On Fri, 2006-08-04 at 17:52 -0700, Joel Becker wrote:
<snip>
> > Here is how RG/CKRM uses configfs:
> >
> > - A Resource group is a group of tasks that uses specified amount of
> > resources.
> > - A Resource group is represented by a directory in configfs filesystem.
> > - Each directory has few attributes
> > - shares, list the amount of resource that group is allowed (rw)
> > - stats, usage statistics of the group (ro)
> > - members, list of tasks that are member of this group (rw)
>
> You could use 'mkdir' under members to create an object for each
> member:
>
> # mkdir config/ckrm/groups/thisresourcegroup/members/2209
>
> but I don't know how heavy or light that would be for you. I think
> someone in the previous mail chain thought this wasn't optimal.
tasks enter and exit a task group under following scenarios
- at fork (inherited from parent)
- at exit
- when user space explicitly moves a task from a group to another
Of these three only the last one is user initiated, and other two are
internal.
Also, it will be semantically wrong as the tasks are neither an item not
an attribute of an item. Resource group is an item and members is an
attribute.
>
> > The problem we have with is the members file, whose content could exceed
> > PAGE_SIZE when more than ~1000 tasks are in a group.
>
> Right, this I do understand.
>
> > We choose configfs instead of sysfs after following the guidance in the
> > doc.
> >
> > Basically we wanted a "file-system based manager of kernel object"
> > rather than a "file-system based view of a kernel object".
>
> Yes, I think configfs fits your intent well. I want to work
> together to see what we can do.
>
> > I think we could implement in sysfs also. But, doesn't sysfs also have
> > the PAGE_SIZE limitation.
>
> They do for standard attributes. That's where my limit comes
> from...I cut and pasted the code. However, sysfs also allows you to
> arbitrarily add objects to the filesystem tree, so you can place a
> seq_file or other object in the directory. The problem is that this
> object has an uncontrolled set of lifetime semantics. This has led to
> issues in the past. It's something I'm trying to avoid with configfs.
Our need does _not_ translate to a need for a new object. So, you don't
have to worry about uncontrolled feature creep :)
All we need is to make the PAGE_SIZE limit go away, and use the
attribute files as a seq_file.
>
> Joel
>
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Chandra Seetharaman | Be careful what you choose....
- [EMAIL PROTECTED] | .......you may get it.
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