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DEFINITIONS
This source file includes following definitions.
- ktrace_init
- ktrace_uninit
- ktrace_alloc
- ktrace_free
- ktrace_enter
- ktrace_nentries
- ktrace_first
- ktrace_next
- ktrace_skip
/*
* Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <xfs.h>
static kmem_zone_t *ktrace_hdr_zone;
static kmem_zone_t *ktrace_ent_zone;
static int ktrace_zentries;
void __init
ktrace_init(int zentries)
{
ktrace_zentries = roundup_pow_of_two(zentries);
ktrace_hdr_zone = kmem_zone_init(sizeof(ktrace_t),
"ktrace_hdr");
ASSERT(ktrace_hdr_zone);
ktrace_ent_zone = kmem_zone_init(ktrace_zentries
* sizeof(ktrace_entry_t),
"ktrace_ent");
ASSERT(ktrace_ent_zone);
}
void __exit
ktrace_uninit(void)
{
kmem_zone_destroy(ktrace_hdr_zone);
kmem_zone_destroy(ktrace_ent_zone);
}
/*
* ktrace_alloc()
*
* Allocate a ktrace header and enough buffering for the given
* number of entries. Round the number of entries up to a
* power of 2 so we can do fast masking to get the index from
* the atomic index counter.
*/
ktrace_t *
ktrace_alloc(int nentries, unsigned int __nocast sleep)
{
ktrace_t *ktp;
ktrace_entry_t *ktep;
int entries;
ktp = (ktrace_t*)kmem_zone_alloc(ktrace_hdr_zone, sleep);
if (ktp == (ktrace_t*)NULL) {
/*
* KM_SLEEP callers don't expect failure.
*/
if (sleep & KM_SLEEP)
panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
return NULL;
}
/*
* Special treatment for buffers with the ktrace_zentries entries
*/
entries = roundup_pow_of_two(nentries);
if (entries == ktrace_zentries) {
ktep = (ktrace_entry_t*)kmem_zone_zalloc(ktrace_ent_zone,
sleep);
} else {
ktep = (ktrace_entry_t*)kmem_zalloc((entries * sizeof(*ktep)),
sleep | KM_LARGE);
}
if (ktep == NULL) {
/*
* KM_SLEEP callers don't expect failure.
*/
if (sleep & KM_SLEEP)
panic("ktrace_alloc: NULL memory on KM_SLEEP request!");
kmem_free(ktp);
return NULL;
}
ktp->kt_entries = ktep;
ktp->kt_nentries = entries;
ASSERT(is_power_of_2(entries));
ktp->kt_index_mask = entries - 1;
atomic_set(&ktp->kt_index, 0);
ktp->kt_rollover = 0;
return ktp;
}
/*
* ktrace_free()
*
* Free up the ktrace header and buffer. It is up to the caller
* to ensure that no-one is referencing it.
*/
void
ktrace_free(ktrace_t *ktp)
{
int entries_size;
if (ktp == (ktrace_t *)NULL)
return;
/*
* Special treatment for the Vnode trace buffer.
*/
if (ktp->kt_nentries == ktrace_zentries) {
kmem_zone_free(ktrace_ent_zone, ktp->kt_entries);
} else {
entries_size = (int)(ktp->kt_nentries * sizeof(ktrace_entry_t));
kmem_free(ktp->kt_entries);
}
kmem_zone_free(ktrace_hdr_zone, ktp);
}
/*
* Enter the given values into the "next" entry in the trace buffer.
* kt_index is always the index of the next entry to be filled.
*/
void
ktrace_enter(
ktrace_t *ktp,
void *val0,
void *val1,
void *val2,
void *val3,
void *val4,
void *val5,
void *val6,
void *val7,
void *val8,
void *val9,
void *val10,
void *val11,
void *val12,
void *val13,
void *val14,
void *val15)
{
int index;
ktrace_entry_t *ktep;
ASSERT(ktp != NULL);
/*
* Grab an entry by pushing the index up to the next one.
