Commit 87eca1e0 authored by Julien Muchembled's avatar Julien Muchembled

client: replace global load lock by a per-oid one

parent c7cdcf87
......@@ -17,7 +17,7 @@
import heapq
import random
import time
from collections import defaultdict
try:
from ZODB._compat import dumps, loads, _protocol
except ImportError:
......@@ -79,7 +79,7 @@ class Application(ThreadedApplication):
# no self-assigned UUID, primary master will supply us one
self._cache = ClientCache() if cache_size is None else \
ClientCache(max_size=cache_size)
self._loading_oid = None
self._loading = defaultdict(lambda: (Lock(), []))
self.new_oid_list = ()
self.last_oid = '\0' * 8
self.storage_event_handler = storage.StorageEventHandler(self)
......@@ -90,19 +90,13 @@ class Application(ThreadedApplication):
self.notifications_handler = master.PrimaryNotificationsHandler( self)
self._txn_container = TransactionContainer()
# Lock definition :
# _load_lock is used to make loading and storing atomic
lock = Lock()
self._load_lock_acquire = lock.acquire
self._load_lock_release = lock.release
# _oid_lock is used in order to not call multiple oid
# generation at the same time
lock = Lock()
self._oid_lock_acquire = lock.acquire
self._oid_lock_release = lock.release
lock = Lock()
# _cache_lock is used for the client cache
self._cache_lock_acquire = lock.acquire
self._cache_lock_release = lock.release
self._cache_lock = Lock()
# _connecting_to_master_node is used to prevent simultaneous master
# node connection attempts
self._connecting_to_master_node = Lock()
......@@ -398,21 +392,28 @@ class Application(ThreadedApplication):
"""
# TODO:
# - rename parameters (here? and in handlers & packet definitions)
acquire = self._cache_lock_acquire
release = self._cache_lock_release
# XXX: Consider using a more fine-grained lock.
self._load_lock_acquire()
try:
acquire()
acquired = False
lock = self._cache_lock
try:
while 1:
with lock:
result = self._loadFromCache(oid, tid, before_tid)
if result:
return result
self._loading_oid = oid
self._loading_invalidated = []
finally:
release()
load_lock = self._loading[oid][0]
acquired = load_lock.acquire(0)
# Several concurrent cache misses for the same oid are probably
# for the same tid so we use a per-oid lock to avoid asking the
# same data to the storage node.
if acquired:
# The first thread does load from storage,
# and fills cache with the response.
break
# The other threads wait for the first one to complete and
# loop, possibly resulting in a new cache miss if a different
# tid is actually wanted or if the data was too big.
with load_lock:
pass
# While the cache lock is released, an arbitrary number of
# invalidations may be processed, for this oid or not. And at this
# precise moment, if both tid and before_tid are None (which is
......@@ -428,20 +429,24 @@ class Application(ThreadedApplication):
# we got from master.
before_tid = p64(u64(self.last_tid) + 1)
data, tid, next_tid, _ = self._loadFromStorage(oid, tid, before_tid)
acquire()
try:
if self._loading_oid:
with lock:
loading = self._loading.pop(oid, None)
if loading:
assert loading[0] is load_lock
if not next_tid:
for t in self._loading_invalidated:
for t in loading[1]:
if tid < t:
next_tid = t
break
self._cache.store(oid, data, tid, next_tid)
# Else, we just reconnected to the master.
finally:
release()
finally:
self._load_lock_release()
load_lock.release()
except:
if acquired:
with lock:
self._loading.pop(oid, None)
load_lock.release()
raise
return data, tid, next_tid
def _loadFromStorage(self, oid, at_tid, before_tid):
......@@ -986,11 +991,8 @@ class Application(ThreadedApplication):
# It should not be otherwise required (clients should be free to load
# old data as long as it is available in cache, event if it was pruned
# by a pack), so don't bother invalidating on other clients.
self._cache_lock_acquire()
try:
with self._cache_lock:
self._cache.clear()
finally:
self._cache_lock_release()
def getLastTID(self, oid):
return self.load(oid)[1]
......
......@@ -52,8 +52,7 @@ class PrimaryNotificationsHandler(MTEventHandler):
# Either we're connecting or we already know the last tid
# via invalidations.
assert app.master_conn is None, app.master_conn
app._cache_lock_acquire()
try:
with app._cache_lock:
if app_last_tid < ltid:
app._cache.clear_current()
# In the past, we tried not to invalidate the
......@@ -67,9 +66,7 @@ class PrimaryNotificationsHandler(MTEventHandler):
app._cache.clear()
