linux-kernel - Re: [PATCH] mm/isolation: Remove redundant pfn_valid_within() in __first_valid

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Date:   Fri, 22 Mar 2019 10:23:47 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Anshuman Khandual <anshuman.khandual@....com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        mike.kravetz@...cle.com, zi.yan@...rutgers.edu, osalvador@...e.de,
        akpm@...ux-foundation.org
Subject: Re: [PATCH] mm/isolation: Remove redundant pfn_valid_within() in
 __first_valid_page()

On Thu 21-03-19 09:43:15, Anshuman Khandual wrote:
> pfn_valid_within() calls pfn_valid() when CONFIG_HOLES_IN_ZONE making it
> redundant for both definitions (w/wo CONFIG_MEMORY_HOTPLUG) of the helper
> pfn_to_online_page() which either calls pfn_valid() or pfn_valid_within().
> pfn_valid_within() being 1 when !CONFIG_HOLES_IN_ZONE is irrelevant either
> way. This does not change functionality.
> 
> Fixes: 2ce13640b3f4 ("mm: __first_valid_page skip over offline pages")
> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>

Forgot about
Acked-by: Michal Hocko <mhocko@...e.com>

> ---
>  mm/page_isolation.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index ce323e56b34d..d9b02bb13d60 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -150,8 +150,6 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
>  	for (i = 0; i < nr_pages; i++) {
>  		struct page *page;
>  
> -		if (!pfn_valid_within(pfn + i))
> -			continue;
>  		page = pfn_to_online_page(pfn + i);
>  		if (!page)
>  			continue;
> -- 
> 2.20.1
> 

-- 
Michal Hocko
SUSE Labs