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Tim Peters1221c0a2002-03-23 00:20:15 +00001#include "Python.h"
2
3#ifdef WITH_PYMALLOC
4
Neil Schemenauera35c6882001-02-27 04:45:05 +00005/* An object allocator for Python.
6
7 Here is an introduction to the layers of the Python memory architecture,
8 showing where the object allocator is actually used (layer +2), It is
9 called for every object allocation and deallocation (PyObject_New/Del),
10 unless the object-specific allocators implement a proprietary allocation
11 scheme (ex.: ints use a simple free list). This is also the place where
12 the cyclic garbage collector operates selectively on container objects.
13
14
15 Object-specific allocators
16 _____ ______ ______ ________
17 [ int ] [ dict ] [ list ] ... [ string ] Python core |
18+3 | <----- Object-specific memory -----> | <-- Non-object memory --> |
19 _______________________________ | |
20 [ Python's object allocator ] | |
21+2 | ####### Object memory ####### | <------ Internal buffers ------> |
22 ______________________________________________________________ |
23 [ Python's raw memory allocator (PyMem_ API) ] |
24+1 | <----- Python memory (under PyMem manager's control) ------> | |
25 __________________________________________________________________
26 [ Underlying general-purpose allocator (ex: C library malloc) ]
27 0 | <------ Virtual memory allocated for the python process -------> |
28
29 =========================================================================
30 _______________________________________________________________________
31 [ OS-specific Virtual Memory Manager (VMM) ]
32-1 | <--- Kernel dynamic storage allocation & management (page-based) ---> |
33 __________________________________ __________________________________
34 [ ] [ ]
35-2 | <-- Physical memory: ROM/RAM --> | | <-- Secondary storage (swap) --> |
36
37*/
38/*==========================================================================*/
39
40/* A fast, special-purpose memory allocator for small blocks, to be used
41 on top of a general-purpose malloc -- heavily based on previous art. */
42
43/* Vladimir Marangozov -- August 2000 */
44
45/*
46 * "Memory management is where the rubber meets the road -- if we do the wrong
47 * thing at any level, the results will not be good. And if we don't make the
48 * levels work well together, we are in serious trouble." (1)
49 *
50 * (1) Paul R. Wilson, Mark S. Johnstone, Michael Neely, and David Boles,
51 * "Dynamic Storage Allocation: A Survey and Critical Review",
52 * in Proc. 1995 Int'l. Workshop on Memory Management, September 1995.
53 */
54
55/* #undef WITH_MEMORY_LIMITS */ /* disable mem limit checks */
Neil Schemenauera35c6882001-02-27 04:45:05 +000056
57/*==========================================================================*/
58
59/*
Neil Schemenauera35c6882001-02-27 04:45:05 +000060 * Allocation strategy abstract:
61 *
62 * For small requests, the allocator sub-allocates <Big> blocks of memory.
63 * Requests greater than 256 bytes are routed to the system's allocator.
Tim Petersce7fb9b2002-03-23 00:28:57 +000064 *
Neil Schemenauera35c6882001-02-27 04:45:05 +000065 * Small requests are grouped in size classes spaced 8 bytes apart, due
66 * to the required valid alignment of the returned address. Requests of
67 * a particular size are serviced from memory pools of 4K (one VMM page).
68 * Pools are fragmented on demand and contain free lists of blocks of one
69 * particular size class. In other words, there is a fixed-size allocator
70 * for each size class. Free pools are shared by the different allocators
71 * thus minimizing the space reserved for a particular size class.
72 *
73 * This allocation strategy is a variant of what is known as "simple
74 * segregated storage based on array of free lists". The main drawback of
75 * simple segregated storage is that we might end up with lot of reserved
76 * memory for the different free lists, which degenerate in time. To avoid
77 * this, we partition each free list in pools and we share dynamically the
78 * reserved space between all free lists. This technique is quite efficient
79 * for memory intensive programs which allocate mainly small-sized blocks.
