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Code Issues

Fixed bug CORE-1985 : Lock manager code may create 100% CPU load for some time

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This commit is contained in:
hvlad 2008-07-09 07:52:50 +00:00
parent bda59af553
commit 40f3722373
1 changed files with 12 additions and 6 deletions
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18
src/lock/lock.cpp
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@ -3648,8 +3648,9 @@ USHORT LockManager::wait_for_request(thread_db* tdbb, lrq* request, SSHORT lck_w
ULONG repost_counter = 0;
#endif
int ret;
while (true) {
int ret = FB_FAILURE;
// Before starting to wait - look to see if someone resolved
// the request for us - if so we're out easy!
@ -3698,6 +3699,7 @@ USHORT LockManager::wait_for_request(thread_db* tdbb, lrq* request, SSHORT lck_w
break;
}
acquire_shmem(owner_offset);
// See if we wokeup due to another owner deliberately waking us up
// ret==FB_SUCCESS --> we were deliberately woken up
// ret==FB_FAILURE --> we still don't know why we woke up
@ -3706,6 +3708,12 @@ USHORT LockManager::wait_for_request(thread_db* tdbb, lrq* request, SSHORT lck_w
// by another owner is OWN_wakeup set. This is the only FB_SUCCESS case.
owner = (own*) SRQ_ABS_PTR(owner_offset);
if (ret == FB_SUCCESS)
{
event_ptr = &owner->own_wakeup;
value = ISC_event_clear(event_ptr);
}
if (owner->own_flags & OWN_wakeup)
ret = FB_SUCCESS;
else
@ -3724,14 +3732,15 @@ USHORT LockManager::wait_for_request(thread_db* tdbb, lrq* request, SSHORT lck_w
// wakeup due to timing differences (we use seconds here,
// ISC_event_wait() uses finer granularity)
if ((ret != FB_SUCCESS) && (current_time + 1 < timeout)) {
if ((ret != FB_SUCCESS) && (current_time + 1 < timeout))
{
release_shmem(owner_offset);
continue;
}
// We apparently woke up for some real reason.
// Make sure everyone is still with us. Then see if we're still blocked.
acquire_shmem(owner_offset);
request = (lrq*) SRQ_ABS_PTR(request_offset);
lock = (lbl*) SRQ_ABS_PTR(lock_offset);
owner = (own*) SRQ_ABS_PTR(owner_offset);
@ -3770,9 +3779,6 @@ USHORT LockManager::wait_for_request(thread_db* tdbb, lrq* request, SSHORT lck_w
// Handle lock event first
if (ret == FB_SUCCESS)
{
event_ptr = &owner->own_wakeup;
value = ISC_event_clear(event_ptr);
// Someone posted our wakeup event, but DIDN'T grant our request.
// Re-post what we're blocking on and continue to wait.
// This could happen if the lock was granted to a different request,