diff options
31 files changed, 298 insertions, 205 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index 4f55c736be1..5b448a74d0f 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -47,18 +47,29 @@ config KPROBES If in doubt, say "N". config JUMP_LABEL - bool "Optimize trace point call sites" + bool "Optimize very unlikely/likely branches" depends on HAVE_ARCH_JUMP_LABEL help + This option enables a transparent branch optimization that + makes certain almost-always-true or almost-always-false branch + conditions even cheaper to execute within the kernel. + + Certain performance-sensitive kernel code, such as trace points, + scheduler functionality, networking code and KVM have such + branches and include support for this optimization technique. + If it is detected that the compiler has support for "asm goto", - the kernel will compile trace point locations with just a - nop instruction. When trace points are enabled, the nop will - be converted to a jump to the trace function. This technique - lowers overhead and stress on the branch prediction of the - processor. - - On i386, options added to the compiler flags may increase - the size of the kernel slightly. + the kernel will compile such branches with just a nop + instruction. When the condition flag is toggled to true, the + nop will be converted to a jump instruction to execute the + conditional block of instructions. + + This technique lowers overhead and stress on the branch prediction + of the processor and generally makes the kernel faster. The update + of the condition is slower, but those are always very rare. + + ( On 32-bit x86, the necessary options added to the compiler + flags may increase the size of the kernel slightly. ) config OPTPROBES def_bool y diff --git a/arch/ia64/include/asm/paravirt.h b/arch/ia64/include/asm/paravirt.h index 32551d304cd..b149b88ea79 100644 --- a/arch/ia64/include/asm/paravirt.h +++ b/arch/ia64/include/asm/paravirt.h @@ -281,9 +281,9 @@ paravirt_init_missing_ticks_accounting(int cpu) pv_time_ops.init_missing_ticks_accounting(cpu); } -struct jump_label_key; -extern struct jump_label_key paravirt_steal_enabled; -extern struct jump_label_key paravirt_steal_rq_enabled; +struct static_key; +extern struct static_key paravirt_steal_enabled; +extern struct static_key paravirt_steal_rq_enabled; static inline int paravirt_do_steal_accounting(unsigned long *new_itm) diff --git a/arch/ia64/kernel/paravirt.c b/arch/ia64/kernel/paravirt.c index 100868216c5..1b22f6de293 100644 --- a/arch/ia64/kernel/paravirt.c +++ b/arch/ia64/kernel/paravirt.c @@ -634,8 +634,8 @@ struct pv_irq_ops pv_irq_ops = { * pv_time_ops * time operations */ -struct jump_label_key paravirt_steal_enabled; -struct jump_label_key paravirt_steal_rq_enabled; +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; static int ia64_native_do_steal_accounting(unsigned long *new_itm) diff --git a/arch/mips/include/asm/jump_label.h b/arch/mips/include/asm/jump_label.h index 1881b316ca4..4d6d77ed9b9 100644 --- a/arch/mips/include/asm/jump_label.h +++ b/arch/mips/include/asm/jump_label.h @@ -20,7 +20,7 @@ #define WORD_INSN ".word" #endif -static __always_inline bool arch_static_branch(struct jump_label_key *key) +static __always_inline bool arch_static_branch(struct static_key *key) { asm goto("1:\tnop\n\t" "nop\n\t" diff --git a/arch/powerpc/include/asm/jump_label.h b/arch/powerpc/include/asm/jump_label.h index 938986e412f..ae098c438f0 100644 --- a/arch/powerpc/include/asm/jump_label.h +++ b/arch/powerpc/include/asm/jump_label.h @@ -17,7 +17,7 @@ #define JUMP_ENTRY_TYPE stringify_in_c(FTR_ENTRY_LONG) #define JUMP_LABEL_NOP_SIZE 4 -static __always_inline bool arch_static_branch(struct jump_label_key *key) +static __always_inline bool arch_static_branch(struct static_key *key) { asm goto("1:\n\t" "nop\n\t" diff --git a/arch/s390/include/asm/jump_label.h b/arch/s390/include/asm/jump_label.h index 95a6cf2b5b6..6c32190dc73 100644 --- a/arch/s390/include/asm/jump_label.h +++ b/arch/s390/include/asm/jump_label.h @@ -13,7 +13,7 @@ #define ASM_ALIGN ".balign 4" #endif -static __always_inline bool arch_static_branch(struct jump_label_key *key) +static __always_inline bool arch_static_branch(struct static_key *key) { asm goto("0: brcl 0,0\n" ".pushsection __jump_table, \"aw\"\n" diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h index fc73a82366f..5080d16a832 100644 --- a/arch/sparc/include/asm/jump_label.h +++ b/arch/sparc/include/asm/jump_label.h @@ -7,7 +7,7 @@ #define JUMP_LABEL_NOP_SIZE 4 -static __always_inline bool arch_static_branch(struct jump_label_key *key) +static __always_inline bool arch_static_branch(struct static_key *key) { asm goto("1:\n\t" "nop\n\t" diff --git a/arch/x86/include/asm/jump_label.h b/arch/x86/include/asm/jump_label.h index a32b18ce6ea..3a16c1483b4 100644 --- a/arch/x86/include/asm/jump_label.h +++ b/arch/x86/include/asm/jump_label.h @@ -9,12 +9,12 @@ #define JUMP_LABEL_NOP_SIZE 5 -#define JUMP_LABEL_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t" +#define STATIC_KEY_INITIAL_NOP ".byte 0xe9 \n\t .long 0\n\t" -static __always_inline bool arch_static_branch(struct jump_label_key *key) +static __always_inline bool arch_static_branch(struct static_key *key) { asm goto("1:" - JUMP_LABEL_INITIAL_NOP + STATIC_KEY_INITIAL_NOP ".pushsection __jump_table, \"aw\" \n\t" _ASM_ALIGN "\n\t" _ASM_PTR "1b, %l[l_yes], %c0 \n\t" diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index a7d2db9a74f..c0180fd372d 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -230,9 +230,9 @@ static inline unsigned long long paravirt_sched_clock(void) return PVOP_CALL0(unsigned long long, pv_time_ops.sched_clock); } -struct jump_label_key; -extern struct jump_label_key paravirt_steal_enabled; -extern struct jump_label_key paravirt_steal_rq_enabled; +struct static_key; +extern struct static_key paravirt_steal_enabled; +extern struct static_key paravirt_steal_rq_enabled; static inline u64 paravirt_steal_clock(int cpu) { diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index f0c6fd6f176..694d801bf60 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -438,9 +438,9 @@ void __init kvm_guest_init(void) static __init int activate_jump_labels(void) { if (has_steal_clock) { - jump_label_inc(¶virt_steal_enabled); + static_key_slow_inc(¶virt_steal_enabled); if (steal_acc) - jump_label_inc(¶virt_steal_rq_enabled); + static_key_slow_inc(¶virt_steal_rq_enabled); } return 0; diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index d90272e6bc4..ada2f99388d 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -202,8 +202,8 @@ static void native_flush_tlb_single(unsigned long addr) __native_flush_tlb_single(addr); } -struct jump_label_key paravirt_steal_enabled; -struct jump_label_key paravirt_steal_rq_enabled; +struct static_key paravirt_steal_enabled; +struct static_key paravirt_steal_rq_enabled; static u64 native_steal_clock(int cpu) { diff --git a/arch/x86/kvm/mmu_audit.c b/arch/x86/kvm/mmu_audit.c index fe15dcc07a6..ea7b4fd3467 100644 --- a/arch/x86/kvm/mmu_audit.c +++ b/arch/x86/kvm/mmu_audit.c @@ -234,7 +234,7 @@ static void audit_vcpu_spte(struct kvm_vcpu *vcpu) } static bool mmu_audit; -static struct jump_label_key mmu_audit_key; +static struct static_key mmu_audit_key; static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { @@ -250,7 +250,7 @@ static void __kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) static inline void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { - if (static_branch((&mmu_audit_key))) + if (static_key_false((&mmu_audit_key))) __kvm_mmu_audit(vcpu, point); } @@ -259,7 +259,7 @@ static void mmu_audit_enable(void) if (mmu_audit) return; - jump_label_inc(&mmu_audit_key); + static_key_slow_inc(&mmu_audit_key); mmu_audit = true; } @@ -268,7 +268,7 @@ static void mmu_audit_disable(void) if (!mmu_audit) return; - jump_label_dec(&mmu_audit_key); + static_key_slow_dec(&mmu_audit_key); mmu_audit = false; } diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index f7c69580fea..2172da2d9bb 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -9,15 +9,15 @@ * * Jump labels provide an interface to generate dynamic branches using * self-modifying code. Assuming toolchain and architecture support the result - * of a "if (static_branch(&key))" statement