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o Provide function kvm_read_zpcpu() to access UMA_ZONE_PCPU allocations.

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o Provide function kvm_counter_u64_fetch() to fetch valut of a counter(9).

Sponsored by:	Nginx, Inc.
This commit is contained in:
Gleb Smirnoff 2013-04-10 20:26:53 +00:00
parent 0e2ca4e625
commit 2a2134043c
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=249344
4 changed files with 89 additions and 7 deletions
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6
lib/libkvm/Makefile
View file

@ -25,8 +25,10 @@ MAN= kvm.3 kvm_getcptime.3 kvm_geterr.3 kvm_getfiles.3 kvm_getloadavg.3 \
kvm_getpcpu.3 kvm_getprocs.3 kvm_getswapinfo.3 kvm_nlist.3 kvm_open.3 \
kvm_read.3
MLINKS+=kvm_getpcpu.3 kvm_getmaxcpu.3
MLINKS+=kvm_getpcpu.3 kvm_dpcpu_setcpu.3
MLINKS+=kvm_getpcpu.3 kvm_getmaxcpu.3 \
kvm_getpcpu.3 kvm_dpcpu_setcpu.3 \
kvm_getpcpu.3 kvm_read_zpcpu.3 \
kvm_getpcpu.3 kvm_counter_u64_fetch
MLINKS+=kvm_getprocs.3 kvm_getargv.3 kvm_getprocs.3 kvm_getenvv.3
MLINKS+=kvm_open.3 kvm_close.3 kvm_open.3 kvm_openfiles.3
MLINKS+=kvm_read.3 kvm_write.3

2
lib/libkvm/kvm.h
View file

@ -78,6 +78,7 @@ char *kvm_getfiles(kvm_t *, int, int, int *);
int kvm_getloadavg(kvm_t *, double [], int);
int kvm_getmaxcpu(kvm_t *);
void *kvm_getpcpu(kvm_t *, int);
uint64_t kvm_counter_u64_fetch(kvm_t *, u_long);
struct kinfo_proc *
kvm_getprocs(kvm_t *, int, int, int *);
int kvm_getswapinfo(kvm_t *, struct kvm_swap *, int, int);
@ -87,6 +88,7 @@ kvm_t *kvm_open
kvm_t *kvm_openfiles
(const char *, const char *, const char *, int, char *);
ssize_t kvm_read(kvm_t *, unsigned long, void *, size_t);
ssize_t kvm_read_zpcpu(kvm_t *, void *, u_long, size_t, int);
ssize_t kvm_uread
(kvm_t *, const struct kinfo_proc *, unsigned long, char *, size_t);
ssize_t kvm_write(kvm_t *, unsigned long, const void *, size_t);

37
lib/libkvm/kvm_getpcpu.3
View file

@ -28,7 +28,7 @@
.\"
.\" $FreeBSD$
.\"
.Dd February 28, 2010
.Dd April 11, 2013
.Dt KVM_GETPCPU 3
.Os
.Sh NAME
@ -49,6 +49,10 @@
.Fn kvm_getmaxcpu "kvm_t *kd"
.Ft void *
.Fn kvm_getpcpu "kvm_t *kd" "int cpu"
.Ft ssize_t
.Fn kvm_read_zpcpu "kvm_t *kd" "void *buf" "u_long base" "size_t size" "int cpu"
.Ft uint64_t
.Fn kvm_counter_u64_fetch "kvm_t *kd" "u_long base"
.Sh DESCRIPTION
The
.Fn kvm_dpcpu_setcpu ,
@ -83,6 +87,28 @@ is not active, then
.Dv NULL
is returned instead.
.Pp
The
.Fn kvm_read_zpcpu
function is used to obtain private per-CPU copy from a
.Dv UMA_ZONE_PCPU
.Xr zone 9 .
It takes
.Fa base
argument as base address of an allocation and copyies
.Fa size
bytes into
.Fa buf
from the part of allocation that is private to
.Fa cpu .
.Pp
The
.Fn kvm_counter_u64_fetch
function fetches value of a
.Xr counter 9
pointed by
.Fa base
address.
.Pp
Symbols for dynamic per-CPU data are accessed via
.Xr kvm_nlist 3
as with other symbols.
@ -122,9 +148,16 @@ On success, the
.Fn kvm_dpcpu_setcpu
call returns 0; if an error occurs, it returns -1 instead.
.Pp
On success, the
.Fn kvm_read_zpcpu
function returns number of bytes copied.
If an error occurs, it returns -1 instead.
.Pp
If any function encounters an error,
then an error message may be retrieved via
.Xr kvm_geterr 3 .
.Sh SEE ALSO
.Xr free 3 ,
.Xr kvm 3
.Xr kvm 3 ,
.Xr counter 9 ,
.Xr zone 9

