Author: glebius
Date: Tue Oct 29 17:28:25 2019
New Revision: 354148
URL: https://svnweb.freebsd.org/changeset/base/354148
Log:
Merge td_epochnest with td_no_sleeping.
Epoch itself doesn't rely on the counter and it is provided
merely for sleeping subsystems to check it.
- In functions that sleep use THREAD_CAN_SLEEP() to assert
correctness. With EPOCH_TRACE compiled print epoch info.
- _sleep() was a wrong place to put the assertion for epoch,
right place is sleepq_add(), as there ways to call the
latter bypassing _sleep().
- Do not increase td_no_sleeping in non-preemptible epochs.
The critical section would trigger all possible safeguards,
no sleeping counter is extraneous.
Reviewed by: kib
Modified:
head/sys/kern/genoffset.c
head/sys/kern/kern_malloc.c
head/sys/kern/kern_synch.c
head/sys/kern/subr_epoch.c
head/sys/kern/subr_sleepqueue.c
head/sys/kern/subr_trap.c
Modified: head/sys/kern/genoffset.c
==============================================================================
--- head/sys/kern/genoffset.c Tue Oct 29 17:19:36 2019 (r354147)
+++ head/sys/kern/genoffset.c Tue Oct 29 17:28:25 2019 (r354148)
@@ -37,7 +37,6 @@ __FBSDID("$FreeBSD$");
#include <sys/proc.h>
OFFSYM(td_priority, thread, u_char);
-OFFSYM(td_epochnest, thread, u_char);
OFFSYM(td_critnest, thread, u_int);
OFFSYM(td_pinned, thread, int);
OFFSYM(td_owepreempt, thread, u_char);
Modified: head/sys/kern/kern_malloc.c
==============================================================================
--- head/sys/kern/kern_malloc.c Tue Oct 29 17:19:36 2019 (r354147)
+++ head/sys/kern/kern_malloc.c Tue Oct 29 17:28:25 2019 (r354148)
@@ -523,12 +523,13 @@ malloc_dbg(caddr_t *vap, size_t *sizep, struct malloc_
if (flags & M_WAITOK) {
KASSERT(curthread->td_intr_nesting_level == 0,
("malloc(M_WAITOK) in interrupt context"));
+ if (__predict_false(!THREAD_CAN_SLEEP())) {
#ifdef EPOCH_TRACE
- if (__predict_false(curthread->td_epochnest > 0))
epoch_trace_list(curthread);
#endif
- KASSERT(curthread->td_epochnest == 0,
- ("malloc(M_WAITOK) in epoch context"));
+ KASSERT(1,
+ ("malloc(M_WAITOK) with sleeping prohibited"));
+ }
}
KASSERT(curthread->td_critnest == 0 || SCHEDULER_STOPPED(),
("malloc: called with spinlock or critical section held"));
Modified: head/sys/kern/kern_synch.c
==============================================================================
--- head/sys/kern/kern_synch.c Tue Oct 29 17:19:36 2019 (r354147)
+++ head/sys/kern/kern_synch.c Tue Oct 29 17:28:25 2019 (r354148)
@@ -151,11 +151,6 @@ _sleep(void *ident, struct lock_object *lock, int prio
("sleeping without a lock"));
KASSERT(ident != NULL, ("_sleep: NULL ident"));
KASSERT(TD_IS_RUNNING(td), ("_sleep: curthread not running"));
-#ifdef EPOCH_TRACE
- if (__predict_false(curthread->td_epochnest > 0))
- epoch_trace_list(curthread);
-#endif
- KASSERT(td->td_epochnest == 0, ("sleeping in an epoch section"));
if (priority & PDROP)
KASSERT(lock != NULL && lock != &Giant.lock_object,
("PDROP requires a non-Giant lock"));
Modified: head/sys/kern/subr_epoch.c
==============================================================================
--- head/sys/kern/subr_epoch.c Tue Oct 29 17:19:36 2019 (r354147)
+++ head/sys/kern/subr_epoch.c Tue Oct 29 17:28:25 2019 (r354148)
@@ -377,7 +377,7 @@ _epoch_enter_preempt(epoch_t epoch, epoch_tracker_t et
epoch_trace_enter(td, epoch, et, file, line);
#endif
et->et_td = td;
- td->td_epochnest++;
+ THREAD_NO_SLEEPING();
critical_enter();
sched_pin();
td->td_pre_epoch_prio = td->td_priority;
@@ -390,13 +390,10 @@ _epoch_enter_preempt(epoch_t epoch, epoch_tracker_t et
