linux-kernel - Re: [PATCH v1 2/6] mm/rmap: move SetPageAnonExclusive out of __page_set_anon

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Message-ID: <ZQHH6ZC9aHQaqlNJ@casper.infradead.org>
Date:   Wed, 13 Sep 2023 15:32:09 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     David Hildenbrand <david@...hat.com>
Cc:     linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Muchun Song <muchun.song@...ux.dev>
Subject: Re: [PATCH v1 2/6] mm/rmap: move SetPageAnonExclusive out of
 __page_set_anon_rmap()

On Wed, Sep 13, 2023 at 02:51:09PM +0200, David Hildenbrand wrote:
> @@ -1246,11 +1241,13 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
>  
>  	if (likely(!folio_test_ksm(folio))) {
>  		if (first)
> -			__page_set_anon_rmap(folio, page, vma, address,
> -					     !!(flags & RMAP_EXCLUSIVE));
> +			__folio_set_anon(folio, vma, address,
> +					 !!(flags & RMAP_EXCLUSIVE));
>  		else
>  			__page_check_anon_rmap(folio, page, vma, address);
>  	}
> +	if (flags & RMAP_EXCLUSIVE)
> +		SetPageAnonExclusive(page);

Won't we end up setting AnonExclusive on ksm pages, or do we make sure
to never pass RMAP_EXCLUSIVE for ksm pages?

Maybe better to move these last two lines inside the previous test,
just to avoid the question.