linux-kernel - Re: [PATCH v2 5/9] microblaze: entry: Remove unneeded need

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Date:   Tue, 24 Sep 2019 12:30:01 +0200
From:   Michal Simek <monstr@...str.eu>
To:     Valentin Schneider <valentin.schneider@....com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 5/9] microblaze: entry: Remove unneeded need_resched()
 loop

On 23. 09. 19 16:36, Valentin Schneider wrote:
> Since the enabling and disabling of IRQs within preempt_schedule_irq()
> is contained in a need_resched() loop, we don't need the outer arch
> code loop.
> 
> Signed-off-by: Valentin Schneider <valentin.schneider@....com>
> Cc: Michal Simek <monstr@...str.eu>
> ---
>  arch/microblaze/kernel/entry.S | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/arch/microblaze/kernel/entry.S b/arch/microblaze/kernel/entry.S
> index 4e1b567becd6..de7083bd1d24 100644
> --- a/arch/microblaze/kernel/entry.S
> +++ b/arch/microblaze/kernel/entry.S
> @@ -738,14 +738,9 @@ no_intr_resched:
>  	andi	r5, r5, _TIF_NEED_RESCHED;
>  	beqi	r5, restore /* if zero jump over */
>  
> -preempt:
>  	/* interrupts are off that's why I am calling preempt_chedule_irq */
>  	bralid	r15, preempt_schedule_irq
>  	nop
> -	lwi	r11, CURRENT_TASK, TS_THREAD_INFO;	/* get thread info */
> -	lwi	r5, r11, TI_FLAGS;		/* get flags in thread info */
> -	andi	r5, r5, _TIF_NEED_RESCHED;
> -	bnei	r5, preempt /* if non zero jump to resched */
>  restore:
>  #endif
>  	VM_OFF /* MS: turn off MMU */
> 

Looks reasonable and also tested on HW. I expect you want me to take it
via microblaze tree that's why applied.

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Xilinx Microblaze
Maintainer of Linux kernel - Xilinx Zynq ARM and ZynqMP ARM64 SoCs
U-Boot custodian - Xilinx Microblaze/Zynq/ZynqMP/Versal SoCs