80 *
81 * For small requests we have the following table:
82 *
83 * Request in bytes Size of allocated block Size class idx
84 * ----------------------------------------------------------------
85 * 1-8 8 0
86 * 9-16 16 1
87 * 17-24 24 2
88 * 25-32 32 3
89 * 33-40 40 4
90 * 41-48 48 5
91 * 49-56 56 6
92 * 57-64 64 7
93 * 65-72 72 8
94 * ... ... ...
95 * 241-248 248 30
96 * 249-256 256 31
Tim Petersce7fb9b2002-03-23 00:28:57 +000097 *
Neil Schemenauera35c6882001-02-27 04:45:05 +000098 * 0, 257 and up: routed to the underlying allocator.
99 */
100
101/*==========================================================================*/
102
103/*
104 * -- Main tunable settings section --
105 */
106
107/*
108 * Alignment of addresses returned to the user. 8-bytes alignment works
109 * on most current architectures (with 32-bit or 64-bit address busses).
110 * The alignment value is also used for grouping small requests in size
111 * classes spaced ALIGNMENT bytes apart.
112 *
113 * You shouldn't change this unless you know what you are doing.
114 */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000115#define ALIGNMENT 8 /* must be 2^N */
116#define ALIGNMENT_SHIFT 3
117#define ALIGNMENT_MASK (ALIGNMENT - 1)
118
119/*
120 * Max size threshold below which malloc requests are considered to be
121 * small enough in order to use preallocated memory pools. You can tune
122 * this value according to your application behaviour and memory needs.
123 *
124 * The following invariants must hold:
125 * 1) ALIGNMENT <= SMALL_REQUEST_THRESHOLD <= 256
Tim Petersd97a1c02002-03-30 06:09:22 +0000126 * 2) SMALL_REQUEST_THRESHOLD is evenly divisible by ALIGNMENT
Neil Schemenauera35c6882001-02-27 04:45:05 +0000127 *
128 * Although not required, for better performance and space efficiency,
129 * it is recommended that SMALL_REQUEST_THRESHOLD is set to a power of 2.
130 */
Tim Petersd97a1c02002-03-30 06:09:22 +0000131#define SMALL_REQUEST_THRESHOLD 256
Neil Schemenauera35c6882001-02-27 04:45:05 +0000132#define NB_SMALL_SIZE_CLASSES (SMALL_REQUEST_THRESHOLD / ALIGNMENT)
133
134/*
135 * The system's VMM page size can be obtained on most unices with a
136 * getpagesize() call or deduced from various header files. To make
137 * things simpler, we assume that it is 4K, which is OK for most systems.
138 * It is probably better if this is the native page size, but it doesn't
139 * have to be.
140 */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000141#define SYSTEM_PAGE_SIZE (4 * 1024)
142#define SYSTEM_PAGE_SIZE_MASK (SYSTEM_PAGE_SIZE - 1)
143
144/*
145 * Maximum amount of memory managed by the allocator for small requests.
146 */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000147#ifdef WITH_MEMORY_LIMITS
148#ifndef SMALL_MEMORY_LIMIT
149#define SMALL_MEMORY_LIMIT (64 * 1024 * 1024) /* 64 MB -- more? */
150#endif
151#endif
152
153/*
154 * The allocator sub-allocates <Big> blocks of memory (called arenas) aligned
155 * on a page boundary. This is a reserved virtual address space for the
156 * current process (obtained through a malloc call). In no way this means
157 * that the memory arenas will be used entirely. A malloc(<Big>) is usually
158 * an address range reservation for <Big> bytes, unless all pages within this
159 * space are referenced subsequently. So malloc'ing big blocks and not using
160 * them does not mean "wasting memory". It's an addressable range wastage...
161 *
162 * Therefore, allocating arenas with malloc is not optimal, because there is
163 * some address space wastage, but this is the most portable way to request
Tim Petersd97a1c02002-03-30 06:09:22 +0000164 * memory from the system across various platforms.
