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hwpmc: Refactor sample ring buffer handling to fix races

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Refactor sample ring buffer ring handling to make it more robust to
long running callchain collection handling

r338112 introduced a (now fixed) regression that exposed a number of race
conditions within the management of the sample buffers. This
simplifies the handling and moves the decision to overwrite a
callchain sample that has taken too long out of the NMI in to the
hardlock handler. With this change the problem no longer shows up as a
ring corruption but as the code spending all of its time in callchain
collection.

- Makes the producer / consumer index incrementing monotonic, making it
  easier (for me at least) to reason about.
- Moves the decision to overwrite a sample from NMI context to interrupt
  context where we can enforce serialization.
- Puts a time limit on waiting to collect a user callchain - putting a
  bound on head-of-line blocking causing samples to be dropped
- Removes the flush routine which was previously needed to purge
  dangling references to the pmc from the sample buffers but now is only
  a source of a race condition on unload.

Previously one could lock up or crash HEAD by running:
pmcstat -S inst_retired.any_p -T and then hitting ^C

After this change it is no longer possible.

PR:	231793
Reviewed by:	markj@
Approved by:	re (gjb@)
Differential Revision:	https://reviews.freebsd.org/D17011
This commit is contained in:
Matt Macy 2018-10-05 05:55:56 +00:00
parent e8bb589d56
commit d9f1b8dbf2
4 changed files with 127 additions and 136 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
sys/dev/hwpmc/hwpmc_logging.c
View File

@ -234,7 +234,7 @@ static void pmclog_loop(void *arg);
static void pmclog_release(struct pmc_owner *po);
static uint32_t *pmclog_reserve(struct pmc_owner *po, int length);
static void pmclog_schedule_io(struct pmc_owner *po, int wakeup);
static void pmclog_schedule_all(struct pmc_owner *po, int force);
static void pmclog_schedule_all(struct pmc_owner *po);
static void pmclog_stop_kthread(struct pmc_owner *po);
/*
@ -842,7 +842,7 @@ pmclog_flush(struct pmc_owner *po, int force)
goto error;
}
pmclog_schedule_all(po, force);
pmclog_schedule_all(po);
error:
mtx_unlock(&pmc_kthread_mtx);
@ -850,7 +850,7 @@ pmclog_flush(struct pmc_owner *po, int force)
}
static void
pmclog_schedule_one_cond(struct pmc_owner *po, int force)
pmclog_schedule_one_cond(struct pmc_owner *po)
{
struct pmclog_buffer *plb;
int cpu;
@ -860,8 +860,7 @@ pmclog_schedule_one_cond(struct pmc_owner *po, int force)
/* tell hardclock not to run again */
if (PMC_CPU_HAS_SAMPLES(cpu))
PMC_CALL_HOOK_UNLOCKED(curthread, PMC_FN_DO_SAMPLES, NULL);
if (force)
pmc_flush_samples(cpu);
plb = po->po_curbuf[cpu];
if (plb && plb->plb_ptr != plb->plb_base)
pmclog_schedule_io(po, 1);
@ -869,7 +868,7 @@ pmclog_schedule_one_cond(struct pmc_owner *po, int force)
}
static void
pmclog_schedule_all(struct pmc_owner *po, int force)
pmclog_schedule_all(struct pmc_owner *po)
{
/*
* Schedule the current buffer if any and not empty.
@ -878,7 +877,7 @@ pmclog_schedule_all(struct pmc_owner *po, int force)
thread_lock(curthread);
sched_bind(curthread, i);
thread_unlock(curthread);
pmclog_schedule_one_cond(po, force);
pmclog_schedule_one_cond(po);
}
thread_lock(curthread);
sched_unbind(curthread);
@ -905,7 +904,7 @@ pmclog_close(struct pmc_owner *po)
/*
* Schedule the current buffer.
*/
pmclog_schedule_all(po, 0);
pmclog_schedule_all(po);
wakeup_one(po);
mtx_unlock(&pmc_kthread_mtx);

220
sys/dev/hwpmc/hwpmc_mod.c
View File

@ -211,7 +211,7 @@ static int pmc_debugflags_parse(char *newstr, char *fence);
#endif
static int load(struct module *module, int cmd, void *arg);
static int pmc_add_sample(int ring, struct pmc *pm, struct trapframe *tf);
static int pmc_add_sample(ring_type_t ring, struct pmc *pm, struct trapframe *tf);
static void pmc_add_thread_descriptors_from_proc(struct proc *p,
struct pmc_process *pp);
static int pmc_attach_process(struct proc *p, struct pmc *pm);
@ -249,7 +249,7 @@ static void pmc_process_csw_out(struct thread *td);
static void pmc_process_exit(void *arg, struct proc *p);
static void pmc_process_fork(void *arg, struct proc *p1,
struct proc *p2, int n);
static void pmc_process_samples(int cpu, int soft);
static void pmc_process_samples(int cpu, ring_type_t soft);
static void pmc_release_pmc_descriptor(struct pmc *pmc);
static void pmc_process_thread_add(struct thread *td);
static void pmc_process_thread_delete(struct thread *td);
@ -342,6 +342,7 @@ static int pmc_nsamples = PMC_NSAMPLES;
SYSCTL_INT(_kern_hwpmc, OID_AUTO, nsamples, CTLFLAG_RDTUN,
&pmc_nsamples, 0, "number of PC samples per CPU");
static uint64_t pmc_sample_mask = PMC_NSAMPLES-1;
/*
* kern.hwpmc.mtxpoolsize -- number of mutexes in the mutex pool.
@ -1402,6 +1403,10 @@ pmc_process_csw_in(struct thread *td)
if (pm->pm_state != PMC_STATE_RUNNING)
continue;
KASSERT(counter_u64_fetch(pm->pm_runcount) >= 0,
("[pmc,%d] pm=%p runcount %ld", __LINE__, (void *) pm,
(unsigned long)counter_u64_fetch(pm->pm_runcount)));
/* increment PMC runcount */
counter_u64_add(pm->pm_runcount, 1);
@ -1596,6 +1601,10 @@ pmc_process_csw_out(struct thread *td)
if (pm->pm_pcpu_state[cpu].pps_stalled == 0)
pcd->pcd_stop_pmc(cpu, adjri);
KASSERT(counter_u64_fetch(pm->pm_runcount) > 0,
("[pmc,%d] pm=%p runcount %ld", __LINE__, (void *) pm,
(unsigned long)counter_u64_fetch(pm->pm_runcount)));
/* reduce this PMC's runcount */
counter_u64_add(pm->pm_runcount, -1);
@ -2725,7 +2734,7 @@ pmc_destroy_pmc_descriptor(struct pmc *pm)
static void
pmc_wait_for_pmc_idle(struct pmc *pm)
{
#ifdef HWPMC_DEBUG
#ifdef INVARIANTS
volatile int maxloop;
maxloop = 100 * pmc_cpu_max();
@ -2737,7 +2746,7 @@ pmc_wait_for_pmc_idle(struct pmc *pm)
pmclog_flush(pm->pm_owner, 1);
while (counter_u64_fetch(pm->pm_runcount) > 0) {
pmclog_flush(pm->pm_owner, 1);
#ifdef HWPMC_DEBUG
#ifdef INVARIANTS
maxloop--;
KASSERT(maxloop > 0,
("[pmc,%d] (ri%d, rc%ld) waiting too long for "
@ -4657,7 +4666,7 @@ pmc_post_callchain_callback(void)
*/
static int
pmc_add_sample(int ring, struct pmc *pm, struct trapframe *tf)
pmc_add_sample(ring_type_t ring, struct pmc *pm, struct trapframe *tf)
{
int error, cpu, callchaindepth, inuserspace;
struct thread *td;
@ -4672,18 +4681,15 @@ pmc_add_sample(int ring, struct pmc *pm, struct trapframe *tf)
cpu = curcpu;
psb = pmc_pcpu[cpu]->pc_sb[ring];
inuserspace = TRAPF_USERMODE(tf);
ps = psb->ps_write;
if (ps->ps_nsamples == PMC_SAMPLE_INUSE) {
counter_u64_add(ps->ps_pmc->pm_runcount, -1);
counter_u64_add(pmc_stats.pm_overwrites, 1);
ps->ps_nsamples = 0;
} else if (ps->ps_nsamples) { /* in use, reader hasn't caught up */
ps = PMC_PROD_SAMPLE(psb);
if (psb->ps_considx != psb->ps_prodidx &&
ps->ps_nsamples) { /* in use, reader hasn't caught up */
pm->pm_pcpu_state[cpu].pps_stalled = 1;
counter_u64_add(pmc_stats.pm_intr_bufferfull, 1);
PMCDBG6(SAM,INT,1,"(spc) cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d",
cpu, pm, (void *) tf, inuserspace,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
(int) (psb->ps_prodidx & pmc_sample_mask),
(int) (psb->ps_considx & pmc_sample_mask));
callchaindepth = 1;
error = ENOMEM;
goto done;
@ -4692,14 +4698,8 @@ pmc_add_sample(int ring, struct pmc *pm, struct trapframe *tf)
/* Fill in entry. */
PMCDBG6(SAM,INT,1,"cpu=%d pm=%p tf=%p um=%d wr=%d rd=%d", cpu, pm,
(void *) tf, inuserspace,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
KASSERT(counter_u64_fetch(pm->pm_runcount) >= 0,
("[pmc,%d] pm=%p runcount %ld", __LINE__, (void *) pm,
(unsigned long)counter_u64_fetch(pm->pm_runcount)));
counter_u64_add(pm->pm_runcount, 1); /* hold onto PMC */
(int) (psb->ps_prodidx & pmc_sample_mask),
(int) (psb->ps_considx & pmc_sample_mask));
td = curthread;
ps->ps_pmc = pm;
@ -4707,13 +4707,14 @@ pmc_add_sample(int ring, struct pmc *pm, struct trapframe *tf)
ps->ps_pid = td->td_proc->p_pid;
ps->ps_tid = td->td_tid;
ps->ps_tsc = pmc_rdtsc();
ps->ps_ticks = ticks;
ps->ps_cpu = cpu;
ps->ps_flags = inuserspace ? PMC_CC_F_USERSPACE : 0;
callchaindepth = (pm->pm_flags & PMC_F_CALLCHAIN) ?
pmc_callchaindepth : 1;
MPASS(ps->ps_pc != NULL);
if (callchaindepth == 1)
ps->ps_pc[0] = PMC_TRAPFRAME_TO_PC(tf);
else {
@ -4727,26 +4728,27 @@ pmc_add_sample(int ring, struct pmc *pm, struct trapframe *tf)
callchaindepth, tf);
} else {
pmc_post_callchain_callback();
callchaindepth = PMC_SAMPLE_INUSE;
callchaindepth = PMC_USER_CALLCHAIN_PENDING;
}
}
ps->ps_nsamples = callchaindepth; /* mark entry as in use */
if (ring == PMC_UR) {
ps->ps_nsamples_actual = callchaindepth; /* mark entry as in use */
ps->ps_nsamples = PMC_SAMPLE_INUSE;
ps->ps_nsamples = PMC_USER_CALLCHAIN_PENDING;
} else
ps->ps_nsamples = callchaindepth; /* mark entry as in use */
/* increment write pointer, modulo ring buffer size */
ps++;
if (ps == psb->ps_fence)
psb->ps_write = psb->ps_samples;
else
psb->ps_write = ps;
KASSERT(counter_u64_fetch(pm->pm_runcount) >= 0,
("[pmc,%d] pm=%p runcount %ld", __LINE__, (void *) pm,
(unsigned long)counter_u64_fetch(pm->pm_runcount)));
counter_u64_add(pm->pm_runcount, 1); /* hold onto PMC */
/* increment write pointer */
psb->ps_prodidx++;
done:
/* mark CPU as needing processing */
if (callchaindepth != PMC_SAMPLE_INUSE)
if (callchaindepth != PMC_USER_CALLCHAIN_PENDING)
DPCPU_SET(pmc_sampled, 1);
return (error);
@ -4785,14 +4787,15 @@ pmc_capture_user_callchain(int cpu, int ring, struct trapframe *tf)
{
struct pmc *pm;
struct thread *td;
struct pmc_sample *ps, *ps_end;
struct pmc_sample *ps;
struct pmc_samplebuffer *psb;
int nsamples, nrecords, pass;
uint64_t considx, prodidx;
int nsamples, nrecords, pass, iter;
#ifdef INVARIANTS
int ncallchains;
int nfree;
int start_ticks = ticks;
#endif
psb = pmc_pcpu[cpu]->pc_sb[ring];
td = curthread;
@ -4810,29 +4813,30 @@ pmc_capture_user_callchain(int cpu, int ring, struct trapframe *tf)
if (ring == PMC_UR)
nrecords = atomic_readandclear_32(&td->td_pmcpend);
for (iter = 0, considx = psb->ps_considx, prodidx = psb->ps_prodidx;
considx < prodidx && iter < pmc_nsamples; considx++, iter++) {
ps = PMC_CONS_SAMPLE_OFF(psb, considx);
/*
* Iterate through all deferred callchain requests.
* Walk from the current read pointer to the current
* write pointer.
*/
ps = psb->ps_read;
ps_end = psb->ps_write;
do {
#ifdef INVARIANTS
if (ps->ps_nsamples == PMC_SAMPLE_FREE) {
nfree++;
goto next;
continue;
}
if ((ps->ps_pmc == NULL) ||
(ps->ps_pmc->pm_state != PMC_STATE_RUNNING))
nfree++;
#endif
if (ps->ps_nsamples != PMC_SAMPLE_INUSE)
goto next;
if (ps->ps_td != td)
goto next;
if (ps->ps_td != td ||
ps->ps_nsamples == PMC_USER_CALLCHAIN_PENDING ||
ps->ps_pmc->pm_state != PMC_STATE_RUNNING)
continue;
KASSERT(ps->ps_cpu == cpu,
("[pmc,%d] cpu mismatch ps_cpu=%d pcpu=%d", __LINE__,
@ -4865,15 +4869,28 @@ pmc_capture_user_callchain(int cpu, int ring, struct trapframe *tf)
if (__predict_true(nsamples < pmc_callchaindepth - 1))
nsamples += pmc_save_user_callchain(ps->ps_pc + nsamples,
pmc_callchaindepth - nsamples - 1, tf);
wmb();
ps->ps_nsamples = nsamples;
/*
* We have to prevent hardclock from potentially overwriting
* this sample between when we read the value and when we set
* it
*/
spinlock_enter();
/*
* Verify that the sample hasn't been dropped in the meantime
*/
if (ps->ps_nsamples == PMC_USER_CALLCHAIN_PENDING) {
ps->ps_nsamples = nsamples;
/*
* If we couldn't get a sample, simply drop the reference
*/
if (nsamples == 0)
counter_u64_add(pm->pm_runcount, -1);
}
spinlock_exit();
if (nrecords-- == 1)
break;
next:
/* increment the pointer, modulo sample ring size */
if (++ps == psb->ps_fence)
ps = psb->ps_samples;
} while (ps != ps_end);
}
if (__predict_false(ring == PMC_UR && td->td_pmcpend)) {
if (pass == 0) {
pass = 1;
@ -4884,60 +4901,20 @@ next:
}
#ifdef INVARIANTS
if (ring == PMC_HR)
KASSERT(ncallchains > 0 || nfree > 0,
("[pmc,%d] cpu %d didn't find a sample to collect", __LINE__,
cpu));
if ((ticks - start_ticks) > hz)
log(LOG_ERR, "%s took %d ticks\n", __func__, (ticks - start_ticks));
#endif
/* mark CPU as needing processing */
DPCPU_SET(pmc_sampled, 1);
}
static void
pmc_flush_ring(int cpu, int ring)
{
struct pmc *pm;
struct pmc_sample *ps;
struct pmc_samplebuffer *psb;
int n;
psb = pmc_pcpu[cpu]->pc_sb[ring];
for (n = 0; n < pmc_nsamples; n++) { /* bound on #iterations */
ps = psb->ps_read;
if (ps->ps_nsamples == PMC_SAMPLE_FREE)
goto next;
pm = ps->ps_pmc;
counter_u64_add(pm->pm_runcount, -1);
ps->ps_nsamples = PMC_SAMPLE_FREE;
/* increment read pointer, modulo sample size */
next:
if (++ps == psb->ps_fence)
psb->ps_read = psb->ps_samples;
else
psb->ps_read = ps;
}
}
void
pmc_flush_samples(int cpu)
{
int n;
for (n = 0; n < PMC_NUM_SR; n++)
pmc_flush_ring(cpu, n);
}
/*
* Process saved PC samples.
*/
static void
pmc_process_samples(int cpu, int ring)
pmc_process_samples(int cpu, ring_type_t ring)
{
struct pmc *pm;
int adjri, n;
@ -4946,20 +4923,25 @@ pmc_process_samples(int cpu, int ring)
struct pmc_sample *ps;
struct pmc_classdep *pcd;
struct pmc_samplebuffer *psb;
uint64_t delta;
KASSERT(PCPU_GET(cpuid) == cpu,
("[pmc,%d] not on the correct CPU pcpu=%d cpu=%d", __LINE__,
PCPU_GET(cpuid), cpu));
psb = pmc_pcpu[cpu]->pc_sb[ring];
delta = psb->ps_prodidx - psb->ps_considx;
MPASS(delta <= pmc_nsamples);
MPASS(psb->ps_considx <= psb->ps_prodidx);
for (n = 0; psb->ps_considx < psb->ps_prodidx; psb->ps_considx++, n++) {
ps = PMC_CONS_SAMPLE(psb);
for (n = 0; n < pmc_nsamples; n++) { /* bound on #iterations */
ps = psb->ps_read;
if (ps->ps_nsamples == PMC_SAMPLE_FREE)
break;
if (__predict_false(ps->ps_nsamples == PMC_SAMPLE_FREE))
continue;
pm = ps->ps_pmc;
/* skip non-running samples */
if (pm->pm_state != PMC_STATE_RUNNING)
goto entrydone;
KASSERT(counter_u64_fetch(pm->pm_runcount) > 0,
("[pmc,%d] pm=%p runcount %ld", __LINE__, (void *) pm,
@ -4971,12 +4953,19 @@ pmc_process_samples(int cpu, int ring)
("[pmc,%d] pmc=%p non-sampling mode=%d", __LINE__,
pm, PMC_TO_MODE(pm)));
/* Ignore PMCs that have been switched off */
if (pm->pm_state != PMC_STATE_RUNNING)
goto entrydone;
/* If there is a pending AST wait for completion */
if (ps->ps_nsamples == PMC_SAMPLE_INUSE) {
if (ps->ps_nsamples == PMC_USER_CALLCHAIN_PENDING) {
/* if sample is more than 65 ms old, drop it */
if (ticks - ps->ps_ticks > (hz >> 4)) {
/*
* track how often we hit this as it will
* preferentially lose user samples
* for long running system calls
*/
counter_u64_add(pmc_stats.pm_overwrites, 1);
goto entrydone;
}
/* Need a rescan at a later time. */
DPCPU_SET(pmc_sampled, 1);
break;
@ -4984,8 +4973,8 @@ pmc_process_samples(int cpu, int ring)
PMCDBG6(SAM,OPS,1,"cpu=%d pm=%p n=%d fl=%x wr=%d rd=%d", cpu,
pm, ps->ps_nsamples, ps->ps_flags,
(int) (psb->ps_write - psb->ps_samples),
(int) (psb->ps_read - psb->ps_samples));
(int) (psb->ps_prodidx & pmc_sample_mask),
(int) (psb->ps_considx & pmc_sample_mask));
/*
* If this is a process-mode PMC that is attached to
@ -5008,13 +4997,11 @@ pmc_process_samples(int cpu, int ring)
entrydone:
ps->ps_nsamples = 0; /* mark entry as free */
counter_u64_add(pm->pm_runcount, -1);
KASSERT(counter_u64_fetch(pm->pm_runcount) > 0,
("[pmc,%d] pm=%p runcount %ld", __LINE__, (void *) pm,
(unsigned long)counter_u64_fetch(pm->pm_runcount)));
/* increment read pointer, modulo sample size */
if (++ps == psb->ps_fence)
psb->ps_read = psb->ps_samples;
else
psb->ps_read = ps;
counter_u64_add(pm->pm_runcount, -1);
}
counter_u64_add(pmc_stats.pm_log_sweeps, 1);
@ -5197,11 +5184,11 @@ pmc_process_exit(void *arg __unused, struct proc *p)
}
}
counter_u64_add(pm->pm_runcount, -1);
KASSERT((int) counter_u64_fetch(pm->pm_runcount) >= 0,
KASSERT((int64_t) counter_u64_fetch(pm->pm_runcount) > 0,
("[pmc,%d] runcount is %d", __LINE__, ri));
counter_u64_add(pm->pm_runcount, -1);
(void) pcd->pcd_config_pmc(cpu, adjri, NULL);
}
@ -5583,6 +5570,7 @@ pmc_initialize(void)
"range.\n", pmc_nsamples);
pmc_nsamples = PMC_NSAMPLES;
}
pmc_sample_mask = pmc_nsamples-1;
if (pmc_callchaindepth <= 0 ||
pmc_callchaindepth > PMC_CALLCHAIN_DEPTH_MAX) {
@ -5658,8 +5646,6 @@ pmc_initialize(void)
sb = malloc_domain(sizeof(struct pmc_samplebuffer) +
pmc_nsamples * sizeof(struct pmc_sample), M_PMC, domain,
M_WAITOK|M_ZERO);
sb->ps_read = sb->ps_write = sb->ps_samples;
sb->ps_fence = sb->ps_samples + pmc_nsamples;
KASSERT(pmc_pcpu[cpu] != NULL,
("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
@ -5676,8 +5662,6 @@ pmc_initialize(void)
sb = malloc_domain(sizeof(struct pmc_samplebuffer) +
pmc_nsamples * sizeof(struct pmc_sample), M_PMC, domain,
M_WAITOK|M_ZERO);
sb->ps_read = sb->ps_write = sb->ps_samples;
sb->ps_fence = sb->ps_samples + pmc_nsamples;
KASSERT(pmc_pcpu[cpu] != NULL,
("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));
@ -5694,8 +5678,6 @@ pmc_initialize(void)
sb = malloc_domain(sizeof(struct pmc_samplebuffer) +
pmc_nsamples * sizeof(struct pmc_sample), M_PMC, domain,
M_WAITOK|M_ZERO);
sb->ps_read = sb->ps_write = sb->ps_samples;
sb->ps_fence = sb->ps_samples + pmc_nsamples;
KASSERT(pmc_pcpu[cpu] != NULL,
("[pmc,%d] cpu=%d Null per-cpu data", __LINE__, cpu));

18
sys/sys/pmc.h
View File

@ -936,6 +936,8 @@ struct pmc_sample {
uint16_t ps_flags; /* other flags */
lwpid_t ps_tid; /* thread id */
pid_t ps_pid; /* process PID or -1 */
int ps_ticks; /* ticks at sample time */
/* pad */
struct thread *ps_td; /* which thread */
struct pmc *ps_pmc; /* interrupting PMC */
uintptr_t *ps_pc; /* (const) callchain start */
@ -943,16 +945,23 @@ struct pmc_sample {
};
#define PMC_SAMPLE_FREE ((uint16_t) 0)
#define PMC_SAMPLE_INUSE ((uint16_t) 0xFFFF)
#define PMC_USER_CALLCHAIN_PENDING ((uint16_t) 0xFFFF)
struct pmc_samplebuffer {
struct pmc_sample * volatile ps_read; /* read pointer */
struct pmc_sample * volatile ps_write; /* write pointer */
volatile uint64_t ps_prodidx; /* producer index */
volatile uint64_t ps_considx; /* consumer index */
uintptr_t *ps_callchains; /* all saved call chains */
struct pmc_sample *ps_fence; /* one beyond ps_samples[] */
struct pmc_sample ps_samples[]; /* array of sample entries */
};
#define PMC_CONS_SAMPLE(psb) \
(&(psb)->ps_samples[(psb)->ps_considx & pmc_sample_mask])
#define PMC_CONS_SAMPLE_OFF(psb, off) \
(&(psb)->ps_samples[(off) & pmc_sample_mask])
#define PMC_PROD_SAMPLE(psb) \
(&(psb)->ps_samples[(psb)->ps_prodidx & pmc_sample_mask])
/*
* struct pmc_cpustate
@ -1216,7 +1225,6 @@ int pmc_save_user_callchain(uintptr_t *_cc, int _maxsamples,
struct trapframe *_tf);
struct pmc_mdep *pmc_mdep_alloc(int nclasses);
void pmc_mdep_free(struct pmc_mdep *md);
void pmc_flush_samples(int cpu);
uint64_t pmc_rdtsc(void);
#endif /* _KERNEL */
#endif /* _SYS_PMC_H_ */

10
sys/sys/pmckern.h
View File

@ -67,10 +67,12 @@
#define PMC_FN_THR_EXIT_LOG 16
#define PMC_FN_PROC_CREATE_LOG 17
#define PMC_HR 0 /* Hardware ring buffer */
#define PMC_SR 1 /* Software ring buffer */
#define PMC_UR 2 /* userret ring buffer */
#define PMC_NUM_SR (PMC_UR+1)
typedef enum ring_type {
PMC_HR = 0, /* Hardware ring buffer */
PMC_SR = 1, /* Software ring buffer */
PMC_UR = 2, /* userret ring buffer */
PMC_NUM_SR = PMC_UR+1
} ring_type_t;
struct pmckern_procexec {
int pm_credentialschanged;