Commit a3b89864 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

rbtree, perf: Use new rbtree helpers 



Reduce rbtree boiler plate by using the new helpers.

One noteworthy change is unification of the various (partial) compare
functions. We construct a subtree match by forcing the sub-order to
always match, see __group_cmp().

Due to 'const' we had to touch cgroup_id().

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarDavidlohr Bueso <dbueso@suse.de>
parent 8ecca394

include/linux/cgroup.h

+2 −2
Original line number Diff line number Diff line
@@ -307,7 +307,7 @@ void css_task_iter_end(struct css_task_iter *it); 
 * Inline functions.

 */



static inline u64 cgroup_id(struct cgroup *cgrp)

static inline u64 cgroup_id(const struct cgroup *cgrp)

{

	return cgrp->kn->id;

}
@@ -701,7 +701,7 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen); 
struct cgroup_subsys_state;

struct cgroup;



static inline u64 cgroup_id(struct cgroup *cgrp) { return 1; }

static inline u64 cgroup_id(const struct cgroup *cgrp) { return 1; }

static inline void css_get(struct cgroup_subsys_state *css) {}

static inline void css_put(struct cgroup_subsys_state *css) {}

static inline int cgroup_attach_task_all(struct task_struct *from,

kernel/events/core.c

+90 −105
Original line number Diff line number Diff line
@@ -1595,50 +1595,91 @@ static void perf_event_groups_init(struct perf_event_groups *groups) 
	groups->index = 0;

}



static inline struct cgroup *event_cgroup(const struct perf_event *event)

{

	struct cgroup *cgroup = NULL;



#ifdef CONFIG_CGROUP_PERF

	if (event->cgrp)

		cgroup = event->cgrp->css.cgroup;

#endif



	return cgroup;

}



/*

 * Compare function for event groups;

 *

 * Implements complex key that first sorts by CPU and then by virtual index

 * which provides ordering when rotating groups for the same CPU.

 */

static bool

perf_event_groups_less(struct perf_event *left, struct perf_event *right)

static __always_inline int

perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,

		      const u64 left_group_index, const struct perf_event *right)

{

	if (left->cpu < right->cpu)

		return true;

	if (left->cpu > right->cpu)

		return false;

	if (left_cpu < right->cpu)

		return -1;

	if (left_cpu > right->cpu)

		return 1;



#ifdef CONFIG_CGROUP_PERF

	if (left->cgrp != right->cgrp) {

		if (!left->cgrp || !left->cgrp->css.cgroup) {

	{

		const struct cgroup *right_cgroup = event_cgroup(right);



		if (left_cgroup != right_cgroup) {

			if (!left_cgroup) {

				/*

			 * Left has no cgroup but right does, no cgroups come

			 * first.

				 * Left has no cgroup but right does, no

				 * cgroups come first.

				 */

			return true;

				return -1;

			}

		if (!right->cgrp || !right->cgrp->css.cgroup) {

			if (!right_cgroup) {

				/*

			 * Right has no cgroup but left does, no cgroups come

			 * first.

				 * Right has no cgroup but left does, no

				 * cgroups come first.

				 */

			return false;

				return 1;

			}

			/* Two dissimilar cgroups, order by id. */

		if (left->cgrp->css.cgroup->kn->id < right->cgrp->css.cgroup->kn->id)

			return true;

			if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))

				return -1;



		return false;

			return 1;

		}

	}

#endif



	if (left->group_index < right->group_index)

		return true;

	if (left->group_index > right->group_index)

		return false;

	if (left_group_index < right->group_index)

		return -1;

	if (left_group_index > right->group_index)

		return 1;



	return false;

	return 0;

}



#define __node_2_pe(node) \

	rb_entry((node), struct perf_event, group_node)



static inline bool __group_less(struct rb_node *a, const struct rb_node *b)

{

	struct perf_event *e = __node_2_pe(a);

	return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,

				     __node_2_pe(b)) < 0;

}



struct __group_key {

	int cpu;

	struct cgroup *cgroup;

