Re: [PATCH v9 1/8] drivers/base/memory: Introduce memory_block_{online,offline}

From: Michal Hocko <mhocko@suse.com>
To: Oscar Salvador <osalvador@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v9 1/8] drivers/base/memory: Introduce memory_block_{online,offline}
Date: Tue, 20 Apr 2021 11:23:08 +0200	[thread overview]
Message-ID: <YH6dfDbT56koiow6@dhcp22.suse.cz> (raw)
In-Reply-To: <20210416112411.9826-2-osalvador@suse.de>

On Fri 16-04-21 13:24:04, Oscar Salvador wrote:
> This is a preparatory patch that introduces two new functions:
> memory_block_online() and memory_block_offline().
> 
> For now, these functions will only call online_pages() and offline_pages()
> respectively, but they will be later in charge of preparing the vmemmap
> pages, carrying out the initialization and proper accounting of such
> pages.
> 
> Since memory_block struct contains all the information, pass this struct
> down the chain till the end functions.
> 
> Signed-off-by: Oscar Salvador <osalvador@suse.de>
> Reviewed-by: David Hildenbrand <david@redhat.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  drivers/base/memory.c | 33 +++++++++++++++++++++------------
>  1 file changed, 21 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index f35298425575..f209925a5d4e 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -169,30 +169,41 @@ int memory_notify(unsigned long val, void *v)
>  	return blocking_notifier_call_chain(&memory_chain, val, v);
>  }
>  
> +static int memory_block_online(struct memory_block *mem)
> +{
> +	unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
> +	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
> +
> +	return online_pages(start_pfn, nr_pages, mem->online_type, mem->nid);
> +}
> +
> +static int memory_block_offline(struct memory_block *mem)
> +{
> +	unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
> +	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
> +
> +	return offline_pages(start_pfn, nr_pages);
> +}
> +
>  /*
>   * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
>   * OK to have direct references to sparsemem variables in here.
>   */
>  static int
> -memory_block_action(unsigned long start_section_nr, unsigned long action,
> -		    int online_type, int nid)
> +memory_block_action(struct memory_block *mem, unsigned long action)
>  {
> -	unsigned long start_pfn;
> -	unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
>  	int ret;
>  
> -	start_pfn = section_nr_to_pfn(start_section_nr);
> -
>  	switch (action) {
>  	case MEM_ONLINE:
> -		ret = online_pages(start_pfn, nr_pages, online_type, nid);
> +		ret = memory_block_online(mem);
>  		break;
>  	case MEM_OFFLINE:
> -		ret = offline_pages(start_pfn, nr_pages);
> +		ret = memory_block_offline(mem);
>  		break;
>  	default:
>  		WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
> -		     "%ld\n", __func__, start_section_nr, action, action);
> +		     "%ld\n", __func__, mem->start_section_nr, action, action);
>  		ret = -EINVAL;
>  	}
>  
> @@ -210,9 +221,7 @@ static int memory_block_change_state(struct memory_block *mem,
>  	if (to_state == MEM_OFFLINE)
>  		mem->state = MEM_GOING_OFFLINE;
>  
> -	ret = memory_block_action(mem->start_section_nr, to_state,
> -				  mem->online_type, mem->nid);
> -
> +	ret = memory_block_action(mem, to_state);
>  	mem->state = ret ? from_state_req : to_state;
>  
>  	return ret;
> -- 
> 2.16.3

-- 
Michal Hocko
SUSE Labs