linux-kernel - Re: memblock: Refactor functions to set/clear MEMBLOCK

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Message-ID: <546301A4.3090209@jp.fujitsu.com>
Date:	Wed, 12 Nov 2014 15:43:48 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	<tony.luck@...el.com>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Santosh Shilimkar <santosh.shilimkar@...com>,
	Tang Chen <tangchen@...fujitsu.com>,
	Grygorii Strashko <grygorii.strashko@...com>,
	Zhang Yanfei <zhangyanfei@...fujitsu.com>,
	Philipp Hachtmann <phacht@...ux.vnet.ibm.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Emil Medve <Emilian.Medve@...escale.com>, <linux-mm@...ck.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: memblock: Refactor functions to set/clear MEMBLOCK_HOTPLUG

(2014/11/11 4:05), tony.luck@...el.com wrote:
> There is a lot of duplication in the rubric around actually setting or
> clearing a mem region flag. Create a new helper function to do this and
> reduce each of memblock_mark_hotplug() and memblock_clear_hotplug() to
> a single line.
> 
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> 
> ---

The refactoring looks good.

Thanks,
Yasuaki Ishimatsu

> 
> This will be useful if someone were to add a new mem region flag - which
> I hope to be doing some day soon. But it looks like a plausible cleanup
> even without that - so I'd like to get it out of the way now.
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 6ecb0d937fb5..252b77bdf65e 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -715,16 +715,13 @@ int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
>   }
>   
>   /**
> - * memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
> - * @base: the base phys addr of the region
> - * @size: the size of the region
>    *
> - * This function isolates region [@base, @base + @size), and mark it with flag
> - * MEMBLOCK_HOTPLUG.
> + * This function isolates region [@base, @base + @size), and sets/clears flag
>    *
>    * Return 0 on succees, -errno on failure.
>    */
> -int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
> +static int __init_memblock memblock_setclr_flag(phys_addr_t base,
> +				phys_addr_t size, int set, int flag)
>   {
>   	struct memblock_type *type = &memblock.memory;
>   	int i, ret, start_rgn, end_rgn;
> @@ -734,37 +731,37 @@ int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
>   		return ret;
>   
>   	for (i = start_rgn; i < end_rgn; i++)
> -		memblock_set_region_flags(&type->regions[i], MEMBLOCK_HOTPLUG);
> +		if (set)
> +			memblock_set_region_flags(&type->regions[i], flag);
> +		else
> +			memblock_clear_region_flags(&type->regions[i], flag);
>   
>   	memblock_merge_regions(type);
>   	return 0;
>   }
>   
>   /**
> - * memblock_clear_hotplug - Clear flag MEMBLOCK_HOTPLUG for a specified region.
> + * memblock_mark_hotplug - Mark hotpluggable memory with flag MEMBLOCK_HOTPLUG.
>    * @base: the base phys addr of the region
>    * @size: the size of the region
>    *
> - * This function isolates region [@base, @base + @size), and clear flag
> - * MEMBLOCK_HOTPLUG for the isolated regions.
> + * Return 0 on succees, -errno on failure.
> + */
> +int __init_memblock memblock_mark_hotplug(phys_addr_t base, phys_addr_t size)
> +{
> +	return memblock_setclr_flag(base, size, 1, MEMBLOCK_HOTPLUG);
> +}
> +
> +/**
> + * memblock_clear_hotplug - Clear flag MEMBLOCK_HOTPLUG for a specified region.
> + * @base: the base phys addr of the region
> + * @size: the size of the region
>    *
>    * Return 0 on succees, -errno on failure.
>    */
>   int __init_memblock memblock_clear_hotplug(phys_addr_t base, phys_addr_t size)
>   {
> -	struct memblock_type *type = &memblock.memory;
> -	int i, ret, start_rgn, end_rgn;
> -
> -	ret = memblock_isolate_range(type, base, size, &start_rgn, &end_rgn);
> -	if (ret)
> -		return ret;
> -
> -	for (i = start_rgn; i < end_rgn; i++)
> -		memblock_clear_region_flags(&type->regions[i],
> -					    MEMBLOCK_HOTPLUG);
> -
> -	memblock_merge_regions(type);
> -	return 0;
> +	return memblock_setclr_flag(base, size, 0, MEMBLOCK_HOTPLUG);
>   }
>   
>   /**
> 
> --
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> 


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