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Message-ID: <Zhzl6TE57LCjdJXL@alpha.franken.de>
Date: Mon, 15 Apr 2024 10:31:37 +0200
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Yury Norov <yury.norov@...il.com>
Cc: Florian Fainelli <f.fainelli@...il.com>, linux-mips@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] MIPS: SGI-IP27: micro-optimize arch_init_irq()
On Sat, Apr 13, 2024 at 11:49:13AM -0700, Yury Norov wrote:
> The function sets adjasted groups of bits in hub_irq_map by using
> for-loops. There's a bitmap_set() function dedicated to do this.
>
> Because [0, CPU_CALL_B_IRQ] and [NI_BRDCAST_ERR_A, MSC_PANIC_INTR]
> ranges belong to the same machine word, bitmap_set() would boil down
> to an inline wrapper in both cases, avoiding generating a loop, whth
> the associate overhead.
>
> Signed-off-by: Yury Norov <yury.norov@...il.com>
> ---
> arch/mips/sgi-ip27/ip27-irq.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/arch/mips/sgi-ip27/ip27-irq.c b/arch/mips/sgi-ip27/ip27-irq.c
> index e6ca34cc9853..3c3a4b56ab95 100644
> --- a/arch/mips/sgi-ip27/ip27-irq.c
> +++ b/arch/mips/sgi-ip27/ip27-irq.c
> @@ -279,11 +279,8 @@ void __init arch_init_irq(void)
> * Mark these as reserved right away so they won't be used accidentally
> * later.
> */
> - for (i = 0; i <= CPU_CALL_B_IRQ; i++)
> - set_bit(i, hub_irq_map);
> -
> - for (i = NI_BRDCAST_ERR_A; i <= MSC_PANIC_INTR; i++)
> - set_bit(i, hub_irq_map);
> + bitmap_set(hub_irq_map, 0, CPU_CALL_B_IRQ + 1);
> + bitmap_set(hub_irq_map, NI_BRDCAST_ERR_A, MSC_PANIC_INTR - NI_BRDCAST_ERR_A + 1);
>
> fn = irq_domain_alloc_named_fwnode("HUB");
> WARN_ON(fn == NULL);
> --
> 2.40.1
applied to mips-next.
Thomas.
--
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea. [ RFC1925, 2.3 ]
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