csp2: CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/lib/python3.8/multiprocessing/heap.py comparison

comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/lib/python3.8/multiprocessing/heap.py @ 69:33d812a61356

planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d

author	jpayne
date	Tue, 18 Mar 2025 17:55:14 -0400
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comparison

equal deleted inserted replaced

-:0e9998148a16
+:33d812a61356
+#
+# Module which supports allocation of memory from an mmap
+#
+# multiprocessing/heap.py
+#
+# Copyright (c) 2006-2008, R Oudkerk
+# Licensed to PSF under a Contributor Agreement.
+#
+import bisect
+from collections import defaultdict
+import mmap
+import os
+import sys
+import tempfile
+import threading
+from .context import reduction, assert_spawning
+from . import util
+__all__ = ['BufferWrapper']
+#
+# Inheritable class which wraps an mmap, and from which blocks can be allocated
+#
+if sys.platform == 'win32':
+import _winapi
+class Arena(object):
+"""
+A shared memory area backed by anonymous memory (Windows).
+"""
+_rand = tempfile._RandomNameSequence()
+def __init__(self, size):
+self.size = size
+for i in range(100):
+name = 'pym-%d-%s' % (os.getpid(), next(self._rand))
+buf = mmap.mmap(-1, size, tagname=name)
+if _winapi.GetLastError() == 0:
+break
+# We have reopened a preexisting mmap.
+buf.close()
+else:
+raise FileExistsError('Cannot find name for new mmap')
+self.name = name
+self.buffer = buf
+self._state = (self.size, self.name)
+def __getstate__(self):
+assert_spawning(self)
+return self._state
+def __setstate__(self, state):
+self.size, self.name = self._state = state
+# Reopen existing mmap
+self.buffer = mmap.mmap(-1, self.size, tagname=self.name)
+# XXX Temporarily preventing buildbot failures while determining
+# XXX the correct long-term fix. See issue 23060
+#assert _winapi.GetLastError() == _winapi.ERROR_ALREADY_EXISTS
+else:
+class Arena(object):
+"""
+A shared memory area backed by a temporary file (POSIX).
+"""
+if sys.platform == 'linux':
+_dir_candidates = ['/dev/shm']
+else:
+_dir_candidates = []
+def __init__(self, size, fd=-1):
+self.size = size
+self.fd = fd
+if fd == -1:
+# Arena is created anew (if fd != -1, it means we're coming
+# from rebuild_arena() below)
+self.fd, name = tempfile.mkstemp(
+prefix='pym-%d-'%os.getpid(),
+dir=self._choose_dir(size))
+os.unlink(name)
+util.Finalize(self, os.close, (self.fd,))
+os.ftruncate(self.fd, size)
+self.buffer = mmap.mmap(self.fd, self.size)
+def _choose_dir(self, size):
+# Choose a non-storage backed directory if possible,
+# to improve performance
+for d in self._dir_candidates:
+st = os.statvfs(d)
+if st.f_bavail * st.f_frsize >= size:  # enough free space?
+return d
+return util.get_temp_dir()
+def reduce_arena(a):
+if a.fd == -1:
+raise ValueError('Arena is unpicklable because '
+'forking was enabled when it was created')
+return rebuild_arena, (a.size, reduction.DupFd(a.fd))
+def rebuild_arena(size, dupfd):
+return Arena(size, dupfd.detach())
+reduction.register(Arena, reduce_arena)
+#
+# Class allowing allocation of chunks of memory from arenas
+#
+class Heap(object):
+# Minimum malloc() alignment
+_alignment = 8
+_DISCARD_FREE_SPACE_LARGER_THAN = 4 * 1024 ** 2  # 4 MB
+_DOUBLE_ARENA_SIZE_UNTIL = 4 * 1024 ** 2
+def __init__(self, size=mmap.PAGESIZE):
+self._lastpid = os.getpid()
+self._lock = threading.Lock()
+# Current arena allocation size
+self._size = size
+# A sorted list of available block sizes in arenas
+self._lengths = []
+# Free block management:
+# - map each block size to a list of `(Arena, start, stop)` blocks
+self._len_to_seq = {}
+# - map `(Arena, start)` tuple to the `(Arena, start, stop)` block
+#   starting at that offset
+self._start_to_block = {}
+# - map `(Arena, stop)` tuple to the `(Arena, start, stop)` block
+#   ending at that offset
+self._stop_to_block = {}
+# Map arenas to their `(Arena, start, stop)` blocks in use
+self._allocated_blocks = defaultdict(set)
+self._arenas = []
+# List of pending blocks to free - see comment in free() below
+self._pending_free_blocks = []
+# Statistics
+self._n_mallocs = 0
+self._n_frees = 0
+@staticmethod
+def _roundup(n, alignment):
+# alignment must be a power of 2
+mask = alignment - 1
+return (n + mask) & ~mask
+def _new_arena(self, size):
+# Create a new arena with at least the given *size*
+length = self._roundup(max(self._size, size), mmap.PAGESIZE)
+# We carve larger and larger arenas, for efficiency, until we
+# reach a large-ish size (roughly L3 cache-sized)
+if self._size < self._DOUBLE_ARENA_SIZE_UNTIL:
+self._size *= 2
+util.info('allocating a new mmap of length %d', length)
+arena = Arena(length)
+self._arenas.append(arena)
+return (arena, 0, length)
+def _discard_arena(self, arena):
+# Possibly delete the given (unused) arena
+length = arena.size
+# Reusing an existing arena is faster than creating a new one, so
+# we only reclaim space if it's large enough.
