Re: [PATCH 7/8] Use xvmalloc to store compressed chunks

Minchan Kim
2010-07-19T04:36:45Z

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