void
epoch_enter(epoch_t epoch)
{
- struct thread *td;
epoch_record_t er;
MPASS(cold || epoch != NULL);
INIT_CHECK(epoch);
- td = curthread;
- td->td_epochnest++;
critical_enter();
er = epoch_currecord(epoch);
ck_epoch_begin(&er->er_record, NULL);
@@ -412,8 +409,7 @@ _epoch_exit_preempt(epoch_t epoch, epoch_tracker_t et
td = curthread;
critical_enter();
sched_unpin();
- MPASS(td->td_epochnest);
- td->td_epochnest--;
+ THREAD_SLEEPING_OK();
er = epoch_currecord(epoch);
MPASS(epoch->e_flags & EPOCH_PREEMPT);
MPASS(et != NULL);
@@ -435,13 +431,9 @@ _epoch_exit_preempt(epoch_t epoch, epoch_tracker_t et
void
epoch_exit(epoch_t epoch)
{
- struct thread *td;
epoch_record_t er;
INIT_CHECK(epoch);
- td = curthread;
- MPASS(td->td_epochnest);
- td->td_epochnest--;
er = epoch_currecord(epoch);
ck_epoch_end(&er->er_record, NULL);
critical_exit();
@@ -740,7 +732,7 @@ in_epoch_verbose(epoch_t epoch, int dump_onfail)
epoch_record_t er;
td = curthread;
- if (td->td_epochnest == 0)
+ if (THREAD_CAN_SLEEP())
return (0);
if (__predict_false((epoch) == NULL))
return (0);
Modified: head/sys/kern/subr_sleepqueue.c
==============================================================================
--- head/sys/kern/subr_sleepqueue.c Tue Oct 29 17:19:36 2019
(r354147)
+++ head/sys/kern/subr_sleepqueue.c Tue Oct 29 17:28:25 2019
(r354148)
@@ -80,6 +80,9 @@ __FBSDID("$FreeBSD$");
#include <sys/stack.h>
#include <sys/sysctl.h>
#include <sys/time.h>
+#ifdef EPOCH_TRACE
+#include <sys/epoch.h>
+#endif
#include <machine/atomic.h>
@@ -315,9 +318,14 @@ sleepq_add(void *wchan, struct lock_object *lock, cons
MPASS((queue >= 0) && (queue < NR_SLEEPQS));
/* If this thread is not allowed to sleep, die a horrible death. */
- KASSERT(THREAD_CAN_SLEEP(),
- ("%s: td %p to sleep on wchan %p with sleeping prohibited",
- __func__, td, wchan));
+ if (__predict_false(!THREAD_CAN_SLEEP())) {
+#ifdef EPOCH_TRACE
+ epoch_trace_list(curthread);
+#endif
+ KASSERT(1,
+ ("%s: td %p to sleep on wchan %p with sleeping prohibited",
+ __func__, td, wchan));
+ }
/* Look up the sleep queue associated with the wait channel 'wchan'. */
sq = sleepq_lookup(wchan);
Modified: head/sys/kern/subr_trap.c
==============================================================================
--- head/sys/kern/subr_trap.c Tue Oct 29 17:19:36 2019 (r354147)
+++ head/sys/kern/subr_trap.c Tue Oct 29 17:28:25 2019 (r354148)
@@ -166,12 +166,6 @@ userret(struct thread *td, struct trapframe *frame)
WITNESS_WARN(WARN_PANIC, NULL, "userret: returning");
KASSERT(td->td_critnest == 0,
("userret: Returning in a critical section"));
-#ifdef EPOCH_TRACE
- if (__predict_false(curthread->td_epochnest > 0))
- epoch_trace_list(curthread);
-#endif
- KASSERT(td->td_epochnest == 0,
- ("userret: Returning in an epoch section"));
KASSERT(td->td_locks == 0,
("userret: Returning with %d locks held", td->td_locks));
KASSERT(td->td_rw_rlocks == 0,
@@ -185,8 +179,12 @@ userret(struct thread *td, struct trapframe *frame)
td->td_lk_slocks));
KASSERT((td->td_pflags & TDP_NOFAULTING) == 0,
("userret: Returning with pagefaults disabled"));
- KASSERT(THREAD_CAN_SLEEP(),
- ("userret: Returning with sleep disabled"));
+ if (__predict_false(!THREAD_CAN_SLEEP())) {
+#ifdef EPOCH_TRACE
+ epoch_trace_list(curthread);
+#endif
+ KASSERT(1, ("userret: Returning with sleep disabled"));
+ }
KASSERT(td->td_pinned == 0 || (td->td_pflags & TDP_CALLCHAIN) != 0,
("userret: Returning with with pinned thread"));
KASSERT(td->td_vp_reserv == 0,
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