linux-kernel - Re: [PATCH] memblock: avoid some repeat when add new range

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Date:   Tue, 14 Jun 2022 15:52:48 +0800
From:   Yixun Lan <dlan@...too.org>
To:     tjytimi <tjytimi@....com>
Cc:     rppt@...nel.org, akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] memblock: avoid some repeat when add new range


On 10:41 Thu 09 Jun     , tjytimi wrote:
> The worst case is that the new memory range overlaps all existing
> regions,which need type->cnt + 1 free area of struct memblock_region.
> So if type->cnt + 1 + type->cnt is less than type->max,we can insert
> regions directly.And becase of merge operation in the end of function,
> tpye->cnt increase slowly for many cases.So this patch can avoid
> unnecessary repeat for many cases when add new memory range.
> 
> Signed-off-by: tjytimi <tjytimi@....com>
Can you fix the author/signed-off tag with your real legal name?

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v4.18#n460

> ---
>  mm/memblock.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/memblock.c b/mm/memblock.c
> index e4f03a6e8..243cd7de5 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -602,6 +602,9 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>  	base = obase;
>  	nr_new = 0;
>  
> +	if (type->cnt<<1 < type->max - 1)
> +		insert = true;
> +
>  	for_each_memblock_type(idx, type, rgn) {
>  		phys_addr_t rbase = rgn->base;
>  		phys_addr_t rend = rbase + rgn->size;
> -- 
> 2.32.0
> 

-- 
Yixun Lan (dlan)
Gentoo Linux Developer
GPG Key ID AABEFD55