Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Fri, 1 May 2020 05:22:45 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     js1304@gmail.com
Cc:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
        Laura Abbott <labbott@redhat.com>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Michal Hocko <mhocko@suse.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <guro@fb.com>, Minchan Kim <minchan@kernel.org>,
        Rik van Riel <riel@surriel.com>,
        Christian Koenig <christian.koenig@amd.com>,
        Huang Rui <ray.huang@amd.com>,
        Eric Biederman <ebiederm@xmission.com>,
        "Rafael J . Wysocki" <rjw@rjwysocki.net>,
        Pavel Machek <pavel@ucw.cz>, kernel-team@lge.com,
        Christoph Hellwig <hch@infradead.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH v2 04/10] power: separate PageHighMem() and
 PageHighMemZone() use case
Message-ID: <20200501122245.GA21897@infradead.org>
References: <1588130803-20527-1-git-send-email-iamjoonsoo.kim@lge.com>
 <1588130803-20527-5-git-send-email-iamjoonsoo.kim@lge.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <1588130803-20527-5-git-send-email-iamjoonsoo.kim@lge.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Wed, Apr 29, 2020 at 12:26:37PM +0900, js1304@gmail.com wrote:
> index 6598001..be759a6 100644
> --- a/kernel/power/snapshot.c
> +++ b/kernel/power/snapshot.c
> @@ -1227,7 +1227,7 @@ static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
>  	if (!page || page_zone(page) != zone)
>  		return NULL;
>  
> -	BUG_ON(!PageHighMem(page));
> +	BUG_ON(!PageHighMemZone(page));

The above check already checks for the highmem zone.  So if we want
to keep the BUG_ON it needs stay PageHighMem to make sense.  That being
said I'd rather remove it entirelẏ.

> -	BUG_ON(PageHighMem(page));
> +	BUG_ON(PageHighMemZone(page));

Same here.

> @@ -1529,7 +1529,7 @@ static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
>  		if (!page)
>  			break;
>  		memory_bm_set_bit(&copy_bm, page_to_pfn(page));
> -		if (PageHighMem(page))
> +		if (PageHighMemZone(page))
>  			alloc_highmem++;
>  		else
>  			alloc_normal++;

I don't fully understand the log here.  Can Pavel or Rafael clarify
why swsupst would care about the exact zone?