is a unconditional branch (which + * of a "if (static_key_false(&key))" statement is a unconditional branch (which * defaults to false - and the true block is placed out of line). * - * However at runtime we can change the 'static' branch target using - * jump_label_{inc,dec}(). These function as a 'reference' count on the key + * However at runtime we can change the branch target using + * static_key_slow_{inc,dec}(). These function as a 'reference' count on the key * object and for as long as there are references all branches referring to * that particular key will point to the (out of line) true block. * - * Since this relies on modifying code the jump_label_{inc,dec}() functions + * Since this relies on modifying code the static_key_slow_{inc,dec}() functions * must be considered absolute slow paths (machine wide synchronization etc.). * OTOH, since the affected branches are unconditional their runtime overhead * will be absolutely minimal, esp. in the default (off) case where the total @@ -26,12 +26,26 @@ * * When the control is directly exposed to userspace it is prudent to delay the * decrement to avoid high frequency code modifications which can (and do) - * cause significant performance degradation. Struct jump_label_key_deferred and - * jump_label_dec_deferred() provide for this. + * cause significant performance degradation. Struct static_key_deferred and + * static_key_slow_dec_deferred() provide for this. * * Lacking toolchain and or architecture support, it falls back to a simple * conditional branch. - */ + * + * struct static_key my_key = STATIC_KEY_INIT_TRUE; + * + * if (static_key_true(&my_key)) { + * } + * + * will result in the true case being in-line and starts the key with a single + * reference. Mixing static_key_true() and static_key_false() on the same key is not + * allowed. + * + * Not initializing the key (static data is initialized to 0s anyway) is the + * same as using STATIC_KEY_INIT_FALSE and static_key_false() is + * equivalent with static_branch(). + * +*/ #include <linux/types.h> #include <linux/compiler.h> @@ -39,16 +53,17 @@ #if defined(CC_HAVE_ASM_GOTO) && defined(CONFIG_JUMP_LABEL) -struct jump_label_key { +struct static_key { atomic_t enabled; +/* Set lsb bit to 1 if branch is default true, 0 ot */ struct jump_entry *entries; #ifdef CONFIG_MODULES - struct jump_label_mod *next; + struct static_key_mod *next; #endif }; -struct jump_label_key_deferred { - struct jump_label_key key; +struct static_key_deferred { + struct static_key key; unsigned long timeout; struct delayed_work work; }; @@ -66,13 +81,34 @@ struct module; #ifdef HAVE_JUMP_LABEL -#ifdef CONFIG_MODULES -#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL, NULL} -#else -#define JUMP_LABEL_INIT {ATOMIC_INIT(0), NULL} -#endif +#define JUMP_LABEL_TRUE_BRANCH 1UL + +static +inline struct jump_entry *jump_label_get_entries(struct static_key *key) +{ + return (struct jump_entry *)((unsigned long)key->entries + & ~JUMP_LABEL_TRUE_BRANCH); +} + +static inline bool jump_label_get_branch_default(struct static_key *key) +{ + if ((unsigned long)key->entries & JUMP_LABEL_TRUE_BRANCH) + return true; + return false; +} + +static __always_inline bool static_key_false(struct static_key *key) +{ + return arch_static_branch(key); +} -static __always_inline bool static_branch(struct jump_label_key *key) +static __always_inline bool static_key_true(struct static_key *key) +{ + return !static_key_false(key); +} + +/* Deprecated. Please use 'static_key_false() instead. */ +static __always_inline bool static_branch(struct static_key *key) { return arch_static_branch(key); } @@ -88,21 +124,24 @@ extern void arch_jump_label_transform(struct jump_entry *entry, extern void arch_jump_label_transform_static(struct jump_entry *entry, enum jump_label_type type); 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 static_key_slow_inc(struct static_key *key); +extern void static_key_slow_dec(struct static_key *key); +extern void static_key_slow_dec_deferred(struct static_key_deferred *key); +extern bool static_key_enabled(struct static_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); +extern