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Date:   Tue, 5 Jul 2022 14:25:47 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Gang Li <ligang.bdlg@bytedance.com>
Cc:     Mike Kravetz <mike.kravetz@oracle.com>,
        Muchun Song <songmuchun@bytedance.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] mm, hugetlb: skip irrelevant nodes in
 show_free_areas()
Message-Id: <20220705142547.da3ea5a7383a7eeec3a93665@linux-foundation.org>
In-Reply-To: <20220705092120.2158-1-ligang.bdlg@bytedance.com>
References: <20220705092120.2158-1-ligang.bdlg@bytedance.com>
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On Tue,  5 Jul 2022 17:21:19 +0800 Gang Li <ligang.bdlg@bytedance.com> wrote:

> show_free_areas() allows to filter out node specific data which is
> irrelevant to the allocation request. But hugetlb_show_meminfo() still
> shows hugetlb on all nodes, which is redundant and unnecessary.
> 
> Use show_mem_node_skip() to skip irrelevant nodes. And replace
> hugetlb_show_meminfo() with hugetlb_show_meminfo_node(nid).

It would be helpful to include before-and-after sample output text in
the changelog to help others assess the proposed change.

> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6202,7 +6202,11 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
>  		printk(KERN_CONT "= %lukB\n", K(total));
>  	}
>  
> -	hugetlb_show_meminfo();
> +	for_each_online_node(nid) {
> +		if (show_mem_node_skip(filter, nid, nodemask))
> +			continue;
> +		hugetlb_show_meminfo_node(nid);
> +	}
>  

Does this mean that potentially useful info about presently-offline
nodes will no longer be available?