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Subject: Re: [PATCH] mm: page_alloc: avoid false page outside zone error info
To:     Matthew Wilcox <willy@infradead.org>
CC:     <akpm@linux-foundation.org>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>
References: <20230704111823.940331-1-linmiaohe@huawei.com>
 <ZKQM2lg7524dIAQl@casper.infradead.org>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <feb41501-163a-58d6-1996-8d6ebc9d800e@huawei.com>
Date:   Tue, 4 Jul 2023 20:36:00 +0800
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On 2023/7/4 20:13, Matthew Wilcox wrote:
> On Tue, Jul 04, 2023 at 07:18:23PM +0800, Miaohe Lin wrote:
>> @@ -470,6 +470,8 @@ static int page_outside_zone_boundaries(struct zone *zone, struct page *page)
>>  		sp = zone->spanned_pages;
>>  		if (!zone_spans_pfn(zone, pfn))
>>  			ret = 1;
>> +		else
>> +			ret = 0;
> 
> Surely 'ret = zone_spans_pfn(zone, pfn);' ?

Do you mean 'ret = !zone_spans_pfn(zone, pfn);'?  This format looks fine to me.

> 
> Also, did you spot this by inspection or do you have a test-case or bug
> report?  Should this have a Fixes: tag?

This is from code inspection. The race window should be really small thus hard to trigger
in real world. And yes, it seems Fixes tag is a really ancient commit:

	Fixes: bdc8cb984576 ("[PATCH] memory hotplug locking: zone span seqlock")

Thanks for your comment and reply.