void +jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl); + +#define STATIC_KEY_INIT_TRUE ((struct static_key) \ + { .enabled = ATOMIC_INIT(1), .entries = (void *)1 }) +#define STATIC_KEY_INIT_FALSE ((struct static_key) \ + { .enabled = ATOMIC_INIT(0), .entries = (void *)0 }) #else /* !HAVE_JUMP_LABEL */ #include <linux/atomic.h> -#define JUMP_LABEL_INIT {ATOMIC_INIT(0)} - -struct jump_label_key { +struct static_key { atomic_t enabled; }; @@ -110,30 +149,45 @@ static __always_inline void jump_label_init(void) { } -struct jump_label_key_deferred { - struct jump_label_key key; +struct static_key_deferred { + struct static_key key; }; -static __always_inline bool static_branch(struct jump_label_key *key) +static __always_inline bool static_key_false(struct static_key *key) +{ + if (unlikely(atomic_read(&key->enabled)) > 0) + return true; + return false; +} + +static __always_inline bool static_key_true(struct static_key *key) { - if (unlikely(atomic_read(&key->enabled))) + if (likely(atomic_read(&key->enabled)) > 0) return true; return false; } -static inline void jump_label_inc(struct jump_label_key *key) +/* Deprecated. Please use 'static_key_false() instead. */ +static __always_inline bool static_branch(struct static_key *key) +{ + if (unlikely(atomic_read(&key->enabled)) > 0) + return true; + return false; +} + +static inline void static_key_slow_inc(struct static_key *key) { atomic_inc(&key->enabled); } -static inline void jump_label_dec(struct jump_label_key *key) +static inline void static_key_slow_dec(struct static_key *key) { atomic_dec(&key->enabled); } -static inline void jump_label_dec_deferred(struct jump_label_key_deferred *key) +static inline void static_key_slow_dec_deferred(struct static_key_deferred *key) { - jump_label_dec(&key->key); + static_key_slow_dec(&key->key); } static inline int jump_label_text_reserved(void *start, void *end) @@ -144,9 +198,9 @@ static inline int jump_label_text_reserved(void *start, void *end) static inline void jump_label_lock(void) {} static inline void jump_label_unlock(void) {} -static inline bool jump_label_enabled(struct jump_label_key *key) +static inline bool static_key_enabled(struct static_key *key) { - return !!atomic_read(&key->enabled); + return (atomic_read(&key->enabled) > 0); } static inline int jump_label_apply_nops(struct module *mod) @@ -154,13 +208,20 @@ 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, +static inline void +jump_label_rate_limit(struct static_key_deferred *key, unsigned long rl) { } + +#define STATIC_KEY_INIT_TRUE ((struct static_key) \ + { .enabled = ATOMIC_INIT(1) }) +#define STATIC_KEY_INIT_FALSE ((struct static_key) \ + { .enabled = ATOMIC_INIT(0) }) + #endif /* HAVE_JUMP_LABEL */ -#define jump_label_key_enabled ((struct jump_label_key){ .enabled = ATOMIC_INIT(1), }) -#define jump_label_key_disabled ((struct jump_label_key){ .enabled = ATOMIC_INIT(0), }) +#define STATIC_KEY_INIT STATIC_KEY_INIT_FALSE +#define jump_label_enabled static_key_enabled #endif /* _LINUX_JUMP_LABEL_H */ diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 0eac07c9525..7dfaae7846a 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -214,8 +214,8 @@ enum { #include <linux/skbuff.h> #ifdef CONFIG_RPS -#include <linux/jump_label.h> -extern struct jump_label_key rps_needed; +#include <linux/static_key.h> +extern struct static_key rps_needed; #endif struct neighbour; diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index b809265607d..29734be334c 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -163,13 +163,13 @@ extern struct ctl_path nf_net_ipv4_netfilter_sysctl_path[]; extern struct list_head nf_hooks[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; #if defined(CONFIG_JUMP_LABEL) -#include <linux/jump_label.h> -extern struct jump_label_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; +#include <linux/static_key.h> +extern struct static_key nf_hooks_needed[NFPROTO_NUMPROTO][NF_MAX_HOOKS]; static inline bool nf_hooks_active(u_int8_t pf, unsigned int hook) { if (__builtin_constant_p(pf) && __builtin_constant_p(hook)) - return static_branch(&nf_hooks_needed[pf][hook]); + return