Message-ID: <970ca2a4-416d-7e8f-37c7-510c5b050f4b@redhat.com>
Date:   Wed, 12 Jan 2022 12:04:30 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101
 Thunderbird/91.4.0
Subject: Re: [RFC PATCH v3 3/8] mm: migrate: allocate the right size of non
 hugetlb or THP compound pages.
Content-Language: en-US
To:     Zi Yan <ziy@nvidia.com>, linux-mm@kvack.org
Cc:     linux-kernel@vger.kernel.org,
        Michael Ellerman <mpe@ellerman.id.au>,
        Christoph Hellwig <hch@lst.de>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        linuxppc-dev@lists.ozlabs.org,
        virtualization@lists.linux-foundation.org,
        iommu@lists.linux-foundation.org, Vlastimil Babka <vbabka@suse.cz>,
        Mel Gorman <mgorman@techsingularity.net>,
        Eric Ren <renzhengeek@gmail.com>
References: <20220105214756.91065-1-zi.yan@sent.com>
 <20220105214756.91065-4-zi.yan@sent.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20220105214756.91065-4-zi.yan@sent.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 05.01.22 22:47, Zi Yan wrote:
> From: Zi Yan <ziy@nvidia.com>
> 
> alloc_migration_target() is used by alloc_contig_range() and non-LRU
> movable compound pages can be migrated. Current code does not allocate the
> right page size for such pages. Check THP precisely using
> is_transparent_huge() and add allocation support for non-LRU compound
> pages.

IIRC, we don't have any non-lru migratable pages that are coumpound
pages. Read: not used and not supported :)

Why is this required in the context of this series?


-- 
Thanks,

David / dhildenb