu
>> = cpu; +			task_disable_lazy_fpu_restore(old); +		else +
>> old->thread.fpu.last_cpu = cpu;
> 
> What is the 'else' doing here?  It seems a bit disconnected from
> the other parts of the patch.

The assignment was already there before, but we would set
cpu to ~0 if __save_init_fpu failed.

Now there are different branches for failure and success,
with the success branch having the same assignment that
was there before.

- -- 
All rights reversed
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