linux-kernel - Re: [PATCH 2/2] make new alloc_pages

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Date:	Fri, 08 Apr 2011 14:28:47 +0200
From:	"Michal Nazarewicz" <mina86@...a86.com>
To:	linux-mm@...ck.org, "Dave Hansen" <dave@...ux.vnet.ibm.com>
Cc:	linux-kernel@...r.kernel.org, "Timur Tabi" <timur@...escale.com>,
	"Andi Kleen" <andi@...stfloor.org>, "Mel Gorman" <mel@....ul.ie>,
	"Andrew Morton" <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2/2] make new alloc_pages_exact()

On Thu, 07 Apr 2011 19:21:05 +0200, Dave Hansen <dave@...ux.vnet.ibm.com>  
wrote:
> +struct page *__alloc_pages_exact(gfp_t gfp_mask, size_t size)
>  {
>  	unsigned int order = get_order(size);
> -	unsigned long addr;
> +	struct page *page;
> -	addr = __get_free_pages(gfp_mask, order);
> -	if (addr) {
> -		unsigned long alloc_end = addr + (PAGE_SIZE << order);
> -		unsigned long used = addr + PAGE_ALIGN(size);
> +	page = alloc_pages(gfp_mask, order);
> +	if (page) {
> +		struct page *alloc_end = page + (1 << order);
> +		struct page *used = page + PAGE_ALIGN(size)/PAGE_SIZE;
> -		split_page(virt_to_page((void *)addr), order);
> +		split_page(page, order);
>  		while (used < alloc_end) {
> -			free_page(used);
> -			used += PAGE_SIZE;
> +			__free_page(used);
> +			used++;
>  		}

Have you thought about moving this loop to a separate function, ie.
_free_page_range(start, end)?  I'm asking because this loop appears
in two places and my CMA would also benefit from such a function.

>  	}
> -	return (void *)addr;
> +	return page;
> +}

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michal "mina86" Nazarewicz    (o o)
ooo +-----<email/xmpp: mnazarewicz@...gle.com>-----ooO--(_)--Ooo--
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