Neil Schemenauera35c6882001-02-27 04:45:05 +0000165 */
Tim Peters3c83df22002-03-30 07:04:41 +0000166#define ARENA_SIZE (256 << 10) /* 256KB */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000167
168#ifdef WITH_MEMORY_LIMITS
169#define MAX_ARENAS (SMALL_MEMORY_LIMIT / ARENA_SIZE)
170#endif
171
172/*
173 * Size of the pools used for small blocks. Should be a power of 2,
174 * between 1K and SYSTEM_PAGE_SIZE, that is: 1k, 2k, 4k, eventually 8k.
175 */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000176#define POOL_SIZE SYSTEM_PAGE_SIZE /* must be 2^N */
177#define POOL_SIZE_MASK SYSTEM_PAGE_SIZE_MASK
Neil Schemenauera35c6882001-02-27 04:45:05 +0000178
179/*
180 * -- End of tunable settings section --
181 */
182
183/*==========================================================================*/
184
185/*
186 * Locking
187 *
188 * To reduce lock contention, it would probably be better to refine the
189 * crude function locking with per size class locking. I'm not positive
190 * however, whether it's worth switching to such locking policy because
191 * of the performance penalty it might introduce.
192 *
193 * The following macros describe the simplest (should also be the fastest)
194 * lock object on a particular platform and the init/fini/lock/unlock
195 * operations on it. The locks defined here are not expected to be recursive
196 * because it is assumed that they will always be called in the order:
197 * INIT, [LOCK, UNLOCK]*, FINI.
198 */
199
200/*
201 * Python's threads are serialized, so object malloc locking is disabled.
202 */
203#define SIMPLELOCK_DECL(lock) /* simple lock declaration */
204#define SIMPLELOCK_INIT(lock) /* allocate (if needed) and initialize */
205#define SIMPLELOCK_FINI(lock) /* free/destroy an existing lock */
206#define SIMPLELOCK_LOCK(lock) /* acquire released lock */
207#define SIMPLELOCK_UNLOCK(lock) /* release acquired lock */
208
209/*
210 * Basic types
211 * I don't care if these are defined in <sys/types.h> or elsewhere. Axiom.
212 */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000213#undef uchar
214#define uchar unsigned char /* assuming == 8 bits */
215
Neil Schemenauera35c6882001-02-27 04:45:05 +0000216#undef uint
217#define uint unsigned int /* assuming >= 16 bits */
218
219#undef ulong
220#define ulong unsigned long /* assuming >= 32 bits */
221
Tim Petersd97a1c02002-03-30 06:09:22 +0000222#undef uptr
223#define uptr Py_uintptr_t
224
Neil Schemenauera35c6882001-02-27 04:45:05 +0000225/* When you say memory, my mind reasons in terms of (pointers to) blocks */
226typedef uchar block;
227
228/* Pool for small blocks */
229struct pool_header {
Tim Petersb2336522001-03-11 18:36:13 +0000230 union { block *_padding;
Neil Schemenauera35c6882001-02-27 04:45:05 +0000231 uint count; } ref; /* number of allocated blocks */
232 block *freeblock; /* pool's free list head */
233 struct pool_header *nextpool; /* next pool of this size class */
234 struct pool_header *prevpool; /* previous pool "" */
Tim Peters1d99af82002-03-30 10:35:09 +0000235 uint arenaindex; /* index into arenas of base adr */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000236 uint szidx; /* block size class index */