+if length < self._DISCARD_FREE_SPACE_LARGER_THAN:
+return
+blocks = self._allocated_blocks.pop(arena)
+assert not blocks
+del self._start_to_block[(arena, 0)]
+del self._stop_to_block[(arena, length)]
+self._arenas.remove(arena)
+seq = self._len_to_seq[length]
+seq.remove((arena, 0, length))
+if not seq:
+del self._len_to_seq[length]
+self._lengths.remove(length)
+def _malloc(self, size):
+# returns a large enough block -- it might be much larger
+i = bisect.bisect_left(self._lengths, size)
+if i == len(self._lengths):
+return self._new_arena(size)
+else:
+length = self._lengths[i]
+seq = self._len_to_seq[length]
+block = seq.pop()
+if not seq:
+del self._len_to_seq[length], self._lengths[i]
+(arena, start, stop) = block
+del self._start_to_block[(arena, start)]
+del self._stop_to_block[(arena, stop)]
+return block
+def _add_free_block(self, block):
+# make block available and try to merge with its neighbours in the arena
+(arena, start, stop) = block
+try:
+prev_block = self._stop_to_block[(arena, start)]
+except KeyError:
+pass
+else:
+start, _ = self._absorb(prev_block)
+try:
+next_block = self._start_to_block[(arena, stop)]
+except KeyError:
+pass
+else:
+_, stop = self._absorb(next_block)
+block = (arena, start, stop)
+length = stop - start
+try:
+self._len_to_seq[length].append(block)
+except KeyError:
+self._len_to_seq[length] = [block]
+bisect.insort(self._lengths, length)
+self._start_to_block[(arena, start)] = block
+self._stop_to_block[(arena, stop)] = block
+def _absorb(self, block):
+# deregister this block so it can be merged with a neighbour
+(arena, start, stop) = block
+del self._start_to_block[(arena, start)]
+del self._stop_to_block[(arena, stop)]
+length = stop - start
+seq = self._len_to_seq[length]
+seq.remove(block)
+if not seq:
+del self._len_to_seq[length]
+self._lengths.remove(length)
+return start, stop
+def _remove_allocated_block(self, block):
+arena, start, stop = block
+blocks = self._allocated_blocks[arena]
+blocks.remove((start, stop))
+if not blocks:
+# Arena is entirely free, discard it from this process
+self._discard_arena(arena)
+def _free_pending_blocks(self):
+# Free all the blocks in the pending list - called with the lock held.
+while True:
+try:
+block = self._pending_free_blocks.pop()
+except IndexError:
+break
+self._add_free_block(block)
+self._remove_allocated_block(block)
+def free(self, block):
+# free a block returned by malloc()
+# Since free() can be called asynchronously by the GC, it could happen
+# that it's called while self._lock is held: in that case,
+# self._lock.acquire() would deadlock (issue #12352). To avoid that, a
+# trylock is used instead, and if the lock can't be acquired
+# immediately, the block is added to a list of blocks to be freed
+# synchronously sometimes later from malloc() or free(), by calling
+# _free_pending_blocks() (appending and retrieving from a list is not
+# strictly thread-safe but under CPython it's atomic thanks to the GIL).
+if os.getpid() != self._lastpid:
+raise ValueError(
+"My pid ({0:n}) is not last pid {1:n}".format(
+os.getpid(),self._lastpid))
+if not self._lock.acquire(False):
+# can't acquire the lock right now, add the block to the list of
+# pending blocks to free
+self._pending_free_blocks.append(block)
+else:
+# we hold the lock
+try:
+self._n_frees += 1
+self._free_pending_blocks()
+self._add_free_block(block)
+self._remove_allocated_block(block)
+finally:
+self._lock.release()
+def malloc(self, size):
+# return a block of right size (possibly rounded up)
+if size < 0:
+raise ValueError("Size {0:n} out of range".format(size))
+if sys.maxsize <= size:
+raise OverflowError("Size {0:n} too large".format(size))
+if os.getpid() != self._lastpid:
+self.__init__()                     # reinitialize after fork
+with self._lock:
+self._n_mallocs += 1
+# allow pending blocks to be marked available
+self._free_pending_blocks()
+size = self._roundup(max(size, 1), self._alignment)
+(arena, start, stop) = self._malloc(size)
+real_stop = start + size
+if real_stop < stop:
+# if the returned block is larger than necessary, mark
+# the remainder available
+self._add_free_block((arena, real_stop, stop))
+self._allocated_blocks[arena].add((start, real_stop))
+return (arena, start, real_stop)
+#
+# Class wrapping a block allocated out of a Heap -- can be inherited by child process
+#
+class BufferWrapper(object):
+_heap = Heap()
+def __init__(self, size):
+if size < 0:
+raise ValueError("Size {0:n} out of range".format(size))
+if sys.maxsize <= size:
+raise OverflowError("Size {0:n} too large".format(size))
+block = BufferWrapper._heap.malloc(size)
+self._state = (block, size)
+util.Finalize(self, BufferWrapper._heap.free, args=(block,))
+def create_memoryview(self):
+(arena, start, stop), size = self._state
+return memoryview(arena.buffer)[start:start+size]

Mercurial > repos > rliterman > csp2

comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/lib/python3.8/multiprocessing/heap.py @ 69:33d812a61356