51
lib/libkvm/kvm_pcpu.c
View file

@ -1,4 +1,5 @@
/*-
* Copyright (c) 2013 Gleb Smirnoff <glebius@FreeBSD.org>
* Copyright (c) 2010 Juniper Networks, Inc.
* Copyright (c) 2009 Robert N. M. Watson
* Copyright (c) 2009 Bjoern A. Zeeb <bz@FreeBSD.org>
@ -50,8 +51,12 @@ __FBSDID("$FreeBSD$");
static struct nlist kvm_pcpu_nl[] = {
{ .n_name = "_cpuid_to_pcpu" },
{ .n_name = "_mp_maxcpus" },
{ .n_name = "_mp_ncpus" },
{ .n_name = NULL },
};
#define NL_CPUID_TO_PCPU 0
#define NL_MP_MAXCPUS 1
#define NL_MP_NCPUS 2
/*
* Kernel per-CPU data state. We cache this stuff on the first
@ -63,9 +68,7 @@ static struct nlist kvm_pcpu_nl[] = {
*/
static void **pcpu_data;
static int maxcpu;
#define NL_CPUID_TO_PCPU 0
#define NL_MP_MAXCPUS 1
static int mp_ncpus;
static int
_kvm_pcpu_init(kvm_t *kd)
@ -89,6 +92,15 @@ _kvm_pcpu_init(kvm_t *kd)
_kvm_err(kd, kd->program, "cannot read mp_maxcpus");
return (-1);
}
if (kvm_pcpu_nl[NL_MP_NCPUS].n_value == 0) {
_kvm_err(kd, kd->program, "unable to find mp_ncpus");
return (-1);
}
if (kvm_read(kd, kvm_pcpu_nl[NL_MP_NCPUS].n_value, &mp_ncpus,
sizeof(mp_ncpus)) != sizeof(mp_ncpus)) {
_kvm_err(kd, kd->program, "cannot read mp_ncpus");
return (-1);
}
len = max * sizeof(void *);
data = malloc(len);
if (data == NULL) {
@ -289,3 +301,36 @@ kvm_dpcpu_setcpu(kvm_t *kd, u_int cpu)
return (_kvm_dpcpu_setcpu(kd, cpu, 1));
}
/*
* Obtain a per-CPU copy for given cpu from UMA_ZONE_PCPU allocation.
*/
ssize_t
kvm_read_zpcpu(kvm_t *kd, void *buf, u_long base, size_t size, int cpu)
{
return (kvm_read(kd, (uintptr_t)(base + sizeof(struct pcpu) * cpu),
buf, size));
}
/*
* Fetch value of a counter(9).
*/
uint64_t
kvm_counter_u64_fetch(kvm_t *kd, u_long base)
{
uint64_t r, c;
if (mp_ncpus == 0)
if (_kvm_pcpu_init(kd) < 0)
return (0);
r = 0;
for (int i = 0; i < mp_ncpus; i++) {
if (kvm_read_zpcpu(kd, &c, base, sizeof(c), i) != sizeof(c))
return (0);
r += c;
}
return (r);
}