Re: [PATCH v2 00/10] cgroup: Assign subsystem IDs during compile time

On 24.08.2012 16:01, Daniel Wagner wrote:

CGROUP_BUILTIN_SUBSYS_COUNT is also gone in this version.  This time I
trade space for speed. Some extra cycles are spend to identify the
modules in the for loops, e.g.

for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
	struct cgroup_subsys_state *ss = cgrp->subsys[i];

	/* at bootup time, we don't worry about modular subsystems */
	if (!ss || (ss && ss->module))
		continue;

	[...]
}

CGROUP_SUBSYS_COUNT is currently 12 if all controllers are built.  I
haven't found any other way to get rid of CGROUP_BUILTIN_SUBSYS_COUNT
without real dirty preprocessor tricks.

As usual, the good ideas come right after sending patches:

enum cgroup_subsys_id {
#define SUBSYS(_x) _x ## _subsys_id,

#define IS_SUBSYS_ENABLED(option) IS_BUILTIN(option)
#include <linux/cgroup_subsys.h>
#undef IS_SUBSYS_ENABLED

	CGROUP_BUILTIN_SUBSYS_COUNT,
	CGROUP_BUILTIN_SUBSYS_LAST = CGROUP_BUILTIN_SUBSYS_COUNT - 1,

#define IS_SUBSYS_ENABLED(option) IS_MODULE(option)
#include <linux/cgroup_subsys.h>
#undef IS_SUBSYS_ENABLED

#undef SUBSYS

	CGROUP_SUBSYS_COUNT,
};

Would that be an acceptable solution?

cheers,
daniel