linux-kernel - Re: [PATCH V2 2/6] mm/sparse: free section usage memory in case populate_section

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Message-ID: <953557a5-f5cf-8780-ec60-73bff418650e@redhat.com>
Date:   Tue, 1 Jun 2021 10:19:23 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Dong Aisheng <aisheng.dong@....com>, linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org, dongas86@...il.com,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Rapoport <rppt@...nel.org>
Subject: Re: [PATCH V2 2/6] mm/sparse: free section usage memory in case
 populate_section_memmap failed

On 31.05.21 11:19, Dong Aisheng wrote:
> Free section usage memory in case populate_section_memmap failed.
> We use map_count to track the remain unused memory to be freed.
> 
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: Mike Rapoport <rppt@...nel.org>
> Signed-off-by: Dong Aisheng <aisheng.dong@....com>
> ---
> ChangeLog:
> v1->v2:
>   * using goto + lable according to Mike's suggestion
> ---
>   mm/sparse.c | 11 +++++++----
>   1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 7ac481353b6b..408b737e168e 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -533,7 +533,7 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
>   			mem_section_usage_size() * map_count);
>   	if (!usage) {
>   		pr_err("%s: node[%d] usemap allocation failed", __func__, nid);
> -		goto failed;
> +		goto failed1;
>   	}
>   	sparse_buffer_init(map_count * section_map_size(), nid);
>   	for_each_present_section_nr(pnum_begin, pnum) {
> @@ -548,17 +548,20 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
>   			pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.",
>   			       __func__, nid);
>   			pnum_begin = pnum;
> -			sparse_buffer_fini();
> -			goto failed;
> +			goto failed2;
>   		}
>   		check_usemap_section_nr(nid, usage);
>   		sparse_init_one_section(__nr_to_section(pnum), pnum, map, usage,
>   				SECTION_IS_EARLY);
>   		usage = (void *) usage + mem_section_usage_size();
> +		map_count--;
>   	}
>   	sparse_buffer_fini();
>   	return;
> -failed:
> +failed2:
> +	sparse_buffer_fini();
> +	memblock_free_early(__pa(usage), map_count * mem_section_usage_size());
> +failed1:
>   	/* We failed to allocate, mark all the following pnums as not present */
>   	for_each_present_section_nr(pnum_begin, pnum) {
>   		struct mem_section *ms;
> 

I still don't think we need this. Did you even manage to trigger this to 
test your patch?

-- 
Thanks,

David / dhildenb