[libvirt] [PATCH 02/13] Introduce the function virCgroupMoveTask
tangchen
tangchen at cn.fujitsu.com
Tue Jul 10 09:27:59 UTC 2012
hi~
>> +int virCgroupMoveTask(virCgroupPtr src_group, virCgroupPtr dest_group)
>> +{
>> + int rc = 0;
>> + int i;
>> + char *content, *value, *next;
>> +
>> + for (i = 0 ; i < VIR_CGROUP_CONTROLLER_LAST ; i++) {
>> + /* Skip over controllers not mounted */
>> + if (!src_group->controllers[i].mountPoint ||
>> + !dest_group->controllers[i].mountPoint)
>> + continue;
>
> Should we insist that src_group and dest_group have the same set of
> mounted controllers? I'm worried that if we call this function, but the
> set of mounted controllers differs between the two sets, then we end up
> moving processes between some controllers and stranding them in the
> source for the remaining controllers.
>
True. So I change it to move tasks under one controller, and leave all the
other controller unmodified. You can see it in my new patch. :)
As you know, different cgroups are independent to each other. So I think
operate on only one controller will make sense.
>> + *next = '\0';
>> + if ((rc = virCgrouAddTaskStr(dest_group, value) < 0))
>> + goto cleanup;
>> + value = next + 1;
>> + }
>> + if (*value != '\0') {
>> + if ((rc = virCgrouAddTaskStr(dest_group, value) < 0))
>
> Does it make sense to parse all the string into integers, just to format
> the integers back into strings? Or would it be simpler to just cat the
> contents of the 'tasks' file from the source into the destination
> without bothering to interpret the date in transit?
>
I have tried this. But it seems that tasks file includes "\n", so it won't work.
>> + goto cleanup;
>> + }
>> +
>> + VIR_FREE(content);
>> + }
>> +
>> + return 0;
>> +
>> +cleanup:
>> + virCgroupMoveTask(dest_group, src_group);
>
> Is this cleanup always correct, or is it only correct if 'dest_group'
> started life empty? Should we at least log a warning message if a move
> was partially attempted and then reverted, particularly if the reversion
> attempt failed?
>
The cleanup way is also changed, please refer to my new patches.
Thanks. :)
--
Best Regards,
Tang chen
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