linux-kernel - Re: [PATCH v2] mm/sparse: use MEMBLOCK_ALLOC

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Message-ID: <20240611021421.seknuy7flwztan33@master>
Date: Tue, 11 Jun 2024 02:14:21 +0000
From: Wei Yang <richard.weiyang@...il.com>
To: Leesoo Ahn <lsahn@...eel.net>
Cc: rppt@...nel.org, Leesoo Ahn <lsahn@...akecorp.com>,
	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm/sparse: use MEMBLOCK_ALLOC_ACCESSIBLE enum instead
 of 0

On Tue, Jun 11, 2024 at 12:15:28AM +0900, Leesoo Ahn wrote:
>Setting 'limit' variable to 0 might seem like it means "no limit". But
>in the memblock API, 0 actually means the 'MEMBLOCK_ALLOC_ACCESSIBLE'
>enum, which limits the physical address range end based on
>'memblock.current_limit'. This could be confusing.
>
>Use the enum instead of 0 to make it clear.
>
>Signed-off-by: Leesoo Ahn <lsahn@...eel.net>

Reviewed-by: Wei Yang <richard.weiyang@...il.com>

>---
>v1 -> v2: do not rename 'limit' to 'limit_or_flag'
>---
> mm/sparse.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/mm/sparse.c b/mm/sparse.c
>index de40b2c73406..cf93abc542ca 100644
>--- a/mm/sparse.c
>+++ b/mm/sparse.c
>@@ -351,7 +351,7 @@ sparse_early_usemaps_alloc_pgdat_section(struct pglist_data *pgdat,
> again:
> 	usage = memblock_alloc_try_nid(size, SMP_CACHE_BYTES, goal, limit, nid);
> 	if (!usage && limit) {
>-		limit = 0;
>+		limit = MEMBLOCK_ALLOC_ACCESSIBLE;
> 		goto again;
> 	}
> 	return usage;
>-- 
>2.34.1
>

-- 
Wei Yang
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