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Date: Thu, 04 Jun 2015 11:44:40 -0700
From: Dave Hansen <dave.hansen@intel.com>
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To: Xishi Qiu <qiuxishi@huawei.com>, Andrew Morton <akpm@linux-foundation.org>,
        nao.horiguchi@gmail.com, Yinghai Lu <yinghai@kernel.org>,
        "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
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        Hanjun Guo <guohanjun@huawei.com>, "Luck, Tony" <tony.luck@intel.com>
CC: Linux MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 11/12] mm: add the PCP interface
References: <55704A7E.5030507@huawei.com> <55704CED.1020702@huawei.com>
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On 06/04/2015 06:04 AM, Xishi Qiu wrote:
>  	spin_lock(&zone->lock);
>  	for (i = 0; i < count; ++i) {
> -		struct page *page = __rmqueue(zone, order, migratetype);
> +		struct page *page;
> +
> +		if (is_migrate_mirror(migratetype))
> +			page = __rmqueue_smallest(zone, order, migratetype);
> +		else
> +			page = __rmqueue(zone, order, migratetype);
>  		if (unlikely(page == NULL))
>  			break;

Why is this necessary/helpful?  The changelog doesn't tell me either. :(

Why was this code modified in stead of putting the changes in
__rmqueue() itself (like CMA did)?