Re: [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal

From: Oscar Salvador <osalvador@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: akpm@linux-foundation.org, Michal Hocko <mhocko@suse.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Logan Gunthorpe <logang@deltatee.com>,
	linux-mm@kvack.org, linux-nvdimm@lists.01.org,
	linux-kernel@vger.kernel.org, david@redhat.com
Subject: Re: [PATCH v6 04/12] mm/hotplug: Prepare shrink_{zone, pgdat}_span for sub-section removal
Date: Fri, 26 Apr 2019 15:59:12 +0200	[thread overview]
Message-ID: <20190426135907.GA30513@linux> (raw)
In-Reply-To: <155552635609.2015392.6246305135559796835.stgit@dwillia2-desk3.amr.corp.intel.com>

On Wed, Apr 17, 2019 at 11:39:16AM -0700, Dan Williams wrote:
> @@ -417,10 +417,10 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
>  	 * it check the zone has only hole or not.
>  	 */
>  	pfn = zone_start_pfn;
> -	for (; pfn < zone_end_pfn; pfn += PAGES_PER_SECTION) {
> +	for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUB_SECTION) {
>  		ms = __pfn_to_section(pfn);
>  
> -		if (unlikely(!valid_section(ms)))
> +		if (unlikely(!pfn_valid(pfn)))
>  			continue;
>  
>  		if (page_zone(pfn_to_page(pfn)) != zone)
> @@ -485,10 +485,10 @@ static void shrink_pgdat_span(struct pglist_data *pgdat,
>  	 * has only hole or not.
>  	 */
>  	pfn = pgdat_start_pfn;
> -	for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SECTION) {
> +	for (; pfn < pgdat_end_pfn; pfn += PAGES_PER_SUB_SECTION) {
>  		ms = __pfn_to_section(pfn);
>  
> -		if (unlikely(!valid_section(ms)))
> +		if (unlikely(!pfn_valid(pfn)))
>  			continue;
>  
>  		if (pfn_to_nid(pfn) != nid)

The last loop from shrink_{pgdat,zone}_span can be reworked to unify both
in one function, and both functions can be factored out a bit.
Actually, I do have a patch that does that, I might dig it up.

The rest looks good:

Reviewed-by: Oscar Salvador <osalvador@suse.de>

> 

-- 
Oscar Salvador
SUSE L3