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From: Michal Hocko <mhocko@kernel.org>
To: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: akpm@linux-foundation.org, osalvador@suse.de,
	dan.j.williams@intel.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, david@redhat.com
Subject: Re: [PATCH] mm/spase: never partially remove memmap for early section
Date: Tue, 23 Jun 2020 17:18:28 +0200	[thread overview]
Message-ID: <20200623151828.GA31426@dhcp22.suse.cz> (raw)
In-Reply-To: <20200623094258.6705-1-richard.weiyang@linux.alibaba.com>

On Tue 23-06-20 17:42:58, Wei Yang wrote:
> For early sections, we assumes its memmap will never be partially
> removed. But current behavior breaks this.
> 
> Let's correct it.
> 
> Fixes: ba72b4c8cf60 ("mm/sparsemem: support sub-section hotplug")
> Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>

Can a user trigger this or is this a theoretical bug?

> ---
>  mm/sparse.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index b2b9a3e34696..1a0069f492f5 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -825,10 +825,10 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages,
>  		ms->section_mem_map &= ~SECTION_HAS_MEM_MAP;
>  	}
>  
> -	if (section_is_early && memmap)
> -		free_map_bootmem(memmap);
> -	else
> +	if (!section_is_early)

This begs a comment.

>  		depopulate_section_memmap(pfn, nr_pages, altmap);
> +	else if (memmap)
> +		free_map_bootmem(memmap);
>  
>  	if (empty)
>  		ms->section_mem_map = (unsigned long)NULL;
> -- 
> 2.20.1 (Apple Git-117)
> 

-- 
Michal Hocko
SUSE Labs


  parent reply	other threads:[~2020-06-23 15:19 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23  9:42 [PATCH] mm/spase: never partially remove memmap for early section Wei Yang
2020-06-23 12:44 ` David Hildenbrand
2020-06-23 13:02   ` Wei Yang
2020-06-23 13:16     ` David Hildenbrand
2020-06-23 15:18 ` Michal Hocko [this message]
2020-06-23 21:48   ` Wei Yang
2020-06-24  6:13   ` Wei Yang
2020-06-24 16:10     ` Dan Williams
2020-06-24 22:05       ` Wei Yang
2020-06-24 22:20         ` Dan Williams
2020-06-24 22:44           ` Wei Yang
2020-06-24 23:47             ` Dan Williams
2020-06-25  5:53               ` David Hildenbrand
2020-06-25 19:46                 ` Dan Williams
2020-06-25 22:29                   ` Wei Yang
2020-06-29  8:34                   ` Wei Yang
2020-06-29 22:13                     ` Dan Williams
2020-06-29 22:58                       ` Wei Yang
2020-06-30  7:16                         ` David Hildenbrand
2020-06-25 22:39                 ` Wei Yang
2020-06-26  4:59                   ` David Hildenbrand
2020-06-24  7:48   ` David Hildenbrand
2020-06-24  8:04     ` David Hildenbrand
2020-06-24  8:13     ` Wei Yang
2020-06-24  8:41       ` David Hildenbrand
2020-06-24  8:50         ` Michal Hocko
2020-06-24 22:27         ` Wei Yang
2020-06-24  0:21 ` Dan Williams
2020-06-24  1:11   ` Wei Yang
2020-06-24  1:47   ` Baoquan He
2020-06-24  2:14     ` Baoquan He
2020-06-24  3:46     ` Wei Yang
2020-06-24  3:52       ` Baoquan He
2020-06-24  3:56         ` Wei Yang
2020-06-24  8:51           ` David Hildenbrand
2020-06-24 22:08             ` Wei Yang

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