linux-kernel - Re: [PATCH v3 1/2] mm: pass page count and reserved to __init_single

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Message-ID: <9777812e-c8c8-2105-cd2c-443438786172@redhat.com>
Date:   Tue, 26 Sep 2023 09:44:32 +0200
From:   David Hildenbrand <david@...hat.com>
To:     Yajun Deng <yajun.deng@...ux.dev>, akpm@...ux-foundation.org,
        rppt@...nel.org
Cc:     mike.kravetz@...cle.com, muchun.song@...ux.dev,
        willy@...radead.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/2] mm: pass page count and reserved to
 __init_single_page

On 26.09.23 04:33, Yajun Deng wrote:
> When we init a single page, we need to mark this page reserved if it
> does. 

I failed to parse the last part of this sentence.

> And some pages may not need to set page count, such as compound
> pages.

Usually, the refcount of all tail pages *must* be zero. Otherwise, 
get_page_unless_zero() would work on tail pages.

Can you elaborate why it should be okay here?


-- 
Cheers,

David / dhildenb