Re: [PATCH v3 3/5] handle zcache_[eph|pers]_zpages for zero-filled page

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

On Sat, Mar 16, 2013 at 09:11:06AM -0400, Konrad Rzeszutek Wilk wrote:
>On Fri, Mar 15, 2013 at 10:34:18AM +0800, Wanpeng Li wrote:
>> Increment/decrement zcache_[eph|pers]_zpages for zero-filled pages,
>> the main point of the counters for zpages and pageframes is to be 
>> able to calculate density == zpages/pageframes. A zero-filled page 
>> becomes a zpage that "compresses" to zero bytes and, as a result, 
>> requires zero pageframes for storage. So the zpages counter should 
>> be increased but the pageframes counter should not.
>> 
>> [Dan Magenheimer <dan.magenheimer@oracle.com>: patch description]
>> Acked-by: Dan Magenheimer <dan.magenheimer@oracle.com>
>
>Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Thanks for your review Konrad. :-)

>> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>> ---
>>  drivers/staging/zcache/zcache-main.c |    7 ++++++-
>>  1 files changed, 6 insertions(+), 1 deletions(-)
>> 
>> diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c
>> index 6c35c7d..ef8c960 100644
>> --- a/drivers/staging/zcache/zcache-main.c
>> +++ b/drivers/staging/zcache/zcache-main.c
>> @@ -863,6 +863,8 @@ static int zcache_pampd_get_data_and_free(char *data, size_t *sizep, bool raw,
>>  	if (pampd == (void *)ZERO_FILLED) {
>>  		handle_zero_filled_page(data);
>>  		zero_filled = true;
>> +		zsize = 0;
>> +		zpages = 1;
>>  		if (!raw)
>>  			*sizep = PAGE_SIZE;
>>  		goto zero_fill;
>> @@ -917,8 +919,11 @@ static void zcache_pampd_free(void *pampd, struct tmem_pool *pool,
>>  
>>  	BUG_ON(preemptible());
>>  
>> -	if (pampd == (void *)ZERO_FILLED)
>> +	if (pampd == (void *)ZERO_FILLED) {
>>  		zero_filled = true;
>> +		zsize = 0;
>> +		zpages = 1;
>> +	}
>>  
>>  	if (pampd_is_remote(pampd) && !zero_filled) {
>>  
>> -- 
>> 1.7.7.6
>> 

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