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Code Issues

Fixed bug CORE-2698 : Infinite wait in LocksCache::get

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This commit is contained in:
hvlad 2009-10-20 08:32:45 +00:00
parent 20cc44d4d3
commit 7a6ea06189
1 changed files with 35 additions and 14 deletions
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49
src/jrd/LocksCache.h
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@ -67,15 +67,13 @@ public:
return reinterpret_cast<UCHAR*> (&cached_lock->lck_key); return reinterpret_cast<UCHAR*> (&cached_lock->lck_key);
} }
void setLockKey(thread_db *tdbb, const UCHAR* key) bool setLockKey(thread_db *tdbb, const UCHAR* key)
{ {
while (!tryReleaseLock(tdbb)) if (!tryReleaseLock(tdbb))
{ return false;
lock(tdbb, LCK_write, LCK_WAIT);
unlock(tdbb, LCK_write);
}
memcpy(&cached_lock->lck_key, key, cached_lock->lck_length); memcpy(&cached_lock->lck_key, key, cached_lock->lck_length);
return true;
} }
static const KeyHolder generate(const void*, const CachedLock* lock) { static const KeyHolder generate(const void*, const CachedLock* lock) {
@ -154,17 +152,40 @@ GlobalRWLock* LocksCache<LockClass>::get(thread_db *tdbb, const UCHAR* key)
else else
{ {
QUE que_inst = m_lru.que_backward; QUE que_inst = m_lru.que_backward;
QUE_DELETE((*que_inst)); int tries = MIN(m_capacity / 2, 16);
lock = (LockClass*) ((SCHAR*) que_inst - OFFSET (LockClass*, m_lru)); while (true)
{
lock = (LockClass*) ((SCHAR*) que_inst - OFFSET (LockClass*, m_lru));
bool found = (m_sortedLocks.find(KeyHolder(lock->getLockKey(), m_lockLen), pos)); bool found = (m_sortedLocks.find(KeyHolder(lock->getLockKey(), m_lockLen), pos));
fb_assert(found); fb_assert(found);
m_sortedLocks.remove(pos); if (lock->setLockKey(tdbb, key))
lock->setLockKey(tdbb, key); {
m_sortedLocks.remove(pos);
QUE_DELETE((*que_inst));
found = (m_sortedLocks.find(KeyHolder(key, m_lockLen), pos)); found = (m_sortedLocks.find(KeyHolder(key, m_lockLen), pos));
fb_assert(!found); fb_assert(!found);
break;
}
else if (tries == 0)
{
m_capacity++;
lock = FB_NEW (m_pool) LockClass(tdbb, m_pool, m_lockType, m_lockLen, key);
found = (m_sortedLocks.find(KeyHolder(key, m_lockLen), pos));
fb_assert(!found);
break;
}
else
{
que_inst = que_inst->que_backward;
tries--;
// move busy lock to the head of LRU queue
QUE_DELETE(lock->m_lru);
QUE_INSERT(m_lru, lock->m_lru);
}
}
} }
m_sortedLocks.insert(pos, lock); m_sortedLocks.insert(pos, lock);
} }