diff options
| -rw-r--r-- | include/linux/jump_label.h | 24 | ||||
| -rw-r--r-- | include/linux/perf_event.h | 6 | ||||
| -rw-r--r-- | kernel/events/core.c | 13 | ||||
| -rw-r--r-- | kernel/jump_label.c | 35 |
4 files changed, 68 insertions, 10 deletions
diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index 388b0d425b50..a1e7f909c801 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -3,6 +3,7 @@ #include <linux/types.h> #include <linux/compiler.h> +#include <linux/workqueue.h> #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) @@ -14,6 +15,12 @@ struct jump_label_key { #endif }; +struct jump_label_key_deferred { + struct jump_label_key key; + unsigned long timeout; + struct delayed_work work; +}; + # include <asm/jump_label.h> # define HAVE_JUMP_LABEL #endif /* CC_HAVE_ASM_GOTO && CONFIG_JUMP_LABEL */ @@ -51,8 +58,11 @@ extern void arch_jump_label_transform_static(struct jump_entry *entry, extern int jump_label_text_reserved(void *start, void *end); extern void jump_label_inc(struct jump_label_key *key); extern void jump_label_dec(struct jump_label_key *key); +extern void jump_label_dec_deferred(struct jump_label_key_deferred *key); extern bool jump_label_enabled(struct jump_label_key *key); extern void jump_label_apply_nops(struct module *mod); +extern void jump_label_rate_limit(struct jump_label_key_deferred *key, + unsigned long rl); #else /* !HAVE_JUMP_LABEL */ @@ -68,6 +78,10 @@ static __always_inline void jump_label_init(void) { } +struct jump_label_key_deferred { + struct jump_label_key key; +}; + static __always_inline bool static_branch(struct jump_label_key *key) { if (unlikely(atomic_read(&key->enabled))) @@ -85,6 +99,11 @@ static inline void jump_label_dec(struct jump_label_key *key) atomic_dec(&key->enabled); } +static inline void jump_label_dec_deferred(struct jump_label_key_deferred *key) +{ + jump_label_dec(&key->key); +} + static inline int jump_label_text_reserved(void *start, void *end) { return 0; @@ -102,6 +121,11 @@ static inline int jump_label_apply_nops(struct module *mod) { return 0; } + +static inline void jump_label_rate_limit(struct jump_label_key_deferred *key, + unsigned long rl) +{ +} #endif /* HAVE_JUMP_LABEL */ #endif /* _LINUX_JUMP_LABEL_H */ diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index cb44c9e75660..564769cdb473 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1064,12 +1064,12 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) } } -extern struct jump_label_key perf_sched_events; +extern struct jump_label_key_deferred perf_sched_events; static inline void perf_event_task_sched_in(struct task_struct *prev, struct task_struct *task) { - if (static_branch(&perf_sched_events)) + if (static_branch(&perf_sched_events.key)) __perf_event_task_sched_in(prev, task); } @@ -1078,7 +1078,7 @@ static inline void perf_event_task_sched_out(struct task_struct *prev, { perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, NULL, 0); - if (static_branch(&perf_sched_events)) + if (static_branch(&perf_sched_events.key)) __perf_event_task_sched_out(prev, next); } diff --git a/kernel/events/core.c b/kernel/events/core.c index 3c1541d7a53d..3a3b1a18f490 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -128,7 +128,7 @@ enum event_type_t { * perf_sched_events : >0 events exist * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu */ -struct jump_label_key perf_sched_events __read_mostly; +struct jump_label_key_deferred perf_sched_events __read_mostly; static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); static atomic_t nr_mmap_events __read_mostly; @@ -2748,7 +2748,7 @@ static void free_event(struct perf_event *event) if (!event->parent) { if (event->attach_state & PERF_ATTACH_TASK) - jump_label_dec(&perf_sched_events); + jump_label_dec_deferred(&perf_sched_events); if (event->attr.mmap || event->attr.mmap_data) atomic_dec(&nr_mmap_events); if (event->attr.comm) @@ -2759,7 +2759,7 @@ static void free_event(struct perf_event *event) put_callchain_buffers(); if (is_cgroup_event(event)) { atomic_dec(&per_cpu(perf_cgroup_events, event->cpu)); - jump_label_dec(&perf_sched_events); + jump_label_dec_deferred(&perf_sched_events); } } @@ -5784,7 +5784,7 @@ done: if (!event->parent) { if (event->attach_state & PERF_ATTACH_TASK) - jump_label_inc(&perf_sched_events); + jump_label_inc(&perf_sched_events.key); if (event->attr.mmap || event->attr.mmap_data) atomic_inc(&nr_mmap_events); if (event->attr.comm) @@ -6022,7 +6022,7 @@ SYSCALL_DEFINE5(perf_event_open, * - that may need work on context switch */ atomic_inc(&per_cpu(perf_cgroup_events, event->cpu)); - jump_label_inc(&perf_sched_events); + jump_label_inc(&perf_sched_events.key); } /* @@ -6868,6 +6868,9 @@ void __init perf_event_init(void) ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); + + /* do not patch jump label more than once per second */ + jump_label_rate_limit(&perf_sched_events, HZ); } static int __init perf_event_sysfs_init(void) diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 66ff7109f697..51a175ab0a03 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -72,15 +72,46 @@ void jump_label_inc(struct jump_label_key *key) jump_label_unlock(); } -void jump_label_dec(struct jump_label_key *key) +static void __jump_label_dec(struct jump_label_key *key, + unsigned long rate_limit, struct delayed_work *work) { if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) return; - jump_label_update(key, JUMP_LABEL_DISABLE); + if (rate_limit) { + atomic_inc(&key->enabled); + schedule_delayed_work(work, rate_limit); + } else + jump_label_update(key, JUMP_LABEL_DISABLE); + jump_label_unlock(); } +static void jump_label_update_timeout(struct work_struct *work) +{ + struct jump_label_key_deferred *key = + container_of(work, struct jump_label_key_deferred, work.work); + __jump_label_dec(&key->key, 0, NULL); +} + +void jump_label_dec(struct jump_label_key *key) +{ + __jump_label_dec(key, 0, NULL); +} + +void jump_label_dec_deferred(struct jump_label_key_deferred *key) +{ + __jump_label_dec(&key->key, key->timeout, &key->work); +} + + +void jump_label_rate_limit(struct jump_label_key_deferred *key, + unsigned long rl) +{ + key->timeout = rl; + INIT_DELAYED_WORK(&key->work, jump_label_update_timeout); +} + static int addr_conflict(struct jump_entry *entry, void *start, void *end) { if (entry->code <= (unsigned long)end && |