237 uint capacity; /* pool capacity in # of blocks */
238};
239
240typedef struct pool_header *poolp;
241
242#undef ROUNDUP
243#define ROUNDUP(x) (((x) + ALIGNMENT_MASK) & ~ALIGNMENT_MASK)
244#define POOL_OVERHEAD ROUNDUP(sizeof(struct pool_header))
245
246#define DUMMY_SIZE_IDX 0xffff /* size class of newly cached pools */
247
Tim Petersd97a1c02002-03-30 06:09:22 +0000248/* Round pointer P down to the closest pool-aligned address <= P, as a poolp */
249#define POOL_ADDR(P) \
250 ((poolp)((uptr)(P) & ~(uptr)POOL_SIZE_MASK))
251
Neil Schemenauera35c6882001-02-27 04:45:05 +0000252/*==========================================================================*/
253
254/*
255 * This malloc lock
256 */
Tim Petersb2336522001-03-11 18:36:13 +0000257SIMPLELOCK_DECL(_malloc_lock);
258#define LOCK() SIMPLELOCK_LOCK(_malloc_lock)
259#define UNLOCK() SIMPLELOCK_UNLOCK(_malloc_lock)
260#define LOCK_INIT() SIMPLELOCK_INIT(_malloc_lock)
261#define LOCK_FINI() SIMPLELOCK_FINI(_malloc_lock)
Neil Schemenauera35c6882001-02-27 04:45:05 +0000262
263/*
264 * Pool table -- doubly linked lists of partially used pools
265 */
266#define PTA(x) ((poolp )((uchar *)&(usedpools[2*(x)]) - 2*sizeof(block *)))
267#define PT(x) PTA(x), PTA(x)
268
269static poolp usedpools[2 * ((NB_SMALL_SIZE_CLASSES + 7) / 8) * 8] = {
270 PT(0), PT(1), PT(2), PT(3), PT(4), PT(5), PT(6), PT(7)
271#if NB_SMALL_SIZE_CLASSES > 8
272 , PT(8), PT(9), PT(10), PT(11), PT(12), PT(13), PT(14), PT(15)
273#if NB_SMALL_SIZE_CLASSES > 16
274 , PT(16), PT(17), PT(18), PT(19), PT(20), PT(21), PT(22), PT(23)
275#if NB_SMALL_SIZE_CLASSES > 24
276 , PT(24), PT(25), PT(26), PT(27), PT(28), PT(29), PT(30), PT(31)
277#if NB_SMALL_SIZE_CLASSES > 32
278 , PT(32), PT(33), PT(34), PT(35), PT(36), PT(37), PT(38), PT(39)
279#if NB_SMALL_SIZE_CLASSES > 40
280 , PT(40), PT(41), PT(42), PT(43), PT(44), PT(45), PT(46), PT(47)
281#if NB_SMALL_SIZE_CLASSES > 48
282 , PT(48), PT(49), PT(50), PT(51), PT(52), PT(53), PT(54), PT(55)
283#if NB_SMALL_SIZE_CLASSES > 56
284 , PT(56), PT(57), PT(58), PT(59), PT(60), PT(61), PT(62), PT(63)
285#endif /* NB_SMALL_SIZE_CLASSES > 56 */
286#endif /* NB_SMALL_SIZE_CLASSES > 48 */
287#endif /* NB_SMALL_SIZE_CLASSES > 40 */
288#endif /* NB_SMALL_SIZE_CLASSES > 32 */
289#endif /* NB_SMALL_SIZE_CLASSES > 24 */
290#endif /* NB_SMALL_SIZE_CLASSES > 16 */
291#endif /* NB_SMALL_SIZE_CLASSES > 8 */
292};
293
294/*
295 * Free (cached) pools
296 */
297static poolp freepools = NULL; /* free list for cached pools */
298
Tim Petersd97a1c02002-03-30 06:09:22 +0000299/*==========================================================================*/
300/* Arena management. */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000301
Tim Petersd97a1c02002-03-30 06:09:22 +0000302/* arenas is a vector of arena base addresses, in order of allocation time.
303 * arenas currently contains narenas entries, and has space allocated
304 * for at most maxarenas entries.
305 *
306 * CAUTION: See the long comment block about thread safety in new_arena():
307 * the code currently relies in deep ways on that this vector only grows,
308 * and only grows by appending at the end. For now we never return an arena
309 * to the OS.
