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Message-ID: <709b459a-3c71-49b1-7ac1-3144ae0fa89a@redhat.com>
Date:   Thu, 31 Mar 2022 10:55:13 +0200
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Subject: Re: [PATCH v2 1/3] mm: add vm_normal_lru_pages for LRU handled pages
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To:     Christoph Hellwig <hch@lst.de>, Alex Sierra <alex.sierra@amd.com>
Cc:     jgg@nvidia.com, Felix.Kuehling@amd.com, linux-mm@kvack.org,
        rcampbell@nvidia.com, linux-ext4@vger.kernel.org,
        linux-xfs@vger.kernel.org, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, jglisse@redhat.com,
        apopple@nvidia.com, willy@infradead.org, akpm@linux-foundation.org
References: <20220330212537.12186-1-alex.sierra@amd.com>
 <20220330212537.12186-2-alex.sierra@amd.com> <20220331085341.GA22102@lst.de>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20220331085341.GA22102@lst.de>
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On 31.03.22 10:53, Christoph Hellwig wrote:
>> -	page = vm_normal_page(vma, addr, pte);
>> +	page = vm_normal_lru_page(vma, addr, pte);
> 
> Why can't this deal with ZONE_DEVICE pages?  It certainly has
> nothing do with a LRU I think.  In fact being able to have
> stats that count say the number of device pages here would
> probably be useful at some point.
> 
> In general I find the vm_normal_lru_page vs vm_normal_page
> API highly confusing.  An explicit check for zone device pages
> in the dozen or so spots that care has a much better documentation
> value, especially if accompanied by comments where it isn't entirely
> obvious.

What's your thought on FOLL_LRU?

-- 
Thanks,

David / dhildenb