Add COUNTER_U64_SYSINIT() and COUNTER_U64_DEFINE_EARLY().

The aim is to reduce the boilerplate needed today to define and
initialize global counters.  Also add SI_SUB_COUNTER to the sysinit
ordering.

Reviewed by:	kib
MFC after:	1 week
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D23977

5 files changed, 52 insertions, 3 deletions

diff --git a/share/man/man9/counter.9 b/share/man/man9/counter.9
index 9bdb5320b71b..1eb36b571249 100644
--- a/share/man/man9/counter.9
+++ b/share/man/man9/counter.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 22, 2017
+.Dd March 6, 2020
 .Dt COUNTER 9
 .Os
 .Sh NAME
@@ -53,6 +53,8 @@
 .Fn counter_u64_zero "counter_u64_t c"
 .Ft int64_t
 .Fn counter_ratecheck "struct counter_rate *cr" "int64_t limit"
+.Fn COUNTER_U64_SYSINIT "counter_u64_t c"
+.Fn COUNTER_U64_DEFINE_EARLY "counter_u64_t c"
 .In sys/sysctl.h
 .Fn SYSCTL_COUNTER_U64 parent nbr name access ptr descr
 .Fn SYSCTL_ADD_COUNTER_U64 ctx parent nbr name access ptr descr
@@ -142,6 +144,20 @@ If the limit was reached on previous second, but was just reset back to zero,
 then
 .Fn counter_ratecheck
 returns number of events since previous reset.
+.It Fn COUNTER_U64_SYSINIT c
+Define a
+.Xr SYSINIT 9
+initializer for the global counter
+.Fa c .
+.It Fn COUNTER_U64_DEFINE_EARLY c
+Define and initialize a global counter
+.Fa c .
+It is always safe to increment
+.Fa c ,
+though updates prior to the
+.Dv SI_SUB_COUNTER
+.Xr SYSINIT 9
+event are lost.
 .It Fn SYSCTL_COUNTER_U64 parent nbr name access ptr descr
 Declare a static
 .Xr sysctl 9
@@ -245,6 +261,7 @@ SYSCTL_COUNTER_U64_ARRAY(_debug, OID_AUTO, counter_array, CTLFLAG_RW,
 .Xr malloc 9 ,
 .Xr ratecheck 9 ,
 .Xr sysctl 9 ,
+.Xr SYSINIT 9 ,
 .Xr uma 9
 .Sh HISTORY
 The
diff --git a/sys/kern/subr_counter.c b/sys/kern/subr_counter.c
index 8eb9f19e158c..fec51b6b635a 100644
--- a/sys/kern/subr_counter.c
+++ b/sys/kern/subr_counter.c
@@ -172,3 +172,21 @@ counter_ratecheck(struct counter_rate *cr, int64_t limit)
 
 	return (val);
 }
+
+void
+counter_u64_sysinit(void *arg)
+{
+	counter_u64_t *cp;
+
+	cp = arg;
+	*cp = counter_u64_alloc(M_WAITOK);
+}
+
+void
+counter_u64_sysuninit(void *arg)
+{
+	counter_u64_t *cp;
+
+	cp = arg;
+	counter_u64_free(*cp);
+}
diff --git a/sys/kern/subr_pcpu.c b/sys/kern/subr_pcpu.c
index 101440e3b1ec..f37b9324a919 100644
--- a/sys/kern/subr_pcpu.c
+++ b/sys/kern/subr_pcpu.c
@@ -148,7 +148,7 @@ pcpu_zones_startup(void)
 	pcpu_zone_64 = uma_zcreate("64 pcpu", sizeof(uint64_t),
 	    NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_PCPU);
 }
-SYSINIT(pcpu_zones, SI_SUB_VM, SI_ORDER_ANY, pcpu_zones_startup, NULL);
+SYSINIT(pcpu_zones, SI_SUB_COUNTER, SI_ORDER_FIRST, pcpu_zones_startup, NULL);
 
 /*
  * First-fit extent based allocator for allocating space in the per-cpu
diff --git a/sys/sys/counter.h b/sys/sys/counter.h
index 9960a2c39d8e..3e1b7828d5d4 100644
--- a/sys/sys/counter.h
+++ b/sys/sys/counter.h
@@ -74,5 +74,18 @@ struct counter_rate {
 
 int64_t	counter_ratecheck(struct counter_rate *, int64_t);
 
+#define	COUNTER_U64_SYSINIT(c)					\
+	SYSINIT(c##_counter_sysinit, SI_SUB_COUNTER,		\
+	    SI_ORDER_ANY, counter_u64_sysinit, &c);		\
+	SYSUNINIT(c##_counter_sysuninit, SI_SUB_COUNTER,	\
+	    SI_ORDER_ANY, counter_u64_sysuninit, &c)
+
+#define	COUNTER_U64_DEFINE_EARLY(c)				\
+	counter_u64_t __read_mostly c = EARLY_COUNTER;		\
+	COUNTER_U64_SYSINIT(c)
+
+void counter_u64_sysinit(void *);
+void counter_u64_sysuninit(void *);
+
 #endif	/* _KERNEL */
 #endif	/* ! __SYS_COUNTER_H__ */
diff --git a/sys/sys/kernel.h b/sys/sys/kernel.h
index 839f26706f47..3b0e038b5c83 100644
--- a/sys/sys/kernel.h
+++ b/sys/sys/kernel.h
@@ -91,7 +91,8 @@ enum sysinit_sub_id {
 	SI_SUB_DONE		= 0x0000001,	/* processed*/
 	SI_SUB_TUNABLES		= 0x0700000,	/* establish tunable values */
 	SI_SUB_COPYRIGHT	= 0x0800001,	/* first use of console*/
-	SI_SUB_VM		= 0x1000000,	/* virtual memory system init*/
+	SI_SUB_VM		= 0x1000000,	/* virtual memory system init */
+	SI_SUB_COUNTER		= 0x1100000,	/* counter(9) is initialized */
 	SI_SUB_KMEM		= 0x1800000,	/* kernel memory*/
 	SI_SUB_HYPERVISOR	= 0x1A40000,	/*
 						 * Hypervisor detection and