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Date: Wed, 20 Jul 2016 09:24:04 +0200
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH] mm/page_owner: Align with pageblock_nr pages
Message-ID: <20160720072404.GD11249@dhcp22.suse.cz>
References: <1468938136-24228-1-git-send-email-zhongjiang@huawei.com>
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To: iamjoonsoo.kim@lge.com, zhongjiang <zhongjiang@huawei.com>
Cc: akpm@linux-foundation.org, linux-mm@kvack.org

On Tue 19-07-16 22:22:16, zhongjiang wrote:
> From: zhong jiang <zhongjiang@huawei.com>
> 
> when pfn_valid(pfn) return false, pfn should be align with
> pageblock_nr_pages other than MAX_ORDER_NR_PAGES in
> init_pages_in_zone, because the skipped 2M may be valid pfn,
> as a result, early allocated count will not be accurate.

I really do not understand this changelog. I thought that
MAX_ORDER_NR_PAGES and pageblock_nr_pages are the same thing but they
might not be for HUGETLB. Should init_pages_in_zone depend on something
like HUGETLB? Is this even correct I would have expected that we should
initialize in the page block steps so MAX_ORDER_NR_PAGES. Could you
clarify Joonsoo, please?

> 
> Signed-off-by: zhong jiang <zhongjiang@huawei.com>
> ---
>  mm/page_owner.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index c6cda3e..aa2c486 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -310,7 +310,7 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
>  	 */
>  	for (; pfn < end_pfn; ) {
>  		if (!pfn_valid(pfn)) {
> -			pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
> +			pfn = ALIGN(pfn + 1, pageblock_nr_pages);
>  			continue;
>  		}
>  
> -- 
> 1.8.3.1

-- 
Michal Hocko
SUSE Labs

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