CFS CGroup: Code cleanup

Clean up some CFS CGroup code

- replace "cont" with "cgrp" in a few places in the CFS cgroup code, - use write_uint rather than write for cpu.shares write function

---
kernel/sched.c | 51 +++++++++++++++++----------------------------------

1 file changed, 17 insertions(+), 34 deletions(-)

Index: container-2.6.23-mm1/kernel/sched.c
===================================================================
@@ -6936,25 +6936,25 @@ unsigned long sched_group_shares(struct #ifdef CONFIG_FAIR_CGROUP_SCHED
 

/* return corresponding task_group object of a cgroup */ -static inline struct task_group *cgroup_tg(struct cgroup *cont) +static inline struct task_group *cgroup_tg(struct cgroup *cgrp) {
- return container_of(cgroup_subsys_state(cont, cpu_cgroup_subsys_id),
- struct task_group, css);
+ return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
+ struct task_group, css);
}

static struct cgroup_subsys_state * -cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) +cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)

{
	struct task_group *tg;

- if (!cont->parent) {

+	if (!cgrp->parent) {
		/* This is early initialization for the top cgroup */
-		init_task_group.css.cgroup = cont;
+		init_task_group.css.cgroup = cgrp;
		return &init_task_group.css;
	}

	/* we support only 1-level deep hierarchical scheduler atm */
-	if (cont->parent->parent)
+	if (cgrp->parent->parent)
		return ERR_PTR(-EINVAL);

	tg = sched_create_group();
@@ -6962,21 +6962,21 @@ cpu_cgroup_create(struct cgroup_subsys *
		return ERR_PTR(-ENOMEM);

	/* Bind the cgroup to task_group object we just created */

- tg->css.cgroup = cont;
+ tg->css.cgroup = cgrp;

	return &tg->css;
}

static void cpu_cgroup_destroy(struct cgroup_subsys *ss,
- struct cgroup *cont)
+ struct cgroup *cgrp)
{
- struct task_group *tg = cgroup_tg(cont);
+ struct task_group *tg = cgroup_tg(cgrp);

	sched_destroy_group(tg);
}

static int cpu_cgroup_can_attach(struct cgroup_subsys *ss,
- struct cgroup *cont, struct task_struct *tsk)
+ struct cgroup *cgrp, struct task_struct *tsk)

{
	/* We don't support RT-tasks being in separate groups */
	if (tsk->sched_class != &fair_sched_class)

@@ -6986,38 +6986,21 @@ static int cpu_cgroup_can_attach(struct }

static void
-cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cont, +cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cont, struct task_struct *tsk)

{
	sched_move_task(tsk);
}

-static ssize_t cpu_shares_write(struct cgroup *cont, struct cftype *cftype,
- struct file *file, const char __user *userbuf,
- size_t nbytes, loff_t *ppos)
+static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype,
+ u64 shareval)
{
- unsigned long shareval;
- struct task_group *tg = cgroup_tg(cont);
- char buffer[2*sizeof(unsigned long) + 1];
- int rc;
-
- if (nbytes > 2*sizeof(unsigned long)) /* safety check */
- return -E2BIG;
-
- if (copy_from_user(buffer, userbuf, nbytes))
- return -EFAULT;
-
- buffer[nbytes] = 0; /* nul-terminate */
- shareval = simple_strtoul(buffer, NULL, 10);
-
- rc = sched_group_set_shares(tg, shareval);
-
- return (rc < 0 ? rc : nbytes);
+ return sched_group_set_shares(cgroup_tg(cgrp), shareval);
}

-static u64 cpu_shares_read_uint(struct cgroup *cont, struct cftype *cft) +static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft) {
- struct task_group *tg = cgroup_tg(cont);
+ struct task_group *tg = cgroup_tg(cgrp);

	return (u64) tg->shares;
}

This change looks good to me. Thanks for doing it.

Minor nit: From pov of making this patch series git bisect safe, shouldn't we be registering a write_uint() handler in this patch as well?

Regards,
vatsa

Yes, we should. Sigh. I originally had the cleanup and the new reporting interface in the same patch, and decided to split them apart into a cleanup patch and a new feature patch, but clearly goofed. I'll resend tomorrow with the write_uint registration in the right place.

Paul

Yes, we should. Sigh. I originally had the cleanup and the new reporting interface in the same patch, and decided to split them apart into a cleanup patch and a new feature patch, but clearly goofed. I'll resend tomorrow with the write_uint registration in the right place.

Paul

OK, this wasn't a patch goof - the original patch in my tree does have the addition of write_uint in the cftype definition. I guess the last hunk got lost as I transferred it to the email.

Paul

OK, this wasn't a patch goof - the original patch in my tree does have the addition of write_uint in the cftype definition. I guess the last hunk got lost as I transferred it to the email.

Paul

This change looks good to me. Thanks for doing it.

Minor nit: From pov of making this patch series git bisect safe, shouldn't we be registering a write_uint() handler in this patch as well?

Regards,
vatsa