};



static inline int __group_cmp(const void *key, const struct rb_node *node)

{

	const struct __group_key *a = key;

	const struct perf_event *b = __node_2_pe(node);



	/* partial/subtree match: @cpu, @cgroup; ignore: @group_index */

	return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);

}



/*
@@ -1650,27 +1691,9 @@ static void 
perf_event_groups_insert(struct perf_event_groups *groups,

			 struct perf_event *event)

{

	struct perf_event *node_event;

	struct rb_node *parent;

	struct rb_node **node;



	event->group_index = ++groups->index;



	node = &groups->tree.rb_node;

	parent = *node;



	while (*node) {

		parent = *node;

		node_event = container_of(*node, struct perf_event, group_node);



		if (perf_event_groups_less(event, node_event))

			node = &parent->rb_left;

		else

			node = &parent->rb_right;

	}



	rb_link_node(&event->group_node, parent, node);

	rb_insert_color(&event->group_node, &groups->tree);

	rb_add(&event->group_node, &groups->tree, __group_less);

}



/*
@@ -1718,45 +1741,17 @@ static struct perf_event * 
perf_event_groups_first(struct perf_event_groups *groups, int cpu,

			struct cgroup *cgrp)

{

	struct perf_event *node_event = NULL, *match = NULL;

	struct rb_node *node = groups->tree.rb_node;

#ifdef CONFIG_CGROUP_PERF

	u64 node_cgrp_id, cgrp_id = 0;



	if (cgrp)

		cgrp_id = cgrp->kn->id;

#endif



	while (node) {

		node_event = container_of(node, struct perf_event, group_node);



		if (cpu < node_event->cpu) {

			node = node->rb_left;

			continue;

		}

		if (cpu > node_event->cpu) {

			node = node->rb_right;

			continue;

		}

#ifdef CONFIG_CGROUP_PERF

		node_cgrp_id = 0;

		if (node_event->cgrp && node_event->cgrp->css.cgroup)

			node_cgrp_id = node_event->cgrp->css.cgroup->kn->id;

	struct __group_key key = {

		.cpu = cpu,

		.cgroup = cgrp,

	};

	struct rb_node *node;



		if (cgrp_id < node_cgrp_id) {

			node = node->rb_left;

			continue;

		}

		if (cgrp_id > node_cgrp_id) {

			node = node->rb_right;

			continue;

		}

#endif

		match = node_event;

		node = node->rb_left;

	}

	node = rb_find_first(&key, &groups->tree, __group_cmp);

	if (node)

		return __node_2_pe(node);



	return match;

	return NULL;

}



/*
@@ -1765,27 +1760,17 @@ perf_event_groups_first(struct perf_event_groups *groups, int cpu, 
static struct perf_event *

perf_event_groups_next(struct perf_event *event)

{

	struct perf_event *next;

#ifdef CONFIG_CGROUP_PERF

	u64 curr_cgrp_id = 0;

	u64 next_cgrp_id = 0;

#endif



	next = rb_entry_safe(rb_next(&event->group_node), typeof(*event), group_node);

	if (next == NULL || next->cpu != event->cpu)

		return NULL;



#ifdef CONFIG_CGROUP_PERF

	if (event->cgrp && event->cgrp->css.cgroup)

		curr_cgrp_id = event->cgrp->css.cgroup->kn->id;

	struct __group_key key = {

		.cpu = event->cpu,

		.cgroup = event_cgroup(event),

	};

	struct rb_node *next;



	if (next->cgrp && next->cgrp->css.cgroup)

		next_cgrp_id = next->cgrp->css.cgroup->kn->id;

	next = rb_next_match(&key, &event->group_node, __group_cmp);

	if (next)

		return __node_2_pe(next);



	if (curr_cgrp_id != next_cgrp_id)

	return NULL;

#endif

	return next;

}



/*