[Python-checkins] python/dist/src/Objects intobject.c,2.82,2.83

2002年4月28日 09:57:37 -0700

Update of /cvsroot/python/python/dist/src/Objects
In directory usw-pr-cvs1:/tmp/cvs-serv7261/python/Objects
Modified Files:
	intobject.c 
Log Message:
Just added comments, and cleared some XXX questions, related to int
memory management.
Index: intobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/intobject.c,v
retrieving revision 2.82
retrieving revision 2.83
diff -C2 -d -r2.82 -r2.83
*** intobject.c	26 Apr 2002 00:53:34 -0000	2.82
--- intobject.c	28 Apr 2002 16:57:34 -0000	2.83
***************
*** 27,35 ****
 (Using odd pointers to represent integers would save much space
 but require extra checks for this special case throughout the code.)
! Since, a typical Python program spends much of its time allocating
 and deallocating integers, these operations should be very fast.
 Therefore we use a dedicated allocation scheme with a much lower
 overhead (in space and time) than straight malloc(): a simple
 dedicated free list, filled when necessary with memory from malloc().
 */
 
--- 27,42 ----
 (Using odd pointers to represent integers would save much space
 but require extra checks for this special case throughout the code.)
! Since a typical Python program spends much of its time allocating
 and deallocating integers, these operations should be very fast.
 Therefore we use a dedicated allocation scheme with a much lower
 overhead (in space and time) than straight malloc(): a simple
 dedicated free list, filled when necessary with memory from malloc().
+ 
+ block_list is a singly-linked list of all PyIntBlocks ever allocated,
+ linked via their next members. PyIntBlocks are never returned to the
+ system before shutdown (PyInt_Fini).
+ 
+ free_list is a singly-linked list of available PyIntObjects, linked
+ via abuse of their ob_type members.
 */
 
***************
*** 52,56 ****
 {
 	PyIntObject *p, *q;
! 	/* XXX Int blocks escape the object heap. Use PyObject_MALLOC ??? */
 	p = (PyIntObject *) PyMem_MALLOC(sizeof(PyIntBlock));
 	if (p == NULL)
--- 59,63 ----
 {
 	PyIntObject *p, *q;
! 	/* Python's object allocator isn't appropriate for large blocks. */
 	p = (PyIntObject *) PyMem_MALLOC(sizeof(PyIntBlock));
 	if (p == NULL)
***************
*** 58,61 ****
--- 65,70 ----
 	((PyIntBlock *)p)->next = block_list;
 	block_list = (PyIntBlock *)p;
+ 	/* Link the int objects together, from rear to front, then return
+ 	 the address of the last int object in the block. */
 	p = &((PyIntBlock *)p)->objects[0];
 	q = p + N_INTOBJECTS;
***************
*** 976,980 ****
 		}
 		else {
! 			PyMem_FREE(list); /* XXX PyObject_FREE ??? */
 			bf++;
 		}
--- 985,989 ----
 		}
 		else {
! 			PyMem_FREE(list);
 			bf++;
 		}