From a3b89864554bbce1594b7abdb5739fc708c1ca95 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 29 Apr 2020 17:05:15 +0200 Subject: [PATCH] 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) Signed-off-by: Ingo Molnar Acked-by: Tejun Heo Acked-by: Davidlohr Bueso --- 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 451c2d26a5db..4f2f79de083e 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 55d18791a72d..3d890961f6e5 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; } /* -- 2.39.5