[lxc-devel] [PATCH] cgroup.c: clean up for handle_cgroup_settings

[Qiang Huang]

On 2014/1/23 10:55, Serge Hallyn wrote:
> Quoting Qiang Huang (h.huangqiang at huawei.com):
>> Ping...
>>
>> Hi Serge or Stéphane,
>>
>> Did you miss this?
> 
> Patch looks good,
> 
> Acked-by: Serge E. Hallyn <serge.hallyn at ubuntu.com>
> 
> but note that the there's been a touch of churn there.  If ok with
> you I'll apply your patch with the needed changes;  if you prefer to

Feel free to adjust it.
Thanks.

> send a new patch let me know.
> 
>> On 2014/1/20 16:37, Qiang Huang wrote:
>>> Clean up the nesting if, make the logic similar for memory
>>> and cpuset, and the error message should sent from inside,
>>> for better extendibility.
>>>
>>> Signed-off-by: Qiang Huang <h.huangqiang at huawei.com>
>>> ---
>>>  src/lxc/cgroup.c | 53 ++++++++++++++++++++++++++++++++++-------------------
>>>  1 file changed, 34 insertions(+), 19 deletions(-)
>>>
>>> diff --git a/src/lxc/cgroup.c b/src/lxc/cgroup.c
>>> index 85384fc..693db94 100644
>>> --- a/src/lxc/cgroup.c
>>> +++ b/src/lxc/cgroup.c
>>> @@ -782,10 +782,8 @@ struct cgroup_process_info *lxc_cgroupfs_create(const char *name, const char *pa
>>>
>>>  		if (lxc_string_in_array("ns", (const char **)h->subsystems))
>>>  			continue;
>>> -		if (handle_cgroup_settings(mp, info_ptr->cgroup_path) < 0) {
>>> -			ERROR("Could not set clone_children to 1 for cpuset hierarchy in parent cgroup.");
>>> +		if (handle_cgroup_settings(mp, info_ptr->cgroup_path) < 0)
>>>  			goto out_initial_error;
>>> -		}
>>>  	}
>>>
>>>  	/* normalize the path */
>>> @@ -2016,43 +2014,60 @@ static int handle_cgroup_settings(struct cgroup_mount_point *mp,
>>>  {
>>>  	int r, saved_errno = 0;
>>>  	char buf[2];
>>> +	const char **subsystems = (const char **)mp->hierarchy->subsystems;
>>>
>>>  	/* If this is the memory cgroup, we want to enforce hierarchy.
>>>  	 * But don't fail if for some reason we can't.
>>>  	 */
>>> -	if (lxc_string_in_array("memory", (const char **)mp->hierarchy->subsystems)) {
>>> -		char *cc_path = cgroup_to_absolute_path(mp, cgroup_path, "/memory.use_hierarchy");
>>> -		if (cc_path) {
>>> -			r = lxc_read_from_file(cc_path, buf, 1);
>>> -			if (r < 1 || buf[0] != '1') {
>>> -				r = lxc_write_to_file(cc_path, "1", 1, false);
>>> -				if (r < 0)
>>> -					SYSERROR("failed to set memory.use_hiararchy to 1; continuing");
>>> -			}
>>> +	if (lxc_string_in_array("memory", subsystems)) {
>>> +		char *cc_path = cgroup_to_absolute_path(mp, cgroup_path,
>>> +						"/memory.use_hierarchy");
>>> +		if (!cc_path)
>>> +			goto cpuset;
>>> +
>>> +		r = lxc_read_from_file(cc_path, buf, 1);
>>> +		if (r == 1 && buf[0] == '1') {
>>>  			free(cc_path);
>>> +			goto cpuset;
>>>  		}
>>> +
>>> +		r = lxc_write_to_file(cc_path, "1", 1, false);
>>> +		if (r < 0)
>>> +			SYSERROR("Failed to set memory.use_hiararchy to 1; continuing");
>>> +		free(cc_path);
>>>  	}
>>>
>>>  	/* if this is a cpuset hierarchy, we have to set cgroup.clone_children in
>>>  	 * the base cgroup, otherwise containers will start with an empty cpuset.mems
>>>  	 * and cpuset.cpus and then
>>>  	 */
>>> -	if (lxc_string_in_array("cpuset", (const char **)mp->hierarchy->subsystems)) {
>>> -		char *cc_path = cgroup_to_absolute_path(mp, cgroup_path, "/cgroup.clone_children");
>>> +cpuset:
>>> +	if (lxc_string_in_array("cpuset", subsystems)) {
>>> +		char *cc_path = cgroup_to_absolute_path(mp, cgroup_path,
>>> +						"/cgroup.clone_children");
>>>  		if (!cc_path)
>>> -			return -1;
>>> +			goto err;
>>> +
>>>  		r = lxc_read_from_file(cc_path, buf, 1);
>>>  		if (r == 1 && buf[0] == '1') {
>>>  			free(cc_path);
>>> -			return 0;
>>> +			goto out;
>>>  		}
>>> +
>>>  		r = lxc_write_to_file(cc_path, "1", 1, false);
>>> -		saved_errno = errno;
>>> +		if (r < 0) {
>>> +			SYSERROR("Failed to set clone_children to 1 for cpuset hierarchy in parent cgroup.");
>>> +			saved_errno = errno;
>>> +			free(cc_path);
>>> +			errno = saved_errno;
>>> +			goto err;
>>> +		}
>>>  		free(cc_path);
>>> -		errno = saved_errno;
>>> -		return r < 0 ? -1 : 0;
>>>  	}
>>> +out:
>>>  	return 0;
>>> +err:
>>> +	return -1;
>>>  }
>>>
>>>  extern void lxc_monitor_send_state(const char *name, lxc_state_t state,
>>>
>>
>>
> 
> .
>