310 */
311static uptr *arenas = NULL;
Tim Peters1d99af82002-03-30 10:35:09 +0000312static uint narenas = 0;
313static uint maxarenas = 0;
Tim Petersd97a1c02002-03-30 06:09:22 +0000314
Tim Peters3c83df22002-03-30 07:04:41 +0000315/* Number of pools still available to be allocated in the current arena. */
316static uint nfreepools = 0;
Tim Petersd97a1c02002-03-30 06:09:22 +0000317
Tim Peters3c83df22002-03-30 07:04:41 +0000318/* Free space start address in current arena. This is pool-aligned. */
Tim Petersd97a1c02002-03-30 06:09:22 +0000319static block *arenabase = NULL;
320
321#if 0
322static ulong wasmine = 0;
323static ulong wasntmine = 0;
324
325static void
326dumpem(void *ptr)
327{
328 if (ptr)
329 printf("inserted new arena at %08x\n", ptr);
Tim Peters1d99af82002-03-30 10:35:09 +0000330 printf("# arenas %u\n", narenas);
Tim Petersd97a1c02002-03-30 06:09:22 +0000331 printf("was mine %lu wasn't mine %lu\n", wasmine, wasntmine);
332}
333#define INCMINE ++wasmine
334#define INCTHEIRS ++wasntmine
335
336#else
337#define dumpem(ptr)
338#define INCMINE
339#define INCTHEIRS
340#endif
341
342/* Allocate a new arena and return its base address. If we run out of
343 * memory, return NULL.
344 */
345static block *
346new_arena(void)
347{
Tim Peters3c83df22002-03-30 07:04:41 +0000348 uint excess; /* number of bytes above pool alignment */
349 block *bp = (block *)PyMem_MALLOC(ARENA_SIZE);
Tim Petersd97a1c02002-03-30 06:09:22 +0000350 if (bp == NULL)
351 return NULL;
352
Tim Peters3c83df22002-03-30 07:04:41 +0000353 /* arenabase <- first pool-aligned address in the arena
354 nfreepools <- number of whole pools that fit after alignment */
355 arenabase = bp;
356 nfreepools = ARENA_SIZE / POOL_SIZE;
357 excess = (uint)bp & POOL_SIZE_MASK;
358 if (excess != 0) {
359 --nfreepools;
360 arenabase += POOL_SIZE - excess;
361 }
Tim Petersd97a1c02002-03-30 06:09:22 +0000362
363 /* Make room for a new entry in the arenas vector. */
364 if (arenas == NULL) {
365 arenas = (uptr *)PyMem_MALLOC(16 * sizeof(*arenas));
366 if (arenas == NULL)
367 goto error;
368 maxarenas = 16;
369 narenas = 0;
370 }
371 else if (narenas == maxarenas) {
372 /* Grow arenas. Don't use realloc: if this fails, we
373 * don't want to lose the base addresses we already have.
374 * Exceedingly subtle: Someone may be calling the pymalloc
375 * free via PyMem_{DEL, Del, FREE, Free} without holding the
376 *.GIL. Someone else may simultaneously be calling the
377 * pymalloc malloc while holding the GIL via, e.g.,
378 * PyObject_New. Now the pymalloc free may index into arenas
379 * for an address check, while the pymalloc malloc calls
380 * new_arena and we end up here to grow a new arena *and*
381 * grow the arenas vector. If the value for arenas pymalloc
382 * free picks up "vanishes" during this resize, anything may
383 * happen, and it would be an incredibly rare bug. Therefore
384 * the code here takes great pains to make sure that, at every
385 * moment, arenas always points to an intact vector of
386 * addresses. It doesn't matter whether arenas points to a
387 * wholly up-to-date vector when pymalloc free checks it in
388 * this case, because the only legal (and that even this is
389 * legal is debatable) way to call PyMem_{Del, etc} while not
390 * holding the GIL is if the memory being released is not
391 * object memory, i.e. if the address check in pymalloc free
392 * is supposed to fail. Having an incomplete vector can't
393 * make a supposed-to-fail case succeed by mistake (it could
394 * only make a supposed-to-succeed case fail by mistake).
