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fix assert and conditionally allow mutexes to be held across epoch_wait_preempt

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This commit is contained in:
Matt Macy 2018-06-24 18:57:06 +00:00
parent 503b10da57
commit 74333b3dee
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=335605
2 changed files with 13 additions and 13 deletions
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25
sys/kern/subr_epoch.c
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@ -375,9 +375,11 @@ epoch_block_handler_preempt(struct ck_epoch *global __unused, ck_epoch_record_t
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 __unused, ck_epoch_record_t
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;
locks = curthread->td_locks;
#endif
int locks __unused;
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);

1
sys/sys/epoch.h
View File

@ -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;