Author: mmacy
Date: Sun Jun 24 18:57:06 2018
New Revision: 335605
URL: https://svnweb.freebsd.org/changeset/base/335605
Log:
fix assert and conditionally allow mutexes to be held across
epoch_wait_preempt
Modified:
head/sys/kern/subr_epoch.c
head/sys/sys/epoch.h
Modified: head/sys/kern/subr_epoch.c
==============================================================================
--- head/sys/kern/subr_epoch.c Sun Jun 24 15:22:38 2018 (r335604)
+++ head/sys/kern/subr_epoch.c Sun Jun 24 18:57:06 2018 (r335605)
@@ -375,9 +375,11 @@ epoch_block_handler_preempt(struct ck_epoch *global __
struct turnstile *ts;
struct lock_object *lock;
int spincount, gen;
+ int locksheld __unused;
record = __containerof(cr, struct epoch_record, er_record);
td = curthread;
+ locksheld = td->td_locks;
spincount = 0;
counter_u64_add(block_count, 1);
if (record->er_cpuid != curcpu) {
@@ -470,8 +472,8 @@ epoch_block_handler_preempt(struct ck_epoch *global __
turnstile_unlock(ts, lock);
thread_lock(td);
critical_exit();
- KASSERT(td->td_locks == 0,
- ("%d locks held", td->td_locks));
+ KASSERT(td->td_locks == locksheld,
+ ("%d extra locks held", td->td_locks - locksheld));
}
}
/*
@@ -499,23 +501,20 @@ epoch_wait_preempt(epoch_t epoch)
int old_cpu;
int old_pinned;
u_char old_prio;
-#ifdef INVARIANTS
- int locks;
+ int locks __unused;
- locks = curthread->td_locks;
-#endif
-
MPASS(cold || epoch != NULL);
INIT_CHECK(epoch);
-
- MPASS(epoch->e_flags & EPOCH_PREEMPT);
- WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
- "epoch_wait() can sleep");
-
td = curthread;
+#ifdef INVARIANTS
+ locks = curthread->td_locks;
+ MPASS(epoch->e_flags & EPOCH_PREEMPT);
+ if ((epoch->e_flags & EPOCH_LOCKED) == 0)
+ WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,
+ "epoch_wait() can be long running");
KASSERT(td->td_epochnest == 0, ("epoch_wait() in the middle of an epoch
section"));
+#endif
thread_lock(td);
-
DROP_GIANT();
old_cpu = PCPU_GET(cpuid);
Modified: head/sys/sys/epoch.h
==============================================================================
--- head/sys/sys/epoch.h Sun Jun 24 15:22:38 2018 (r335604)
+++ head/sys/sys/epoch.h Sun Jun 24 18:57:06 2018 (r335605)
@@ -39,6 +39,7 @@ struct epoch;
typedef struct epoch *epoch_t;
#define EPOCH_PREEMPT 0x1
+#define EPOCH_LOCKED 0x2
extern epoch_t global_epoch;
extern epoch_t global_epoch_preempt;
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