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Date: Wed, 17 Feb 2021 13:17:37 -0000
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>, Tejun Heo <tj@...nel.org>,
Davidlohr Bueso <dbueso@...e.de>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: sched/core] rbtree, perf: Use new rbtree helpers
The following commit has been merged into the sched/core branch of tip:
Commit-ID: a3b89864554bbce1594b7abdb5739fc708c1ca95
Gitweb: https://git.kernel.org/tip/a3b89864554bbce1594b7abdb5739fc708c1ca95
Author: Peter Zijlstra <peterz@...radead.org>
AuthorDate: Wed, 29 Apr 2020 17:05:15 +02:00
Committer: Ingo Molnar <mingo@...nel.org>
CommitterDate: Wed, 17 Feb 2021 14:07:48 +01:00
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: Peter Zijlstra (Intel) <peterz@...radead.org>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Acked-by: Tejun Heo <tj@...nel.org>
Acked-by: Davidlohr Bueso <dbueso@...e.de>
---
include/linux/cgroup.h | 4 +-
kernel/events/core.c | 195 ++++++++++++++++++----------------------
2 files changed, 92 insertions(+), 107 deletions(-)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 451c2d2..4f2f79d 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -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,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 55d1879..3d89096 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -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) {
- /*
- * Left has no cgroup but right does, no cgroups come
- * first.
- */
- return true;
- }
- if (!right->cgrp || !right->cgrp->css.cgroup) {
- /*
- * Right has no cgroup but left does, no cgroups come
- * first.
- */
- return false;
- }
- /* Two dissimilar cgroups, order by id. */
- if (left->cgrp->css.cgroup->kn->id < right->cgrp->css.cgroup->kn->id)
- return true;
+ {
+ const struct cgroup *right_cgroup = event_cgroup(right);
- return false;
+ if (left_cgroup != right_cgroup) {
+ if (!left_cgroup) {
+ /*
+ * Left has no cgroup but right does, no
+ * cgroups come first.
+ */
+ return -1;
+ }
+ if (!right_cgroup) {
+ /*
+ * Right has no cgroup but left does, no
+ * cgroups come first.
+ */
+ return 1;
+ }
+ /* Two dissimilar cgroups, order by id. */
+ if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
+ return -1;
+
+ 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;
+ return NULL;
}
/*
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