[libvirt] [PATCHv5 06/19] util: Add monitor interface to determine path

[John Ferlan]

On 10/10/18 9:56 AM, Wang, Huaqiang wrote:
> 
>> -----Original Message-----
>> From: John Ferlan [mailto:jferlan at redhat.com]
>> Sent: Wednesday, October 10, 2018 7:16 AM
>> To: Wang, Huaqiang <huaqiang.wang at intel.com>; libvir-list at redhat.com
>> Cc: Feng, Shaohe <shaohe.feng at intel.com>; Niu, Bing <bing.niu at intel.com>;
>> Ding, Jian-feng <jian-feng.ding at intel.com>; Zang, Rui <rui.zang at intel.com>
>> Subject: Re: [libvirt] [PATCHv5 06/19] util: Add monitor interface to determine
>> path
>>
>>
>>
>> On 10/9/18 6:30 AM, Wang Huaqiang wrote:
>>> Add interface for resctrl monitor to determine the path.
>>>
>>> Signed-off-by: Wang Huaqiang <huaqiang.wang at intel.com>
>>> ---
>>>  src/libvirt_private.syms |  1 +
>>>  src/util/virresctrl.c    | 32 ++++++++++++++++++++++++++++++++
>>>  src/util/virresctrl.h    |  3 +++
>>>  3 files changed, 36 insertions(+)
>>>
>>> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index
>>> 4a52a86..e175c8b 100644
>>> --- a/src/libvirt_private.syms
>>> +++ b/src/libvirt_private.syms
>>> @@ -2681,6 +2681,7 @@ virResctrlInfoGetMonitorPrefix;
>>> virResctrlInfoMonFree;  virResctrlInfoNew;  virResctrlMonitorAddPID;
>>> +virResctrlMonitorDeterminePath;
>>>  virResctrlMonitorNew;
>>>
>>>
>>> diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c index
>>> 03001cc..1a5578e 100644
>>> --- a/src/util/virresctrl.c
>>> +++ b/src/util/virresctrl.c
>>> @@ -2465,3 +2465,35 @@ virResctrlMonitorAddPID(virResctrlMonitorPtr
>>> monitor,  {
>>>      return virResctrlAddPID(monitor->path, pid);  }
>>> +
>>> +int
>>> +virResctrlMonitorDeterminePath(virResctrlMonitorPtr monitor,
>>> +                               const char *machinename) {
>>> +    char *alloc_path = NULL;
>>
>> const char
> 
> OK, a pointer to const char will be better.
> 
>>
>>> +    char *parentpath = NULL;
>>
>> VIR_AUTOFREE(char *) parentpath = NULL;
>>
>> (thus the VIR_FREE later isn't necessary)
> 
> I haven't realized the existence of such kind of variable 'decorator'.
> VIR_AUTOFREE will be used in next update.
> Thanks.
> 

Yeah it's "newer" stuff, but it hasn't always gotten into my review
cadence so sometimes I remember, sometimes I don't. We had a Google
summer of code student working through those changes, but there's still
many more places to change.

John

>>
>>> +
>>> +    if (!monitor) {
>>> +        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
>>> +                       _("Invalid resctrl monitor"));
>>> +        return -1;
>>> +    }
>>
>> Shouldn't there be a monitor->path check here like there is in
>> virResctrlAllocDeterminePath?
> 
> Since virResctrlAllocDeterminePath has such kind of safety check.
> Let's add the similar check here.
> will be added.
> 
>>
>>> +
>>> +    if (monitor->alloc)
>>> +        alloc_path = monitor->alloc->path;
>>> +    else
>>> +        alloc_path = (char *)SYSFS_RESCTRL_PATH;
>>
>> s/(char *)//
> 
> Will be removed.
> 
>>
>>> +
>>> +    if (virAsprintf(&parentpath, "%s/mon_groups", alloc_path) < 0)
>>> +        return -1;
>>> +
>>> +    monitor->path = virResctrlDeterminePath(parentpath, machinename,
>>> +                                            monitor->id);
>>> +
>>> +    VIR_FREE(parentpath);
>>
>> see above...
> 
> Line will be removed.
> 
>>
>> John
> 
> Thanks for review.
> Huaqiang
> 
>>
>>> +
>>> +    if (!monitor->path)
>>> +        return -1;
>>> +
>>> +    return 0;
>>> +}
>>> diff --git a/src/util/virresctrl.h b/src/util/virresctrl.h index
>>> cb9bfae..69b6b1d 100644
>>> --- a/src/util/virresctrl.h
>>> +++ b/src/util/virresctrl.h
>>> @@ -196,4 +196,7 @@ virResctrlMonitorNew(void);  int
>>> virResctrlMonitorAddPID(virResctrlMonitorPtr monitor,
>>>                          pid_t pid);
>>> +int
>>> +virResctrlMonitorDeterminePath(virResctrlMonitorPtr monitor,
>>> +                               const char *machinename);
>>>  #endif /*  __VIR_RESCTRL_H__ */
>>>
>