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Date: Thu, 21 Dec 2023 04:35:46 +0000
From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	Ryan Roberts <ryan.roberts@arm.com>,
	Yin Fengwei <fengwei.yin@intel.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Muchun Song <muchun.song@linux.dev>, Peter Xu <peterx@redhat.com>
Subject: Re: [PATCH v2 03/40] mm/rmap: introduce and use
 hugetlb_add_file_rmap()
Message-ID: <ZYPAoq0mIje00j+U@casper.infradead.org>
References: <20231220224504.646757-1-david@redhat.com>
 <20231220224504.646757-4-david@redhat.com>
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In-Reply-To: <20231220224504.646757-4-david@redhat.com>

On Wed, Dec 20, 2023 at 11:44:27PM +0100, David Hildenbrand wrote:
> hugetlb rmap handling differs quite a lot from "ordinary" rmap code.
> For example, hugetlb currently only supports entire mappings, and treats
> any mapping as mapped using a single "logical PTE". Let's move it out
> of the way so we can overhaul our "ordinary" rmap.
> implementation/interface.
> 
> Right now we're using page_dup_file_rmap() in some cases where "ordinary"
> rmap code would have used page_add_file_rmap(). So let's introduce and
> use hugetlb_add_file_rmap() instead. We won't be adding a
> "hugetlb_dup_file_rmap()" functon for the fork() case, as it would be
> doing the same: "dup" is just an optimization for "add".
> 
> What remains is a single page_dup_file_rmap() call in fork() code.
> 
> Add sanity checks that we end up with the right folios in the right
> functions.
> 
> Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
> Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>