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Commit 8277434e authored by Paul Turner's avatar Paul Turner Committed by Ingo Molnar
Browse files

sched: Allow for positional tg_tree walks 



Extend walk_tg_tree to accept a positional argument

static int walk_tg_tree_from(struct task_group *from,
			     tg_visitor down, tg_visitor up, void *data)

Existing semantics are preserved, caller must hold rcu_lock() or sufficient
analogue.

Signed-off-by: default avatarPaul Turner <pjt@google.com>
Reviewed-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110721184757.677889157@google.com


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 671fd9da

kernel/sched.c

+37 −13
Original line number Diff line number Diff line
@@ -1591,20 +1591,23 @@ static inline void dec_cpu_load(struct rq *rq, unsigned long load) 
typedef int (*tg_visitor)(struct task_group *, void *);



/*

 * Iterate the full tree, calling @down when first entering a node and @up when

 * leaving it for the final time.

 * Iterate task_group tree rooted at *from, calling @down when first entering a

 * node and @up when leaving it for the final time.

 *

 * Caller must hold rcu_lock or sufficient equivalent.

 */

static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)

static int walk_tg_tree_from(struct task_group *from,

			     tg_visitor down, tg_visitor up, void *data)

{

	struct task_group *parent, *child;

	int ret;



	rcu_read_lock();

	parent = &root_task_group;

	parent = from;



down:

	ret = (*down)(parent, data);

	if (ret)

		goto out_unlock;

		goto out;

	list_for_each_entry_rcu(child, &parent->children, siblings) {

		parent = child;

		goto down;
@@ -1613,19 +1616,29 @@ static int walk_tg_tree(tg_visitor down, tg_visitor up, void *data) 
		continue;

	}

	ret = (*up)(parent, data);

	if (ret)

		goto out_unlock;

	if (ret || parent == from)

		goto out;



	child = parent;

	parent = parent->parent;

	if (parent)

		goto up;

out_unlock:

	rcu_read_unlock();



out:

	return ret;

}



/*

 * Iterate the full tree, calling @down when first entering a node and @up when

 * leaving it for the final time.

 *

 * Caller must hold rcu_lock or sufficient equivalent.

 */



static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)

{

	return walk_tg_tree_from(&root_task_group, down, up, data);

}



static int tg_nop(struct task_group *tg, void *data)

{

	return 0;
@@ -8870,13 +8883,19 @@ static int tg_rt_schedulable(struct task_group *tg, void *data) 


static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)

{

	int ret;



	struct rt_schedulable_data data = {

		.tg = tg,

		.rt_period = period,

		.rt_runtime = runtime,

	};



	return walk_tg_tree(tg_rt_schedulable, tg_nop, &data);

	rcu_read_lock();

	ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);

	rcu_read_unlock();



	return ret;

}



static int tg_set_rt_bandwidth(struct task_group *tg,
@@ -9333,6 +9352,7 @@ static int tg_cfs_schedulable_down(struct task_group *tg, void *data) 


static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota)

{

	int ret;

	struct cfs_schedulable_data data = {

		.tg = tg,

		.period = period,
@@ -9344,7 +9364,11 @@ static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) 
		do_div(data.quota, NSEC_PER_USEC);

	}



	return walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);

	rcu_read_lock();

	ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data);

	rcu_read_unlock();



	return ret;

}

#endif /* CONFIG_CFS_BANDWIDTH */

#endif /* CONFIG_FAIR_GROUP_SCHED */