static_key_false(&nf_hooks_needed[pf][hook]); return !list_empty(&nf_hooks[pf][hook]); } diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 412b790f5da..0d21e6f1cf5 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -514,7 +514,7 @@ struct perf_guest_info_callbacks { #include <linux/ftrace.h> #include <linux/cpu.h> #include <linux/irq_work.h> -#include <linux/jump_label.h> +#include <linux/static_key.h> #include <linux/atomic.h> #include <asm/local.h> @@ -1038,7 +1038,7 @@ static inline int is_software_event(struct perf_event *event) return event->pmu->task_ctx_nr == perf_sw_context; } -extern struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; +extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; extern void __perf_sw_event(u32, u64, struct pt_regs *, u64); @@ -1066,7 +1066,7 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) { struct pt_regs hot_regs; - if (static_branch(&perf_swevent_enabled[event_id])) { + if (static_key_false(&perf_swevent_enabled[event_id])) { if (!regs) { perf_fetch_caller_regs(&hot_regs); regs = &hot_regs; @@ -1075,12 +1075,12 @@ perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr) } } -extern struct jump_label_key_deferred perf_sched_events; +extern struct static_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.key)) + if (static_key_false(&perf_sched_events.key)) __perf_event_task_sched_in(prev, task); } @@ -1089,7 +1089,7 @@ 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.key)) + if (static_key_false(&perf_sched_events.key)) __perf_event_task_sched_out(prev, next); } diff --git a/include/linux/static_key.h b/include/linux/static_key.h new file mode 100644 index 00000000000..27bd3f8a085 --- /dev/null +++ b/include/linux/static_key.h @@ -0,0 +1 @@ +#include <linux/jump_label.h> diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index fc36da97ff7..bd96ecd0e05 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -17,7 +17,7 @@ #include <linux/errno.h> #include <linux/types.h> #include <linux/rcupdate.h> -#include <linux/jump_label.h> +#include <linux/static_key.h> struct module; struct tracepoint; @@ -29,7 +29,7 @@ struct tracepoint_func { struct tracepoint { const char *name; /* Tracepoint name */ - struct jump_label_key key; + struct static_key key; void (*regfunc)(void); void (*unregfunc)(void); struct tracepoint_func __rcu *funcs; @@ -145,7 +145,7 @@ static inline void tracepoint_synchronize_unregister(void) extern struct tracepoint __tracepoint_##name; \ static inline void trace_##name(proto) \ { \ - if (static_branch(&__tracepoint_##name.key)) \ + if (static_key_false(&__tracepoint_##name.key)) \ __DO_TRACE(&__tracepoint_##name, \ TP_PROTO(data_proto), \ TP_ARGS(data_args), \ @@ -188,7 +188,7 @@ static inline void tracepoint_synchronize_unregister(void) __attribute__((section("__tracepoints_strings"))) = #name; \ struct tracepoint __tracepoint_##name \ __attribute__((section("__tracepoints"))) = \ - { __tpstrtab_##name, JUMP_LABEL_INIT, reg, unreg, NULL };\ + { __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\ static struct tracepoint * const __tracepoint_ptr_##name __used \ __attribute__((section("__tracepoints_ptrs"))) = \ &__tracepoint_##name; diff --git a/include/net/sock.h b/include/net/sock.h index 91c1c8baf02..dcde2d9268c 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -55,7 +55,7 @@ #include <linux/uaccess.h> #include <linux/memcontrol.h> #include <linux/res_counter.h> -#include <linux/jump_label.h> +#include <linux/static_key.h> #include <linux/filter.h> #include <linux/rculist_nulls.h> @@ -924,13 +924,13 @@ inline void sk_refcnt_debug_release(const struct sock *sk) #endif /* SOCK_REFCNT_DEBUG */ #if defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM) && defined(CONFIG_NET) -extern struct jump_label_key memcg_socket_limit_enabled; +extern struct static_key memcg_socket_limit_enabled; static inline struct cg_proto *parent_cg_proto(struct proto *proto, struct cg_proto *cg_proto) { return proto->proto_cgroup(parent_mem_cgroup(cg_proto->memcg)); } -#define mem_cgroup_sockets_enabled static_branch(&memcg_socket_limit_enabled) +#define mem_cgroup_sockets_enabled