*/
index = atomic_add_return(1, &ktp->kt_index);
index = (index - 1) & ktp->kt_index_mask;
if (!ktp->kt_rollover && index == ktp->kt_nentries - 1)
ktp->kt_rollover = 1;
ASSERT((index >= 0) && (index < ktp->kt_nentries));
ktep = &(ktp->kt_entries[index]);
ktep->val[0] = val0;
ktep->val[1] = val1;
ktep->val[2] = val2;
ktep->val[3] = val3;
ktep->val[4] = val4;
ktep->val[5] = val5;
ktep->val[6] = val6;
ktep->val[7] = val7;
ktep->val[8] = val8;
ktep->val[9] = val9;
ktep->val[10] = val10;
ktep->val[11] = val11;
ktep->val[12] = val12;
ktep->val[13] = val13;
ktep->val[14] = val14;
ktep->val[15] = val15;
}
/*
* Return the number of entries in the trace buffer.
*/
int
ktrace_nentries(
ktrace_t *ktp)
{
int index;
if (ktp == NULL)
return 0;
index = atomic_read(&ktp->kt_index) & ktp->kt_index_mask;
return (ktp->kt_rollover ? ktp->kt_nentries : index);
}
/*
* ktrace_first()
*
* This is used to find the start of the trace buffer.
* In conjunction with ktrace_next() it can be used to
* iterate through the entire trace buffer. This code does
* not do any locking because it is assumed that it is called
* from the debugger.
*
* The caller must pass in a pointer to a ktrace_snap
* structure in which we will keep some state used to
* iterate through the buffer. This state must not touched
* by any code outside of this module.
*/
ktrace_entry_t *
ktrace_first(ktrace_t *ktp, ktrace_snap_t *ktsp)
{
ktrace_entry_t *ktep;
int index;
int nentries;
if (ktp->kt_rollover)
index = atomic_read(&ktp->kt_index) & ktp->kt_index_mask;
else
index = 0;
ktsp->ks_start = index;
ktep = &(ktp->kt_entries[index]);
nentries = ktrace_nentries(ktp);
index++;
if (index < nentries) {
ktsp->ks_index = index;
} else {
ktsp->ks_index = 0;
if (index > nentries)
ktep = NULL;
}
return ktep;
}
/*
* ktrace_next()
*
* This is used to iterate through the entries of the given
* trace buffer. The caller must pass in the ktrace_snap_t
* structure initialized by ktrace_first(). The return value
* will be either a pointer to the next ktrace_entry or NULL
* if all of the entries have been traversed.
*/
ktrace_entry_t *
ktrace_next(
ktrace_t *ktp,
ktrace_snap_t *ktsp)
{
int index;
ktrace_entry_t *ktep;
index = ktsp->ks_index;
if (index == ktsp->ks_start) {
ktep = NULL;
} else {
ktep = &ktp->kt_entries[index];
}
index++;
if (index == ktrace_nentries(ktp)) {
ktsp->ks_index = 0;
} else {
ktsp->ks_index = index;
}
return ktep;
}
/*
* ktrace_skip()
*
* Skip the next "count" entries and return the entry after that.
* Return NULL if this causes us to iterate past the beginning again.
*/
ktrace_entry_t *
ktrace_skip(
ktrace_t *ktp,
int count,
ktrace_snap_t *ktsp)
{
int index;
int new_index;
ktrace_entry_t *ktep;
int nentries = ktrace_nentries(ktp);
index = ktsp->ks_index;
new_index = index + count;
while (new_index >= nentries) {
new_index -= nentries;
}
if (index == ktsp->ks_start) {
/*
* We've iterated around to the start, so we're done.
*/
ktep = NULL;
} else if ((new_index < index) && (index < ktsp->ks_index)) {
/*
* We've skipped past the start again, so we're done.
*/
ktep = NULL;
ktsp->ks_index = ktsp->ks_start;
} else {
ktep = &(ktp->kt_entries[new_index]);
new_index++;
if (new_index == nentries) {
ktsp->ks_index = 0;
} else {
ktsp->ks_index = new_index;
}
}
return ktep;
}