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4469 DTrace helper tracing should be dynamic

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illumos/illumos-gate@902686d13f
This commit is contained in:
Mark Johnston 2014-06-03 01:52:05 +00:00
parent db9dbc75dd
commit ced1f492b7
1 changed files with 52 additions and 31 deletions
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83
uts/common/dtrace/dtrace.c
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@ -269,17 +269,22 @@ dtrace_id_t dtrace_probeid_error; /* special ERROR probe */
/*
* DTrace Helper Tracing Variables
*
* These variables should be set dynamically to enable helper tracing. The
* only variables that should be set are dtrace_helptrace_enable (which should
* be set to a non-zero value to allocate helper tracing buffers on the next
* open of /dev/dtrace) and dtrace_helptrace_disable (which should be set to a
* non-zero value to deallocate helper tracing buffers on the next close of
* /dev/dtrace). When (and only when) helper tracing is disabled, the
* buffer size may also be set via dtrace_helptrace_bufsize.
*/
uint32_t dtrace_helptrace_next = 0;
uint32_t dtrace_helptrace_nlocals;
char *dtrace_helptrace_buffer;
int dtrace_helptrace_bufsize = 512 * 1024;
#ifdef DEBUG
int dtrace_helptrace_enabled = 1;
#else
int dtrace_helptrace_enabled = 0;
#endif
int dtrace_helptrace_enable = 0;
int dtrace_helptrace_disable = 0;
int dtrace_helptrace_bufsize = 16 * 1024 * 1024;
uint32_t dtrace_helptrace_nlocals;
static dtrace_helptrace_t *dtrace_helptrace_buffer;
static uint32_t dtrace_helptrace_next = 0;
static int dtrace_helptrace_wrapped = 0;
/*
* DTrace Error Hashing
@ -14321,10 +14326,10 @@ dtrace_helper_trace(dtrace_helper_action_t *helper,
dtrace_mstate_t *mstate, dtrace_vstate_t *vstate, int where)
{
uint32_t size, next, nnext, i;
dtrace_helptrace_t *ent;
dtrace_helptrace_t *ent, *buffer;
uint16_t flags = cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
if (!dtrace_helptrace_enabled)
if ((buffer = dtrace_helptrace_buffer) == NULL)
return;
ASSERT(vstate->dtvs_nlocals <= dtrace_helptrace_nlocals);
@ -14352,10 +14357,12 @@ dtrace_helper_trace(dtrace_helper_action_t *helper,
/*
* We have our slot; fill it in.
*/
if (nnext == size)
if (nnext == size) {
dtrace_helptrace_wrapped++;
next = 0;
}
ent = (dtrace_helptrace_t *)&dtrace_helptrace_buffer[next];
ent = (dtrace_helptrace_t *)((uintptr_t)buffer + next);
ent->dtht_helper = helper;
ent->dtht_where = where;
ent->dtht_nlocals = vstate->dtvs_nlocals;
@ -14389,7 +14396,7 @@ dtrace_helper(int which, dtrace_mstate_t *mstate,
dtrace_helper_action_t *helper;
dtrace_vstate_t *vstate;
dtrace_difo_t *pred;
int i, trace = dtrace_helptrace_enabled;
int i, trace = dtrace_helptrace_buffer != NULL;
ASSERT(which >= 0 && which < DTRACE_NHELPER_ACTIONS);
@ -15705,17 +15712,6 @@ dtrace_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
dtrace_anon_property();
mutex_exit(&cpu_lock);
/*
* If DTrace helper tracing is enabled, we need to allocate the
* trace buffer and initialize the values.
*/
if (dtrace_helptrace_enabled) {
ASSERT(dtrace_helptrace_buffer == NULL);
dtrace_helptrace_buffer =
kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP);
dtrace_helptrace_next = 0;
}
/*
* If there are already providers, we must ask them to provide their
* probes, and then match any anonymous enabling against them. Note
@ -15812,6 +15808,18 @@ dtrace_open(dev_t *devp, int flag, int otyp, cred_t *cred_p)
return (EBUSY);
}
if (dtrace_helptrace_enable && dtrace_helptrace_buffer == NULL) {
/*
* If DTrace helper tracing is enabled, we need to allocate the
* trace buffer and initialize the values.
*/
dtrace_helptrace_buffer =
kmem_zalloc(dtrace_helptrace_bufsize, KM_SLEEP);
dtrace_helptrace_next = 0;
dtrace_helptrace_wrapped = 0;
dtrace_helptrace_enable = 0;
}
state = dtrace_state_create(devp, cred_p);
mutex_exit(&cpu_lock);
@ -15833,6 +15841,7 @@ dtrace_close(dev_t dev, int flag, int otyp, cred_t *cred_p)
{
minor_t minor = getminor(dev);
dtrace_state_t *state;
dtrace_helptrace_t *buf = NULL;
if (minor == DTRACEMNRN_HELPER)
return (0);
@ -15850,6 +15859,18 @@ dtrace_close(dev_t dev, int flag, int otyp, cred_t *cred_p)
dtrace_state_destroy(state->dts_anon);
}
if (dtrace_helptrace_disable) {
/*
* If we have been told to disable helper tracing, set the
* buffer to NULL before calling into dtrace_state_destroy();
* we take advantage of its dtrace_sync() to know that no
* CPU is in probe context with enabled helper tracing
* after it returns.
*/
buf = dtrace_helptrace_buffer;
dtrace_helptrace_buffer = NULL;
}
dtrace_state_destroy(state);
ASSERT(dtrace_opens > 0);
@ -15860,6 +15881,11 @@ dtrace_close(dev_t dev, int flag, int otyp, cred_t *cred_p)
if (--dtrace_opens == 0 && dtrace_anon.dta_enabling == NULL)
(void) kdi_dtrace_set(KDI_DTSET_DTRACE_DEACTIVATE);
if (buf != NULL) {
kmem_free(buf, dtrace_helptrace_bufsize);
dtrace_helptrace_disable = 0;
}
mutex_exit(&dtrace_lock);
mutex_exit(&cpu_lock);
@ -16753,11 +16779,6 @@ dtrace_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
mutex_exit(&cpu_lock);
if (dtrace_helptrace_enabled) {
kmem_free(dtrace_helptrace_buffer, dtrace_helptrace_bufsize);
dtrace_helptrace_buffer = NULL;
}
kmem_free(dtrace_probes, dtrace_nprobes * sizeof (dtrace_probe_t *));
dtrace_probes = NULL;
dtrace_nprobes = 0;