Message-ID: <4FB0C888.8070805@gmail.com>
Date: Mon, 14 May 2012 16:55:36 +0800
From: Cong Wang <xiyou.wangcong@gmail.com>
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To: Hugh Dickins <hughd@google.com>
CC: Andrew Morton <akpm@linux-foundation.org>,
        Christoph Hellwig <hch@infradead.org>,
        KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Alan Cox <alan@lxorguk.ukuu.org.uk>,
        Stephane Marchesin <marcheu@chromium.org>,
        Andi Kleen <andi@firstfloor.org>, Dave Airlie <airlied@gmail.com>,
        Daniel Vetter <ffwll.ch@google.com>, Rob Clark <rob.clark@linaro.org>,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/10] shmem: replace page if mapping excludes its zone
References: <alpine.LSU.2.00.1205120447380.28861@eggly.anvils> <alpine.LSU.2.00.1205120453210.28861@eggly.anvils>
In-Reply-To: <alpine.LSU.2.00.1205120453210.28861@eggly.anvils>
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On 05/12/2012 07:59 PM, Hugh Dickins wrote:
> +	VM_BUG_ON(!PageLocked(oldpage));
> +	__set_page_locked(newpage);
> +	VM_BUG_ON(!PageUptodate(oldpage));
> +	SetPageUptodate(newpage);
> +	VM_BUG_ON(!PageSwapBacked(oldpage));
> +	SetPageSwapBacked(newpage);
> +	VM_BUG_ON(!swap_index);
> +	set_page_private(newpage, swap_index);
> +	VM_BUG_ON(!PageSwapCache(oldpage));
> +	SetPageSwapCache(newpage);
> +

Are all of these VM_BUG_ON's necessary?
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