On Fri, 18 Nov 2011 17:39:03 -0200
Glauber Costa [off-list ref] wrote:

On 11/17/2011 07:35 PM, David Miller wrote:

quoted

TCP specific stuff in mm/memcontrol.c, at best that's not nice at all.

How crucial is that? Thing is that as far as I am concerned, all the 
memcg people really want the inner layout of struct mem_cgroup to be 
private to memcontrol.c 

This is just because memcg is just related to memory management and I don't
want it be wide spreaded, 'struct mem_cgroup' has been changed often.

But I don't like to have TCP code in memcgroup.c.

New idea is welcome.

This means that at some point, we need to have
at least a wrapper in memcontrol.c that is able to calculate the offset
of the tcp structure, and since most functions are actually quite 
simple, that would just make us do more function calls.

Well, an alternative to that would be to use a void pointer in the newly 
added struct cg_proto to an already parsed memcg-related field
(in this case tcp_memcontrol), that would be passed to the functions
instead of the whole memcg structure. Do you think this would be 
preferable ?

like this ?

struct mem_cgroup_sub_controls {
	struct mem_cgroup *mem;
	union {
		struct tcp_mem_control tcp;
	} data;
};
/* for loosely coupled controls for memcg */
struct memcg_sub_controls_function
{
	struct memcg_sub_controls	(*create)(struct mem_cgroup *);
	struct memcg_sub_controls	(*destroy)(struct mem_cgroup *);
}

int register_memcg_sub_controls(char *name, 
		struct memcg_sub_controls_function *abis);


struct mem_cgroup {
	.....
	.....
	/* Root memcg will have no sub_controls! */
	struct memcg_sub_controls	*sub_controls[NR_MEMCG_SUB_CONTROLS];
}


Maybe some functions should be exported. 

Thanks,
-Kame


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