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Message-ID: <b01d66f5-67c9-95a4-7dc7-ec7645560214@redhat.com>
Date:   Tue, 21 Jun 2022 09:39:31 +0200
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Subject: Re: [PATCH v5 1/2] mm: memory_hotplug: enumerate all supported
 section flags
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To:     Muchun Song <songmuchun@bytedance.com>, akpm@linux-foundation.org,
        corbet@lwn.net, mike.kravetz@oracle.com, osalvador@suse.de,
        paulmck@kernel.org
Cc:     linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, duanxiongchun@bytedance.com, smuchun@gmail.com
References: <20220620110616.12056-1-songmuchun@bytedance.com>
 <20220620110616.12056-2-songmuchun@bytedance.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20220620110616.12056-2-songmuchun@bytedance.com>
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On 20.06.22 13:06, Muchun Song wrote:
> We are almost running out of section flags, only one bit is available in
> the worst case (powerpc with 256k pages).  However, there are still some
> free bits (in ->section_mem_map) on other architectures (e.g. x86_64 has
> 10 bits available, arm64 has 8 bits available with worst case of 64K
> pages).  We have hard coded those numbers in code, it is inconvenient to
> use those bits on other architectures except powerpc.  So transfer those
> section flags to enumeration to make it easy to add new section flags in
> the future. Also, move SECTION_TAINT_ZONE_DEVICE into the scope of
> CONFIG_ZONE_DEVICE to save a bit on non-zone-device case.
> 
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb