int
pmclog_deconfigure_log(struct pmc_owner *po)
{
int error;
struct pmclog_buffer *lb;
PMCDBG1(LOG,CFG,1, "de-config po=%p", po);
if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
return (EINVAL);
KASSERT(po->po_sscount == 0,
("[pmclog,%d] po=%p still owning SS PMCs", __LINE__, po));
KASSERT(po->po_file != NULL,
("[pmclog,%d] po=%p no log file", __LINE__, po));
/* stop the kthread, this will reset the 'OWNS_LOGFILE' flag */
pmclog_stop_kthread(po);
KASSERT(po->po_kthread == NULL,
("[pmclog,%d] po=%p kthread not stopped", __LINE__, po));
/* return all queued log buffers to the global pool */
while ((lb = TAILQ_FIRST(&po->po_logbuffers)) != NULL) {
TAILQ_REMOVE(&po->po_logbuffers, lb, plb_next);
PMCLOG_INIT_BUFFER_DESCRIPTOR(lb);
mtx_lock_spin(&pmc_bufferlist_mtx);
TAILQ_INSERT_HEAD(&pmc_bufferlist, lb, plb_next);
mtx_unlock_spin(&pmc_bufferlist_mtx);
}
/* return the 'current' buffer to the global pool */
if ((lb = po->po_curbuf) != NULL) {
PMCLOG_INIT_BUFFER_DESCRIPTOR(lb);
mtx_lock_spin(&pmc_bufferlist_mtx);
TAILQ_INSERT_HEAD(&pmc_bufferlist, lb, plb_next);
mtx_unlock_spin(&pmc_bufferlist_mtx);
}
/* drop a reference to the fd */
if (po->po_file != NULL) {
error = fdrop(po->po_file, curthread);
po->po_file = NULL;
} else
error = 0;
po->po_error = 0;
return (error);
}
void
pmclog_initialize()
{
int n;
struct pmclog_buffer *plb;
if (pmclog_buffer_size <= 0) {
(void) printf("hwpmc: tunable logbuffersize=%d must be "
"greater than zero.\n", pmclog_buffer_size);
pmclog_buffer_size = PMC_LOG_BUFFER_SIZE;
}
if (pmc_nlogbuffers <= 0) {
(void) printf("hwpmc: tunable nlogbuffers=%d must be greater "
"than zero.\n", pmc_nlogbuffers);
pmc_nlogbuffers = PMC_NLOGBUFFERS;
}
/* create global pool of log buffers */
for (n = 0; n < pmc_nlogbuffers; n++) {
plb = malloc(1024 * pmclog_buffer_size, M_PMC,
M_WAITOK|M_ZERO);
PMCLOG_INIT_BUFFER_DESCRIPTOR(plb);
TAILQ_INSERT_HEAD(&pmc_bufferlist, plb, plb_next);
}
mtx_init(&pmc_bufferlist_mtx, "pmc-buffer-list", "pmc-leaf",
MTX_SPIN);
mtx_init(&pmc_kthread_mtx, "pmc-kthread", "pmc-sleep", MTX_DEF);
}
static void
pmclog_loop(void *arg)
{
int error;
struct pmc_owner *po;
struct pmclog_buffer *lb;
struct proc *p;
struct ucred *ownercred;
struct ucred *mycred;
struct thread *td;
struct uio auio;
struct iovec aiov;
size_t nbytes;
po = (struct pmc_owner *) arg;
p = po->po_owner;
td = curthread;
mycred = td->td_ucred;
PROC_LOCK(p);
ownercred = crhold(p->p_ucred);
PROC_UNLOCK(p);
PMCDBG(LOG,INI,1, "po=%p kt=%p", po, po->po_kthread);
KASSERT(po->po_kthread == curthread->td_proc,
("[pmclog,%d] proc mismatch po=%p po/kt=%p curproc=%p", __LINE__,
po, po->po_kthread, curthread->td_proc));
lb = NULL;
/*
* Loop waiting for I/O requests to be added to the owner
* struct's queue. The loop is exited when the log file
* is deconfigured.
*/
mtx_lock(&pmc_kthread_mtx);
for (;;) {
/* check if we've been asked to exit */
if ((po->po_flags & PMC_PO_OWNS_LOGFILE) == 0)
break;
if (lb == NULL) { /* look for a fresh buffer to write */
mtx_lock_spin(&po->po_mtx);
if ((lb = TAILQ_FIRST(&po->po_logbuffers)) == NULL) {
mtx_unlock_spin(&po->po_mtx);
/* No more buffers and shutdown required. */
if (po->po_flags & PMC_PO_SHUTDOWN) {
mtx_unlock(&pmc_kthread_mtx);
/*
* Close the file to get PMCLOG_EOF
* error in pmclog(3).
*/
fo_close(po->po_file, curthread);
mtx_lock(&pmc_kthread_mtx);
break;
}
(void) msleep(po, &pmc_kthread_mtx, PWAIT,
"pmcloop", 0);
continue;
}
TAILQ_REMOVE(&po->po_logbuffers, lb, plb_next);
mtx_unlock_spin(&po->po_mtx);
}
mtx_unlock(&pmc_kthread_mtx);
/* process the request */
PMCDBG(LOG,WRI,2, "po=%p base=%p ptr=%p", po,
lb->plb_base, lb->plb_ptr);
/* change our thread's credentials before issuing the I/O */
aiov.iov_base = lb->plb_base;
aiov.iov_len = nbytes = lb->plb_ptr - lb->plb_base;
auio.uio_iov = &aiov;
auio.uio_iovcnt = 1;
auio.uio_offset = -1;
auio.uio_resid = nbytes;
auio.uio_rw = UIO_WRITE;
auio.uio_segflg = UIO_SYSSPACE;
auio.uio_td = td;
/* switch thread credentials -- see kern_ktrace.c */
td->td_ucred = ownercred;
error = fo_write(po->po_file, &auio, ownercred, 0, td);
td->td_ucred = mycred;
if (error) {
/* XXX some errors are recoverable */
/* send a SIGIO to the owner and exit */
PROC_LOCK(p);
kern_psignal(p, SIGIO);
PROC_UNLOCK(p);
mtx_lock(&pmc_kthread_mtx);
po->po_error = error; /* save for flush log */
PMCDBG(LOG,WRI,2, "po=%p error=%d", po, error);
break;
}
mtx_lock(&pmc_kthread_mtx);
/* put the used buffer back into the global pool */
PMCLOG_INIT_BUFFER_DESCRIPTOR(lb);
mtx_lock_spin(&pmc_bufferlist_mtx);
TAILQ_INSERT_HEAD(&pmc_bufferlist, lb, plb_next);
mtx_unlock_spin(&pmc_bufferlist_mtx);
lb = NULL;
}
wakeup_one(po->po_kthread);
po->po_kthread = NULL;
mtx_unlock(&pmc_kthread_mtx);
/* return the current I/O buffer to the global pool */
if (lb) {
PMCLOG_INIT_BUFFER_DESCRIPTOR(lb);
mtx_lock_spin(&pmc_bufferlist_mtx);
TAILQ_INSERT_HEAD(&pmc_bufferlist, lb, plb_next);
mtx_unlock_spin(&pmc_bufferlist_mtx);
}
/*
* Exit this thread, signalling the waiter
*/
crfree(ownercred);
kproc_exit(0);
}