# Make sure a parallel load won't refill the cache
# with garbage.
app._loading_oid = app._loading_invalidated = None
finally:
app._cache_lock_release()
app._loading.clear()
db = app.getDB()
db is None or db.invalidateCache()
app.last_tid = ltid
......@@ -80,22 +77,20 @@ class PrimaryNotificationsHandler(MTEventHandler):
app.last_tid = tid
# Update cache
cache = app._cache
app._cache_lock_acquire()
try:
with app._cache_lock:
invalidate = app._cache.invalidate
loading = app._loading_oid
loading_get = app._loading.get
for oid, data in cache_dict.iteritems():
# Update ex-latest value in cache
invalidate(oid, tid)
if oid == loading:
app._loading_invalidated.append(tid)
loading = loading_get(oid)
if loading:
loading[1].append(tid)
if data is not None:
# Store in cache with no next_tid
cache.store(oid, data, tid, None)
if callback is not None:
callback(tid)
finally:
app._cache_lock_release()
def connectionClosed(self, conn):
app = self.app
......@@ -124,19 +119,17 @@ class PrimaryNotificationsHandler(MTEventHandler):
if app.ignore_invalidations:
return
app.last_tid = tid
app._cache_lock_acquire()
try:
with app._cache_lock:
invalidate = app._cache.invalidate
loading = app._loading_oid
loading_get = app._loading.get
for oid in oid_list:
invalidate(oid, tid)
if oid == loading:
app._loading_invalidated.append(tid)
loading = loading_get(oid)
if loading:
loading[1].append(tid)
db = app.getDB()
if db is not None:
db.invalidate(tid, oid_list)
finally:
app._cache_lock_release()
def notifyPartitionChanges(self, conn, ptid, cell_list):
if self.app.pt.filled():
......
......@@ -197,8 +197,7 @@ elif IF == 'trace-cache':
@defer
def profile(app):
app._cache_lock_acquire()
try:
with app._cache_lock:
cache = app._cache
if type(cache) is ClientCache:
app._cache = CacheTracer(cache, '%s-%s.neo-cache-trace' %
......@@ -206,5 +205,3 @@ elif IF == 'trace-cache':
app._cache.clear()
else:
app._cache = cache.close()
finally:
app._cache_lock_release()
......@@ -1072,8 +1072,7 @@ class NEOThreadedTest(NeoTestBase):
def run(self):
try:
apply(*self.__target)
self.__exc_info = None
self.__result = apply(*self.__target)
except:
self.__exc_info = sys.exc_info()
if self.__exc_info[0] is NEOThreadedTest.failureException:
......@@ -1081,7 +1080,10 @@ class NEOThreadedTest(NeoTestBase):
def join(self, timeout=None):
threading.Thread.join(self, timeout)
if not self.is_alive() and self.__exc_info:
if not self.is_alive():
try:
return self.__result
except AttributeError:
etype, value, tb = self.__exc_info
del self.__exc_info
raise etype, value, tb
......
......@@ -1009,7 +1009,7 @@ class Test(NEOThreadedTest):
x = r[''] = PCounter()
t.commit()
tid1 = x._p_serial
nonlocal_ = [0, 1]
nonlocal_ = [0, 0, 0]
l1 = threading.Lock(); l1.acquire()
l2 = threading.Lock(); l2.acquire()
def invalidateObjects(orig, *args):
......@@ -1019,12 +1019,26 @@ class Test(NEOThreadedTest):
nonlocal_[0] += 1
if nonlocal_[0] == 2:
l2.release()
def _cache_lock_release(orig):
orig()
if nonlocal_[1]:
nonlocal_[1] = 0
l1.release()
class CacheLock(object):
def __init__(self, client):
self._lock = client._cache_lock
def __enter__(self):
self._lock.acquire()
def __exit__(self, t, v, tb):
count = nonlocal_[1]
nonlocal_[1] = count + 1
self._lock.release()
if count == 0:
load_same.start()
l2.acquire()
elif count == 1:
load_other.start()
def _loadFromStorage(orig, *args):
count = nonlocal_[2]
nonlocal_[2] = count + 1
if not count:
l1.release()
return orig(*args)
with cluster.newClient() as client, \
Patch(client.notifications_handler,
invalidateObjects=invalidateObjects):
......@@ -1043,17 +1057,34 @@ class Test(NEOThreadedTest):
r._p_changed = 1
t.commit()
self.assertEqual(tid1, client.last_tid)
with Patch(client, _cache_lock_release=_cache_lock_release):
load_same = self.newPausedThread(client.load, x._p_oid)
load_other = self.newPausedThread(client.load, r._p_oid)
with Patch(client, _cache_lock=CacheLock(client)), \
Patch(client, _loadFromStorage=_loadFromStorage):
# 1. Just after having found nothing in cache, the worker
# thread asks the poll thread to get notified about
# invalidations for the loading oid.
# <context switch>
# <context switch> (l1)
# 2. Both invalidations are processed. -> last_tid=tid3
# <context switch>
# <context switch> (l2)
# 3. The worker thread loads before tid3+1.
# The poll thread notified [tid2], which must be ignored.
self.assertEqual((tid2, None), client.load(x._p_oid)[1:])
self.assertEqual(nonlocal_, [2, 0])
# In parallel, 2 other loads are done (both cache misses):
# - one for the same oid, which waits for first load to
# complete and in particular fill cache, in order to
# avoid asking the same data to the storage node
# - another for a different oid, which doesn't wait, as shown
# by the fact that it returns an old record (i.e. before any
# invalidation packet is processed)
loaded = client.load(x._p_oid)
self.assertEqual((tid2, None), loaded[1:])
self.assertEqual(loaded, load_same.join())
self.assertEqual((tid1, r._p_serial), load_other.join()[1:])
# To summary:
# - 3 concurrent loads starting with cache misses
# - 2 loads from storage
# - 1 load ending with a cache hit
self.assertEqual(nonlocal_, [2, 8, 2])
@with_cluster(storage_count=2, partitions=2)
def testReadVerifyingStorage(self, cluster):
......
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