395 * Read the above 50 times before changing anything in this
396 * block.
Tim Peters12300682002-03-30 06:20:23 +0000397 * XXX Fudge. This is still vulnerable: there's nothing
398 * XXX to stop the bad-guy thread from picking up the
399 * XXX current value of arenas, but not indexing off of it
400 * XXX until after the PyMem_FREE(oldarenas) below completes.
Tim Petersd97a1c02002-03-30 06:09:22 +0000401 */
402 uptr *oldarenas;
Tim Peters1d99af82002-03-30 10:35:09 +0000403 uptr *p;
404 uint newmax = maxarenas + (maxarenas >> 1);
405
406 if (newmax <= maxarenas) /* overflow */
407 goto error;
408 p = (uptr *)PyMem_MALLOC(newmax * sizeof(*arenas));
Tim Petersd97a1c02002-03-30 06:09:22 +0000409 if (p == NULL)
410 goto error;
411 memcpy(p, arenas, narenas * sizeof(*arenas));
412 oldarenas = arenas;
413 arenas = p;
414 PyMem_FREE(oldarenas);
415 maxarenas = newmax;
416 }
417
418 /* Append the new arena address to arenas. */
419 assert(narenas < maxarenas);
420 arenas[narenas] = (uptr)bp;
Tim Peters1d99af82002-03-30 10:35:09 +0000421 ++narenas; /* can't overflow, since narenas < maxarenas before */
Tim Petersd97a1c02002-03-30 06:09:22 +0000422 dumpem(bp);
423 return bp;
424
425error:
426 PyMem_FREE(bp);
427 return NULL;
428}
429
430/* Return true if and only if P is an address that was allocated by
431 * pymalloc. I must be the index into arenas that the address claims
432 * to come from.
433 * Tricky: Letting B be the arena base address in arenas[I], P belongs to the
434 * arena if and only if
Tim Peters3c83df22002-03-30 07:04:41 +0000435 * B <= P < B + ARENA_SIZE
Tim Petersd97a1c02002-03-30 06:09:22 +0000436 * Subtracting B throughout, this is true iff
Tim Peters3c83df22002-03-30 07:04:41 +0000437 * 0 <= P-B < ARENA_SIZE
Tim Petersd97a1c02002-03-30 06:09:22 +0000438 * By using unsigned arithmetic, the "0 <=" half of the test can be skipped.
439 */
440#define ADDRESS_IN_RANGE(P, I) \
Tim Peters3c83df22002-03-30 07:04:41 +0000441 ((I) < narenas && (uptr)(P) - arenas[I] < (uptr)ARENA_SIZE)
Neil Schemenauera35c6882001-02-27 04:45:05 +0000442/*==========================================================================*/
443
444/* malloc */
445
446/*
447 * The basic blocks are ordered by decreasing execution frequency,
448 * which minimizes the number of jumps in the most common cases,
449 * improves branching prediction and instruction scheduling (small
450 * block allocations typically result in a couple of instructions).
451 * Unless the optimizer reorders everything, being too smart...
452 */
453
454void *
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000455_PyMalloc_Malloc(size_t nbytes)
Neil Schemenauera35c6882001-02-27 04:45:05 +0000456{
457 block *bp;
458 poolp pool;
459 poolp next;
460 uint size;
461
Neil Schemenauera35c6882001-02-27 04:45:05 +0000462 /*
463 * This implicitly redirects malloc(0)
464 */
465 if ((nbytes - 1) < SMALL_REQUEST_THRESHOLD) {
466 LOCK();
467 /*
468 * Most frequent paths first
469 */
470 size = (uint )(nbytes - 1) >> ALIGNMENT_SHIFT;
471 pool = usedpools[size + size];
472 if (pool != pool->nextpool) {
473 /*
474 * There is a used pool for this size class.
