svn commit: r249344 - head/lib/libkvm
Gleb Smirnoff
glebius at FreeBSD.org
Wed Apr 10 20:26:55 UTC 2013
Author: glebius
Date: Wed Apr 10 20:26:53 2013
New Revision: 249344
URL: http://svnweb.freebsd.org/changeset/base/249344
Log:
o Provide function kvm_read_zpcpu() to access UMA_ZONE_PCPU allocations.
o Provide function kvm_counter_u64_fetch() to fetch valut of a counter(9).
Sponsored by: Nginx, Inc.
Modified:
head/lib/libkvm/Makefile
head/lib/libkvm/kvm.h
head/lib/libkvm/kvm_getpcpu.3
head/lib/libkvm/kvm_pcpu.c
Modified: head/lib/libkvm/Makefile
==============================================================================
--- head/lib/libkvm/Makefile Wed Apr 10 18:59:20 2013 (r249343)
+++ head/lib/libkvm/Makefile Wed Apr 10 20:26:53 2013 (r249344)
@@ -25,8 +25,10 @@ MAN= kvm.3 kvm_getcptime.3 kvm_geterr.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
Modified: head/lib/libkvm/kvm.h
==============================================================================
--- head/lib/libkvm/kvm.h Wed Apr 10 18:59:20 2013 (r249343)
+++ head/lib/libkvm/kvm.h Wed Apr 10 20:26:53 2013 (r249344)
@@ -78,6 +78,7 @@ char *kvm_getfiles(kvm_t *, int, int, i
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);
Modified: head/lib/libkvm/kvm_getpcpu.3
==============================================================================
--- head/lib/libkvm/kvm_getpcpu.3 Wed Apr 10 18:59:20 2013 (r249343)
+++ head/lib/libkvm/kvm_getpcpu.3 Wed Apr 10 20:26:53 2013 (r249344)
@@ -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
Modified: head/lib/libkvm/kvm_pcpu.c
==============================================================================
--- head/lib/libkvm/kvm_pcpu.c Wed Apr 10 18:59:20 2013 (r249343)
+++ head/lib/libkvm/kvm_pcpu.c Wed Apr 10 20:26:53 2013 (r249344)
@@ -1,4 +1,5 @@
/*-
+ * Copyright (c) 2013 Gleb Smirnoff <glebius at FreeBSD.org>
* Copyright (c) 2010 Juniper Networks, Inc.
* Copyright (c) 2009 Robert N. M. Watson
* Copyright (c) 2009 Bjoern A. Zeeb <bz at 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);
+}
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