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Subject: Re: [RFC PATCH 0/3] hugetlb: add demote/split page functionality
To:     Mike Kravetz <mike.kravetz@oracle.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Cc:     Michal Hocko <mhocko@suse.com>, Oscar Salvador <osalvador@suse.de>,
        Zi Yan <ziy@nvidia.com>, David Rientjes <rientjes@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <20210309001855.142453-1-mike.kravetz@oracle.com>
 <29cb78c5-4fca-0f0a-c603-0c75f9f50d05@redhat.com>
 <ebb19eb5-ae9e-22f1-4e19-e5fce32c695c@oracle.com>
 <6c66c265-c9b9-ffe9-f860-f96f3485477e@redhat.com>
 <777d3771-7d2f-8e88-8496-56440e195a43@oracle.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <dfd59d83-7916-518d-23ce-a9a4e6781918@redhat.com>
Date:   Tue, 9 Mar 2021 20:01:29 +0100
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> I need to take a close look at Oscar's patches.  Too many thing to look
> at/review :)
> 
> This series does take into account gigantic pages allocated in CMA.
> Such pages can be demoted, and we need to track that they need to go
> back to CMA.  Nothing super special for this, mostly a new hugetlb
> specific flag to track such pages.

Ah, just spotted it - patch #2 :)

Took me a while to figure out that we end up calling 
cma_declare_contiguous_nid() with order_per_bit=0 - would have thought 
we would be using the actual smallest allocation order we end up using 
for huge/gigantic pages via CMA. Well, this way it "simply works".

-- 
Thanks,

David / dhildenb