475 * Pick up the head block of its free list.
476 */
477 ++pool->ref.count;
478 bp = pool->freeblock;
479 if ((pool->freeblock = *(block **)bp) != NULL) {
480 UNLOCK();
481 return (void *)bp;
482 }
483 /*
484 * Reached the end of the free list, try to extend it
485 */
486 if (pool->ref.count < pool->capacity) {
487 /*
488 * There is room for another block
489 */
490 size++;
491 size <<= ALIGNMENT_SHIFT; /* block size */
492 pool->freeblock = (block *)pool + \
493 POOL_OVERHEAD + \
494 pool->ref.count * size;
495 *(block **)(pool->freeblock) = NULL;
496 UNLOCK();
497 return (void *)bp;
498 }
499 /*
500 * Pool is full, unlink from used pools
501 */
502 next = pool->nextpool;
503 pool = pool->prevpool;
504 next->prevpool = pool;
505 pool->nextpool = next;
506 UNLOCK();
507 return (void *)bp;
508 }
509 /*
510 * Try to get a cached free pool
511 */
512 pool = freepools;
513 if (pool != NULL) {
514 /*
515 * Unlink from cached pools
516 */
517 freepools = pool->nextpool;
518 init_pool:
519 /*
520 * Frontlink to used pools
521 */
522 next = usedpools[size + size]; /* == prev */
523 pool->nextpool = next;
524 pool->prevpool = next;
525 next->nextpool = pool;
526 next->prevpool = pool;
527 pool->ref.count = 1;
528 if (pool->szidx == size) {
529 /*
530 * Luckily, this pool last contained blocks
531 * of the same size class, so its header
532 * and free list are already initialized.
533 */
534 bp = pool->freeblock;
535 pool->freeblock = *(block **)bp;
536 UNLOCK();
537 return (void *)bp;
538 }
539 /*
540 * Initialize the pool header and free list
541 * then return the first block.
542 */
543 pool->szidx = size;
544 size++;
545 size <<= ALIGNMENT_SHIFT; /* block size */
546 bp = (block *)pool + POOL_OVERHEAD;
547 pool->freeblock = bp + size;
548 *(block **)(pool->freeblock) = NULL;
549 pool->capacity = (POOL_SIZE - POOL_OVERHEAD) / size;
550 UNLOCK();
551 return (void *)bp;
552 }
553 /*
554 * Allocate new pool
555 */
Tim Peters3c83df22002-03-30 07:04:41 +0000556 if (nfreepools) {
Neil Schemenauera35c6882001-02-27 04:45:05 +0000557 commit_pool:
Tim Peters3c83df22002-03-30 07:04:41 +0000558 --nfreepools;
559 pool = (poolp)arenabase;
Neil Schemenauera35c6882001-02-27 04:45:05 +0000560 arenabase += POOL_SIZE;
Tim Petersd97a1c02002-03-30 06:09:22 +0000561 pool->arenaindex = narenas - 1;
Neil Schemenauera35c6882001-02-27 04:45:05 +0000562 pool->szidx = DUMMY_SIZE_IDX;
563 goto init_pool;
564 }
565 /*
566 * Allocate new arena
567 */
568#ifdef WITH_MEMORY_LIMITS
Tim Petersd97a1c02002-03-30 06:09:22 +0000569 if (!(narenas < MAX_ARENAS)) {
Neil Schemenauera35c6882001-02-27 04:45:05 +0000570 UNLOCK();
571 goto redirect;
572 }
573#endif
Tim Petersd97a1c02002-03-30 06:09:22 +0000574 bp = new_arena();
575 if (bp != NULL)
576 goto commit_pool;
577 UNLOCK();
578 goto redirect;
Neil Schemenauera35c6882001-02-27 04:45:05 +0000579 }
580
581 /* The small block allocator ends here. */
582
Tim Petersd97a1c02002-03-30 06:09:22 +0000583redirect:
Neil Schemenauera35c6882001-02-27 04:45:05 +0000584 /*
585 * Redirect the original request to the underlying (libc) allocator.
