linux-kernel - Re: [PATCH] mm/madvise: replace with page_size() in madvise_inject

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Message-ID: <alpine.DEB.2.21.1911061327550.155572@chino.kir.corp.google.com>
Date:   Wed, 6 Nov 2019 13:28:11 -0800 (PST)
From:   David Rientjes <rientjes@...gle.com>
To:     Yunfeng Ye <yeyunfeng@...wei.com>
cc:     akpm@...ux-foundation.org, jgg@...pe.ca, mhocko@...e.com,
        jglisse@...hat.com, minchan@...nel.org, peterz@...radead.org,
        jack@...e.cz, rppt@...ux.ibm.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        "hushiyuan@...wei.com" <hushiyuan@...wei.com>,
        "linfeilong@...wei.com" <linfeilong@...wei.com>
Subject: Re: [PATCH] mm/madvise: replace with page_size() in
 madvise_inject_error()

On Wed, 6 Nov 2019, Yunfeng Ye wrote:

> The function page_size() is supported after the commit a50b854e073c
> ("mm: introduce page_size()").
> 
> Replace with page_size() in madvise_inject_error() for readability.
> 
> Signed-off-by: Yunfeng Ye <yeyunfeng@...wei.com>
> ---
>  mm/madvise.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 2be9f3fdb05e..38c4e7fcf850 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -856,13 +856,13 @@ static int madvise_inject_error(int behavior,
>  {
>  	struct page *page;
>  	struct zone *zone;
> -	unsigned int order;
> +	unsigned int size;

Should be unsinged long.

> 
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EPERM;
> 
> 
> -	for (; start < end; start += PAGE_SIZE << order) {
> +	for (; start < end; start += size) {
>  		unsigned long pfn;
>  		int ret;
> 
> @@ -874,9 +874,9 @@ static int madvise_inject_error(int behavior,
>  		/*
>  		 * When soft offlining hugepages, after migrating the page
>  		 * we dissolve it, therefore in the second loop "page" will
> -		 * no longer be a compound page, and order will be 0.
> +		 * no longer be a compound page.
>  		 */
> -		order = compound_order(compound_head(page));
> +		size = page_size(compound_head(page));
> 
>  		if (PageHWPoison(page)) {
>  			put_page(page);