[libvirt] [PATCH v2] vz: allow to start vz driver without host cache info

[Mikhail Feoktistov]

On 11.07.2017 12:22, Martin Kletzander wrote:
> On Tue, Jul 11, 2017 at 04:59:05AM -0400, Mikhail Feoktistov wrote:
>> Show warning message instead of fail operation.
>> It happens if kernel or cpu doesn't support reporting cpu cache info.
>> In case of Virtuozzo file "id" doesn't exist.
>
> What is your kernel version?
>
  3.10.0-514.16.1.vz7.30.10
> Is there another way of getting the information about the cache ID?
> Maybe we need to parse the name of the cache directory 'index2' would be
> id 2 maybe?  If there is no other way, then this fix is fine (as most
> drivers do the same thing), but I would rather fix it if that's
> possible.  Unfortunately the cache information is structured stupidly
> compared to other kernel-provided topology-related information.
Only kernel 4.11 reports cache ID (maybe 4.10, but not checked)
4.9 doesn't report ID
ID doesn't match to indexN

[liveuser at localhost-live ~]$ uname -a
Linux localhost-live 4.11.0-2.fc26.x86_64 #1 SMP Tue May 9 15:24:49 UTC 
2017 x86_64 x86_64 x86_64 GNU/Linux
[liveuser at localhost-live ~]$ cat 
/sys/devices/system/cpu/cpu1/cache/index0/id
0
[liveuser at localhost-live ~]$ cat 
/sys/devices/system/cpu/cpu1/cache/index1/id
0
[liveuser at localhost-live ~]$ cat 
/sys/devices/system/cpu/cpu1/cache/index2/id
0
[liveuser at localhost-live ~]$ cat 
/sys/devices/system/cpu/cpu0/cache/index2/id
0
[liveuser at localhost-live ~]$ cat 
/sys/devices/system/cpu/cpu0/cache/index0/id
0

>> ---
>> src/vz/vz_driver.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/src/vz/vz_driver.c b/src/vz/vz_driver.c
>> index 6f4aee3..eb97e54 100644
>> --- a/src/vz/vz_driver.c
>> +++ b/src/vz/vz_driver.c
>> @@ -119,7 +119,7 @@ vzBuildCapabilities(void)
>>         goto error;
>>
>>     if (virCapabilitiesInitCaches(caps) < 0)
>> -        goto error;
>> +        VIR_WARN("Failed to get host CPU cache info");
>>
>>     verify(ARRAY_CARDINALITY(archs) == ARRAY_CARDINALITY(emulators));
>>
>> -- 
>> 1.8.3.1
>>
>> -- 
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