import collections
import datetime
import hashlib
+import errno
import io
import logging
import math
import resource
from . import timer
import urllib.parse
+import traceback
if sys.version_info >= (3, 0):
from io import BytesIO
if self._max_slots == 0:
if self._disk_cache:
- # default set max slots to half of maximum file handles
+ # default max slots to half of maximum file handles
+ # NOFILE typically defaults to 1024 on Linux so this
+ # will be 512 slots.
self._max_slots = resource.getrlimit(resource.RLIMIT_NOFILE)[0] / 2
else:
- self._max_slots = 1024
+ # RAM cache slots
+ self._max_slots = 512
if self.cache_max == 0:
if self._disk_cache:
fs = os.statvfs(self._disk_cache_dir)
- avail = (fs.f_bavail * fs.f_bsize) / 2
- # Half the available space or max_slots * 64 MiB
- self.cache_max = min(avail, (self._max_slots * 64 * 1024 * 1024))
+ # Calculation of available space incorporates existing cache usage
+ existing_usage = arvados.diskcache.DiskCacheSlot.cache_usage(self._disk_cache_dir)
+ avail = (fs.f_bavail * fs.f_bsize + existing_usage) / 4
+ maxdisk = int((fs.f_blocks * fs.f_bsize) * 0.10)
+ # pick smallest of:
+ # 10% of total disk size
+ # 25% of available space
+ # max_slots * 64 MiB
+ self.cache_max = min(min(maxdisk, avail), (self._max_slots * 64 * 1024 * 1024))
else:
- # 256 GiB in RAM
+ # 256 MiB in RAM
self.cache_max = (256 * 1024 * 1024)
self.cache_max = max(self.cache_max, 64 * 1024 * 1024)
+ if self._disk_cache:
+ self._cache = arvados.diskcache.DiskCacheSlot.init_cache(self._disk_cache_dir, self._max_slots)
+ self.cap_cache()
+
+
class CacheSlot(object):
__slots__ = ("locator", "ready", "content")
return len(self.content)
def evict(self):
- pass
+ return True
def cap_cache(self):
'''Cap the cache size to self.cache_max'''
sm = sum([slot.size() for slot in self._cache])
while len(self._cache) > 0 and (sm > self.cache_max or len(self._cache) > self._max_slots):
for i in range(len(self._cache)-1, -1, -1):
+ # start from the back, find a slot that is a candidate to evict
if self._cache[i].ready.is_set():
- self._cache[i].evict()
+ sz = self._cache[i].size()
+
+ # If evict returns false it means the
+ # underlying disk cache couldn't lock the file
+ # for deletion because another process was using
+ # it. Don't count it as reducing the amount
+ # of data in the cache, find something else to
+ # throw out.
+ if self._cache[i].evict():
+ sm -= sz
+
+ # either way we forget about it. either the
+ # other process will delete it, or if we need
+ # it again and it is still there, we'll find
+ # it on disk.
del self._cache[i]
break
- sm = sum([slot.size() for slot in self._cache])
def _get(self, locator):
# Test if the locator is already in the cache
self._cache.insert(0, n)
return n, True
+ def set(self, slot, blob):
+ try:
+ slot.set(blob)
+ return
+ except OSError as e:
+ if e.errno == errno.ENOMEM:
+ # Reduce max slots to current - 4, cap cache and retry
+ with self._cache_lock:
+ self._max_slots = max(4, len(self._cache) - 4)
+ elif e.errno == errno.ENOSPC:
+ # Reduce disk max space to current - 256 MiB, cap cache and retry
+ with self._cache_lock:
+ sm = sum([st.size() for st in self._cache])
+ self.cache_max = max((256 * 1024 * 1024), sm - (256 * 1024 * 1024))
+ elif e.errno == errno.ENODEV:
+ _logger.error("Unable to use disk cache: The underlying filesystem does not support memory mapping.")
+ except Exception as e:
+ pass
+ finally:
+ # Check if we should evict things from the cache. Either
+ # because we added a new thing or there was an error and
+ # we possibly adjusted the limits down, so we might need
+ # to push something out.
+ self.cap_cache()
+
+ try:
+ # Only gets here if there was an error the first time. The
+ # exception handler adjusts limits downward in some cases
+ # to free up resources, which would make the operation
+ # succeed.
+ slot.set(blob)
+ self.cap_cache()
+ except Exception as e:
+ # It failed again. Give up.
+ raise arvados.errors.KeepCacheError("Unable to save block %s to disk cache: %s" % (slot.locator, e))
+ finally:
+ # Set the notice that that we are done with the cache
+ # slot one way or another.
+ slot.ready.set()
+
+
class Counter(object):
def __init__(self, v=0):
self._lk = threading.Lock()
return blob
finally:
if slot is not None:
- slot.set(blob)
- self.block_cache.cap_cache()
+ self.block_cache.set(slot, blob)
# Q: Including 403 is necessary for the Keep tests to continue
# passing, but maybe they should expect KeepReadError instead?
projects / arvados.git / blobdiff