linux-kernel - Re: [PATCH 2/5] mm: page_owner: add support for splitting to any order in split page

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Date:   Fri, 24 Mar 2023 16:17:17 +0100
From:   Michal Koutný <mkoutny@...e.com>
To:     Zi Yan <ziy@...dia.com>
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Yang Shi <shy828301@...il.com>, Yu Zhao <yuzhao@...gle.com>,
        linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH 2/5] mm: page_owner: add support for splitting to any
 order in split page_owner.

Hello.

On Mon, Mar 20, 2023 at 08:48:26PM -0400, Zi Yan <zi.yan@...t.com> wrote:
> @@ -5746,8 +5746,8 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
>  		struct page *page = virt_to_page((void *)addr);
>  		struct page *last = page + nr;
>  
> -		split_page_owner(page, 1 << order);
> -		split_page_memcg(page, 1 << order);
> +		split_page_owner(page, 1 << order, 1);
> +		split_page_memcg(page, 1 << order, 1);

I think here should be

> +		split_page_owner(page, order, 0);
> +		split_page_memcg(page, 1 << order, 1);

because I was wondering why split_page_memcg() doesn't use orders too?
(E.g. it wouldn't work well if nr % new_new != 0).

Thanks,
Michal

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