Re: [Qemu-block] [PATCH v12 8/9] qcow2: Set the default cache-clean-interval to 10 minutes

[Alberto Garcia]

On Thu 27 Sep 2018 05:53:34 PM CEST, Eric Blake wrote:
> On 9/26/18 11:04 AM, Leonid Bloch wrote:
>> The default cache-clean-interval is set to 10 minutes, in order to lower
>> the overhead of the qcow2 caches (before the default was 0, i.e.
>> disabled).
>> 
>> * For non-Linux platforms the default is kept at 0, because
>>    cache-clean-interval is not supported there yet.
>> 
>> Signed-off-by: Leonid Bloch <address@hidden>
>> Reviewed-by: Alberto Garcia <address@hidden>
>> Reviewed-by: Kevin Wolf <address@hidden>
>> ---
>
>> @@ -76,13 +76,15 @@
>>   
>>   #ifdef CONFIG_LINUX
>>   #define DEFAULT_L2_CACHE_MAX_SIZE S_32MiB
>> +#define DEFAULT_CACHE_CLEAN_INTERVAL 600  /* seconds */
>>   #else
>>   #define DEFAULT_L2_CACHE_MAX_SIZE S_8MiB
>> +/* Cache clean interval is currently available only on Linux, so must be 0 
>> */
>> +#define DEFAULT_CACHE_CLEAN_INTERVAL 0
>>   #endif
>>   
>
>> +++ b/docs/qcow2-cache.txt
>> @@ -210,8 +210,8 @@ This example removes all unused cache entries every 15 
>> minutes:
>>   
>>      -drive file=hd.qcow2,cache-clean-interval=900
>>   
>> -If unset, the default value for this parameter is 0 and it disables
>> -this feature.
>> +If unset, the default value for this parameter is 600. Setting it to 0
>> +disables this feature.
>
> Should this wording mention that the non-zero default is only on Linux
> (or rather, only on platforms where a non-zero value makes a
> difference)?

The next paragraph in the same document already says that this is a
Linux-only feature, so perhaps it's not so important.

Berto