Re: [RFC][PATCH 4/7] UBC: syscalls (user interface)

[Kirill Korotaev <dev@sw.ru>]

>>Add the following system calls for UB management:
>>  1. sys_getluid    - get current UB id
>>  2. sys_setluid    - changes exec_ and fork_ UBs on current
>>  3. sys_setublimit - set limits for resources consumtions
>>
> 
> 
> Why not have another system call for getting the current limits?
will add sys_getublimit().

> But as I said in previous mail, configfs seems like a better choice for
> user interface.  That way user has to go to one place to read/write
> limits, see the current usage and other stats.
Check another email about interfaces. I have arguments against it :/

>>Signed-Off-By: Pavel Emelianov <xemul@sw.ru>
>>Signed-Off-By: Kirill Korotaev <dev@sw.ru>
> 
> 
> 	...<snip>...
> 
>>+
>>+/*
>>+ *	The setbeanlimit syscall
>>+ */
>>+asmlinkage long sys_setublimit(uid_t uid, unsigned long resource,
>>+		unsigned long *limits)
>>+{
> 
> 
>>+	ub = beancounter_findcreate(uid, NULL, 0);
>>+	if (ub == NULL)
>>+		goto out;
>>+
>>+	spin_lock_irqsave(&ub->ub_lock, flags);
>>+	ub->ub_parms[resource].barrier = new_limits[0];
>>+	ub->ub_parms[resource].limit = new_limits[1];
>>+	spin_unlock_irqrestore(&ub->ub_lock, flags);
>>+
> 
> 
> I think there should be a check here for seeing if the new limits are
> lower than the current usage of a resource.  If so then take appropriate
> action.
any idea what exact action to add here?
Looks like can be added when needed, agree?

Thanks,
Kirill