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allow for large KTR_ENTRIES values by allocating ktr_buf using malloc(9)

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Only during very early boot, before malloc(9) is functional (SI_SUB_KMEM),
the static ktr_buf_init is used.  Size of the static buffer is determined
by a new kernel option KTR_BOOT_ENTRIES.  Its default value is 1024.

This commit builds on top of r243046.

Reviewed by:	alc
MFC after:	17 days
This commit is contained in:
Andriy Gapon 2013-02-03 09:57:39 +00:00
parent bf861ada38
commit 36b7dde416
3 changed files with 33 additions and 3 deletions
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5
sys/conf/NOTES
View File

@ -446,6 +446,8 @@ options KTRACE_REQUEST_POOL=101
# KTR is a kernel tracing facility imported from BSD/OS. It is
# enabled with the KTR option. KTR_ENTRIES defines the number of
# entries in the circular trace buffer; it may be an arbitrary number.
# KTR_BOOT_ENTRIES defines the number of entries during the early boot,
# before malloc(9) is functional.
# KTR_COMPILE defines the mask of events to compile into the kernel as
# defined by the KTR_* constants in <sys/ktr.h>. KTR_MASK defines the
# initial value of the ktr_mask variable which determines at runtime
@ -459,7 +461,8 @@ options KTRACE_REQUEST_POOL=101
# if KTR_VERBOSE is not defined. See ktr(4) and ktrdump(8) for details.
#
options KTR
options KTR_ENTRIES=1024
options KTR_BOOT_ENTRIES=1024
options KTR_ENTRIES=(128 * 1024)
options KTR_COMPILE=(KTR_INTR|KTR_PROC)
options KTR_MASK=KTR_INTR
options KTR_CPUMASK=0x3

1
sys/conf/options
View File

@ -669,6 +669,7 @@ KTR_ALQ opt_ktr.h
KTR_MASK opt_ktr.h
KTR_CPUMASK opt_ktr.h
KTR_COMPILE opt_global.h
KTR_BOOT_ENTRIES opt_global.h
KTR_ENTRIES opt_global.h
KTR_VERBOSE opt_ktr.h
WITNESS opt_global.h

30
sys/kern/kern_ktr.c
View File

@ -66,6 +66,10 @@ __FBSDID("$FreeBSD$");
#include <ddb/db_output.h>
#endif
#ifndef KTR_BOOT_ENTRIES
#define KTR_BOOT_ENTRIES 1024
#endif
#ifndef KTR_ENTRIES
#define KTR_ENTRIES 1024
#endif
@ -96,9 +100,9 @@ FEATURE(ktr, "Kernel support for KTR kernel tracing facility");
volatile int ktr_idx = 0;
int ktr_mask = KTR_MASK;
int ktr_compile = KTR_COMPILE;
int ktr_entries = KTR_ENTRIES;
int ktr_entries = KTR_BOOT_ENTRIES;
int ktr_version = KTR_VERSION;
struct ktr_entry ktr_buf_init[KTR_ENTRIES];
struct ktr_entry ktr_buf_init[KTR_BOOT_ENTRIES];
struct ktr_entry *ktr_buf = ktr_buf_init;
cpuset_t ktr_cpumask = CPUSET_T_INITIALIZER(KTR_CPUMASK);
static char ktr_cpumask_str[CPUSETBUFSIZ];
@ -194,6 +198,28 @@ SYSCTL_PROC(_debug_ktr, OID_AUTO, mask, CTLTYPE_UINT|CTLFLAG_RW, 0, 0,
sysctl_debug_ktr_mask, "IU",
"Bitmask of KTR event classes for which logging is enabled");
#if KTR_ENTRIES != KTR_BOOT_ENTRIES
/*
* A simplified version of sysctl_debug_ktr_entries.
* No need to care about SMP, scheduling, etc.
*/
static void
ktr_entries_initializer(void *dummy __unused)
{
int mask;
/* Temporarily disable ktr in case malloc() is being traced. */
mask = ktr_mask;
ktr_mask = 0;
ktr_buf = malloc(sizeof(*ktr_buf) * KTR_ENTRIES, M_KTR,
M_WAITOK | M_ZERO);
ktr_entries = KTR_ENTRIES;
ktr_mask = mask;
}
SYSINIT(ktr_entries_initializer, SI_SUB_KMEM, SI_ORDER_ANY,
ktr_entries_initializer, NULL);
#endif
static int
sysctl_debug_ktr_entries(SYSCTL_HANDLER_ARGS)
{