linux-kernel - Re: [PATCH 1/3] memory-hotplug: add move_pfn

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Date:	Tue, 10 May 2016 09:47:23 -0700 (PDT)
From:	Yasuaki Ishimatsu <yasu.isimatu@...il.com>
To:	Reza Arbab <arbab@...ux.vnet.ibm.com>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Daniel Kiper <daniel.kiper@...cle.com>,
	Dan Williams <dan.j.williams@...el.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Tang Chen <tangchen@...fujitsu.com>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	David Vrabel <david.vrabel@...rix.com>,
	Vitaly Kuznetsov <vkuznets@...hat.com>,
	David Rientjes <rientjes@...gle.com>,
	Andrew Banman <abanman@....com>,
	Chen Yucong <slaoub@...il.com>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] memory-hotplug: add move_pfn_range()


On Mon,  9 May 2016 12:53:37 -0500
Reza Arbab <arbab@...ux.vnet.ibm.com> wrote:

> Add move_pfn_range(), a wrapper to call move_pfn_range_left() or
> move_pfn_range_right().
> 
> No functional change. This will be utilized by a later patch.
> 
> Signed-off-by: Reza Arbab <arbab@...ux.vnet.ibm.com>

Looks good to me.
Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>

Thanks,
Yasuaki Ishimatsu

> ---
>  mm/memory_hotplug.c | 38 ++++++++++++++++++++++++++++----------
>  1 file changed, 28 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index aa34431..6b4b005 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -434,6 +434,25 @@ out_fail:
>  	return -1;
>  }
>  
> +static struct zone * __meminit move_pfn_range(int zone_shift,
> +		unsigned long start_pfn, unsigned long end_pfn)
> +{
> +	struct zone *zone = page_zone(pfn_to_page(start_pfn));
> +	int ret = 0;
> +
> +	if (zone_shift < 0)
> +		ret = move_pfn_range_left(zone + zone_shift, zone,
> +					  start_pfn, end_pfn);
> +	else if (zone_shift)
> +		ret = move_pfn_range_right(zone, zone + zone_shift,
> +					   start_pfn, end_pfn);
> +
> +	if (ret)
> +		return NULL;
> +
> +	return zone + zone_shift;
> +}
> +
>  static void __meminit grow_pgdat_span(struct pglist_data *pgdat, unsigned long start_pfn,
>  				      unsigned long end_pfn)
>  {
> @@ -1024,6 +1043,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
>  	int nid;
>  	int ret;
>  	struct memory_notify arg;
> +	int zone_shift = 0;
>  
>  	/*
>  	 * This doesn't need a lock to do pfn_to_page().
> @@ -1038,18 +1058,16 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
>  		return -EINVAL;
>  
>  	if (online_type == MMOP_ONLINE_KERNEL &&
> -	    zone_idx(zone) == ZONE_MOVABLE) {
> -		if (move_pfn_range_left(zone - 1, zone, pfn, pfn + nr_pages))
> -			return -EINVAL;
> -	}
> +	    zone_idx(zone) == ZONE_MOVABLE)
> +		zone_shift = -1;
> +
>  	if (online_type == MMOP_ONLINE_MOVABLE &&
> -	    zone_idx(zone) == ZONE_MOVABLE - 1) {
> -		if (move_pfn_range_right(zone, zone + 1, pfn, pfn + nr_pages))
> -			return -EINVAL;
> -	}
> +	    zone_idx(zone) == ZONE_MOVABLE - 1)
> +		zone_shift = 1;
>  
> -	/* Previous code may changed the zone of the pfn range */
> -	zone = page_zone(pfn_to_page(pfn));
> +	zone = move_pfn_range(zone_shift, pfn, pfn + nr_pages);
> +	if (!zone)
> +		return -EINVAL;
>  
>  	arg.start_pfn = pfn;
>  	arg.nr_pages = nr_pages;
> -- 
> 1.8.3.1
> 
> --
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