static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]()

So here's a boot tested patch on top of Jason's series that does
all the cleanups I talked about and turns jump labels into a
more intuitive to use facility. It should also address the
various misconceptions and confusions that surround jump labels.

Typical usage scenarios:

        #include <linux/static_key.h>

        struct static_key key = STATIC_KEY_INIT_TRUE;

        if (static_key_false(&key))
                do unlikely code
        else
                do likely code

Or:

        if (static_key_true(&key))
                do likely code
        else
                do unlikely code

The static key is modified via:

        static_key_slow_inc(&key);
        ...
        static_key_slow_dec(&key);

The 'slow' prefix makes it abundantly clear that this is an
expensive operation.

I've updated all in-kernel code to use this everywhere. Note
that I (intentionally) have not pushed through the rename
blindly through to the lowest levels: the actual jump-label
patching arch facility should be named like that, so we want to
decouple jump labels from the static-key facility a bit.

On non-jump-label enabled architectures static keys default to
likely()/unlikely() branches.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jason Baron <jbaron@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: a.p.zijlstra@chello.nl
Cc: mathieu.desnoyers@efficios.com
Cc: davem@davemloft.net
Cc: ddaney.cavm@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20120222085809.GA26397@elte.hu
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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
-         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.
+         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.
 
-	 On i386, options added to the compiler flags may increase
-	 the size of the kernel slightly.
+	 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 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

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)

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)

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"

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"

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"

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"

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"

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)
 {

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(&paravirt_steal_enabled);
+		static_key_slow_inc(&paravirt_steal_enabled);
 		if (steal_acc)
-			jump_label_inc(&paravirt_steal_rq_enabled);
+			static_key_slow_inc(&paravirt_steal_rq_enabled);
 	}
 
 	return 0;

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)
 {

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;
 }
 

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 __always_inline bool static_branch(struct jump_label_key *key)
+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_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)))
+	if (unlikely(atomic_read(&key->enabled)) > 0)
 		return true;
 	return false;
 }
 
-static inline void jump_label_inc(struct jump_label_key *key)
+static __always_inline bool static_key_true(struct static_key *key)
+{
+	if (likely(atomic_read(&key->enabled)) > 0)
+		return true;
+	return false;
+}
+
+/* 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 */

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;

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]);
 }

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);
 }
 

include/linux/static_key.h

@@ -0,0 +1 @@
+#include <linux/jump_label.h>

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;

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,

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);
 	}
 
 	/*