Re: [RFC 06/16] gic: drop interrupts enabling on interrupts processing

From: Julien Grall <Julien.Grall@arm.com>
To: Andrii Anisov <andrii.anisov@gmail.com>
Cc: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>,
	nd <nd@arm.com>, Andrii Anisov <andrii_anisov@epam.com>,
	Stefano Stabellini <sstabellini@kernel.org>
Subject: Re: [RFC 06/16] gic: drop interrupts enabling on interrupts processing
Date: Wed, 28 Nov 2018 22:06:28 +0000	[thread overview]
Message-ID: <8a5794cb-f5f1-1135-0101-2114fa999894@arm.com> (raw)
In-Reply-To: <1543440731-21947-7-git-send-email-andrii.anisov@gmail.com>

On 28/11/2018 21:32, Andrii Anisov wrote:
> From: Andrii Anisov <andrii_anisov@epam.com>
> 
> This reduces the number of context switches in case we have an
> interrupt storm. We will read out all of those interrupt in the
> loop anyway.

This needs a better explanation. You might want to have a look at the 
details I provided in another discussion.

In general, I would like any changes in the vGIC to be very detailed. As 
they are usually subbtle implication on the rest of the code base.

> 
> Signed-off-by: Andrii Anisov <andrii_anisov@epam.com>
> ---
>   xen/arch/arm/gic.c | 2 --
>   1 file changed, 2 deletions(-)
> 
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 77fc06f..b10783b 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -390,10 +390,8 @@ void gic_interrupt(struct cpu_user_regs *regs, int is_fiq)
>   
>           if ( likely(irq >= 16 && irq < 1020) )
>           {
> -            local_irq_enable();
>               isb();
>               do_IRQ(regs, irq, is_fiq);
> -            local_irq_disable();
>           }
>   #ifdef CONFIG_GICV3
>           else if ( is_lpi(irq) )
> 

-- 
Julien Grall
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