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Subject: Re: [PATCH 3/5] mm, memory_hotplug: drop pointless block alignment
 checks from __offline_pages
To:     Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Oscar Salvador <OSalvador@suse.com>, Baoquan He <bhe@redhat.com>,
        linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
        Michal Hocko <mhocko@suse.com>
References: <20181116083020.20260-1-mhocko@kernel.org>
 <20181116083020.20260-4-mhocko@kernel.org>
From:   Anshuman Khandual <anshuman.khandual@arm.com>
Message-ID: <50a2cbeb-9d1b-d629-6390-c0b3d26f2d72@arm.com>
Date:   Fri, 16 Nov 2018 17:26:41 +0530
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On 11/16/2018 02:00 PM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@suse.com>
> 
> This function is never called from a context which would provide
> misaligned pfn range so drop the pointless check.
> 
> Signed-off-by: Michal Hocko <mhocko@suse.com>
> ---
>  mm/memory_hotplug.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 2b2b3ccbbfb5..a92b1b8f6218 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1554,12 +1554,6 @@ static int __ref __offline_pages(unsigned long start_pfn,
>  	struct zone *zone;
>  	struct memory_notify arg;
>  
> -	/* at least, alignment against pageblock is necessary */
> -	if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
> -		return -EINVAL;
> -	if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
> -		return -EINVAL;
> -
>  	mem_hotplug_begin();
>  
>  	/* This makes hotplug much easier...and readable.
> 

Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>