static_key_false(&memcg_socket_limit_enabled) #else #define mem_cgroup_sockets_enabled 0 static inline struct cg_proto *parent_cg_proto(struct proto *proto, diff --git a/kernel/events/core.c b/kernel/events/core.c index 7c3b9de55f6..5e0f8bb89b2 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_deferred perf_sched_events __read_mostly; +struct static_key_deferred perf_sched_events __read_mostly; static DEFINE_PER_CPU(atomic_t, perf_cgroup_events); static atomic_t nr_mmap_events __read_mostly; @@ -2769,7 +2769,7 @@ static void free_event(struct perf_event *event) if (!event->parent) { if (event->attach_state & PERF_ATTACH_TASK) - jump_label_dec_deferred(&perf_sched_events); + static_key_slow_dec_deferred(&perf_sched_events); if (event->attr.mmap || event->attr.mmap_data) atomic_dec(&nr_mmap_events); if (event->attr.comm) @@ -2780,7 +2780,7 @@ 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_deferred(&perf_sched_events); + static_key_slow_dec_deferred(&perf_sched_events); } } @@ -4982,7 +4982,7 @@ fail: return err; } -struct jump_label_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; +struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX]; static void sw_perf_event_destroy(struct perf_event *event) { @@ -4990,7 +4990,7 @@ static void sw_perf_event_destroy(struct perf_event *event) WARN_ON(event->parent); - jump_label_dec(&perf_swevent_enabled[event_id]); + static_key_slow_dec(&perf_swevent_enabled[event_id]); swevent_hlist_put(event); } @@ -5020,7 +5020,7 @@ static int perf_swevent_init(struct perf_event *event) if (err) return err; - jump_label_inc(&perf_swevent_enabled[event_id]); + static_key_slow_inc(&perf_swevent_enabled[event_id]); event->destroy = sw_perf_event_destroy; } @@ -5843,7 +5843,7 @@ done: if (!event->parent) { if (event->attach_state & PERF_ATTACH_TASK) - jump_label_inc(&perf_sched_events.key); + static_key_slow_inc(&perf_sched_events.key); if (event->attr.mmap || event->attr.mmap_data) atomic_inc(&nr_mmap_events); if (event->attr.comm) @@ -6081,7 +6081,7 @@ 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.key); + static_key_slow_inc(&perf_sched_events.key); } /* diff --git a/kernel/jump_label.c b/kernel/jump_label.c index 543782e7cdd..bf9dcadbb53 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -12,7 +12,7 @@ #include <linux/slab.h> #include <linux/sort.h> #include <linux/err.h> -#include <linux/jump_label.h> +#include <linux/static_key.h> #ifdef HAVE_JUMP_LABEL @@ -29,10 +29,11 @@ void jump_label_unlock(void) mutex_unlock(&jump_label_mutex); } -bool jump_label_enabled(struct jump_label_key *key) +bool static_key_enabled(struct static_key *key) { - return !!atomic_read(&key->enabled); + return (atomic_read(&key->enabled) > 0); } +EXPORT_SYMBOL_GPL(static_key_enabled); static int jump_label_cmp(const void *a, const void *b) { @@ -58,22 +59,26 @@ jump_label_sort_entries(struct jump_entry *start, struct jump_entry *stop) sort(start, size, sizeof(struct jump_entry), jump_label_cmp, NULL); } -static void jump_label_update(struct jump_label_key *key, int enable); +static void jump_label_update(struct static_key *key, int enable); -void jump_label_inc(struct jump_label_key *key) +void static_key_slow_inc(struct static_key *key) { if (atomic_inc_not_zero(&key->enabled)) return; jump_label_lock(); - if (atomic_read(&key->enabled) == 0) - jump_label_update(key, JUMP_LABEL_ENABLE); + if (atomic_read(&key->enabled) == 0) { + if (!jump_label_get_branch_default(key)) + jump_label_update(key, JUMP_LABEL_ENABLE); + else + jump_label_update(key, JUMP_LABEL_DISABLE); + } atomic_inc(&key->enabled); jump_label_unlock(); } -EXPORT_SYMBOL_GPL(jump_label_inc); +EXPORT_SYMBOL_GPL(static_key_slow_inc); -static void __jump_label_dec(struct jump_label_key *key, +static void __static_key_slow_dec(struct static_key *key, unsigned long rate_limit, struct delayed_work *work) { if (!atomic_dec_and_mutex_lock(&key->enabled, &jump_label_mutex)) { @@ -85,32 +90,35 @@ static void __jump_label_dec(struct jump_label_key *key, if (rate_limit) { atomic_inc(&key->enabled); schedule_delayed_work(work, rate_limit); - } else - jump_label_update(key, JUMP_LABEL_DISABLE); - |