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Date: Mon, 19 Jul 2010 13:36:42 +0900
Message-ID: <AANLkTinjJLaDVenwNcxgN7ycr97XLN_DVi1ckXBZetZm@mail.gmail.com>
Subject: Re: [PATCH 7/8] Use xvmalloc to store compressed chunks
From: Minchan Kim <minchan.kim@gmail.com>
To: ngupta@vflare.org
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
        Hugh Dickins <hugh.dickins@tiscali.co.uk>,
        Andrew Morton <akpm@linux-foundation.org>, Greg KH <greg@kroah.com>,
        Dan Magenheimer <dan.magenheimer@oracle.com>,
        Rik van Riel <riel@redhat.com>, Avi Kivity <avi@redhat.com>,
        Christoph Hellwig <hch@infradead.org>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        linux-mm <linux-mm@kvack.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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Hi Nitin,

On Sun, Jul 18, 2010 at 5:21 PM, Nitin Gupta <ngupta@vflare.org> wrote:
> On 07/18/2010 01:23 PM, Pekka Enberg wrote:
>> Nitin Gupta wrote:
>>> @@ -528,17 +581,32 @@ static int zcache_store_page(struct zcache_inode_rb *znode,
>>> ? ? ? ? ?goto out;
>>> ? ? ?}
>>>
>>> - ? ?dest_data = kmap_atomic(zpage, KM_USER0);
>>> + ? ?local_irq_save(flags);
>>
>> Does xv_malloc() required interrupts to be disabled? If so, why doesn't the function do it by itself?
>>
>
>
> xvmalloc itself doesn't require disabling interrupts but zcache needs that since
> otherwise, we can have deadlock between xvmalloc pool lock and mapping->tree_lock
> which zcache_put_page() is called. OTOH, zram does not require this disabling of
> interrupts. So, interrupts are disable separately for zcache case.

cleancache_put_page always is called with spin_lock_irq.
Couldn't we replace spin_lock_irq_save with spin_lock?

-- 
Kind regards,
Minchan Kim
--
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