Re: [RFC][PATCH][1/4] RSS controller setup

[Balbir Singh <balbir@in.ibm.com>]

Paul Menage wrote:
> On 2/19/07, Andrew Morton <akpm@linux-foundation.org> wrote:
>>
>> This output is hard to parse and to extend.  I'd suggest either two
>> separate files, or multi-line output:
>>
>> usage: %lu kB
>> limit: %lu kB
> 
> Two separate files would be the container usage model that I
> envisaged, inherited from the way cpusets does things.
> 
> And in this case, it should definitely be the limit in one file,
> readable and writeable, and the usage in another, probably only
> readable.
> 
> Having to read a file called memctlr_usage to find the current limit
> sounds wrong.
> 

That sound right, I'll fix this.

> Hmm, I don't appear to have documented this yet, but I think a good
> naming scheme for container files is <subsystem>.<whatever> - i.e.
> these should be memctlr.usage and memctlr.limit. The existing
> grandfathered Cpusets names violate this, but I'm not sure there's a
> lot we can do about that.
> 

Why <subsystem>.<whatever>, dots are harder to parse using regular
expressions and sound DOS'ish. I'd prefer "_" to separate the
subsystem and whatever :-)

>> > +static int memctlr_populate(struct container_subsys *ss,
>> > +                             struct container *cont)
>> > +{
>> > +     int rc;
>> > +     if ((rc = container_add_file(cont, &memctlr_usage)) < 0)
>> > +             return rc;
>> > +     if ((rc = container_add_file(cont, &memctlr_limit)) < 0)
>>
>> Clean up the first file here?
> 
> Containers don't currently provide an API for a subsystem to clean up
> files from a directory - that's done automatically when the directory
> is deleted.
> 
> I think I'll probably change the API for container_add_file to return
> void, but mark an error in the container itself if something goes
> wrong - that way rather than all the subsystems having to check for
> error, container_populate_dir() can do so at the end of calling all
> the subsystems' populate methods.
> 

It should be easy to add container_remove_file() instead of marking
an error.

> Paul


-- 
	Warm Regards,
	Balbir Singh