586 * We jump here on bigger requests, on error in the code above (as a
587 * last chance to serve the request) or when the max memory limit
588 * has been reached.
589 */
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000590 return (void *)PyMem_MALLOC(nbytes);
Neil Schemenauera35c6882001-02-27 04:45:05 +0000591}
592
593/* free */
594
595void
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000596_PyMalloc_Free(void *p)
Neil Schemenauera35c6882001-02-27 04:45:05 +0000597{
598 poolp pool;
599 poolp next, prev;
600 uint size;
Neil Schemenauera35c6882001-02-27 04:45:05 +0000601
Neil Schemenauera35c6882001-02-27 04:45:05 +0000602 if (p == NULL) /* free(NULL) has no effect */
603 return;
604
Tim Petersd97a1c02002-03-30 06:09:22 +0000605 pool = POOL_ADDR(p);
606 if (ADDRESS_IN_RANGE(p, pool->arenaindex)) {
607 /* We allocated this address. */
608 INCMINE;
609 LOCK();
610 /*
611 * At this point, the pool is not empty
612 */
613 if ((*(block **)p = pool->freeblock) == NULL) {
614 /*
615 * Pool was full
616 */
617 pool->freeblock = (block *)p;
618 --pool->ref.count;
619 /*
620 * Frontlink to used pools
621 * This mimics LRU pool usage for new allocations and
622 * targets optimal filling when several pools contain
623 * blocks of the same size class.
624 */
625 size = pool->szidx;
626 next = usedpools[size + size];
627 prev = next->prevpool;
628 pool->nextpool = next;
629 pool->prevpool = prev;
630 next->prevpool = pool;
631 prev->nextpool = pool;
632 UNLOCK();
633 return;
634 }
635 /*
636 * Pool was not full
637 */
638 pool->freeblock = (block *)p;
639 if (--pool->ref.count != 0) {
640 UNLOCK();
641 return;
642 }
643 /*
644 * Pool is now empty, unlink from used pools
645 */
646 next = pool->nextpool;
647 prev = pool->prevpool;
648 next->prevpool = prev;
649 prev->nextpool = next;
650 /*
651 * Frontlink to free pools
652 * This ensures that previously freed pools will be allocated
653 * later (being not referenced, they are perhaps paged out).
654 */
655 pool->nextpool = freepools;
656 freepools = pool;
657 UNLOCK();
Neil Schemenauera35c6882001-02-27 04:45:05 +0000658 return;
659 }
660
Tim Petersd97a1c02002-03-30 06:09:22 +0000661 /* We did not allocate this address. */
662 INCTHEIRS;
663 PyMem_FREE(p);
Neil Schemenauera35c6882001-02-27 04:45:05 +0000664}
665
666/* realloc */
667
668void *
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000669_PyMalloc_Realloc(void *p, size_t nbytes)
Neil Schemenauera35c6882001-02-27 04:45:05 +0000670{
671 block *bp;
672 poolp pool;
673 uint size;
674
Neil Schemenauera35c6882001-02-27 04:45:05 +0000675 if (p == NULL)
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000676 return _PyMalloc_Malloc(nbytes);
Neil Schemenauera35c6882001-02-27 04:45:05 +0000677
678 /* realloc(p, 0) on big blocks is redirected. */
Tim Petersd97a1c02002-03-30 06:09:22 +0000679 pool = POOL_ADDR(p);
680 if (ADDRESS_IN_RANGE(p, pool->arenaindex)) {
Neil Schemenauera35c6882001-02-27 04:45:05 +0000681 /* We're in charge of this block */
Tim Petersd97a1c02002-03-30 06:09:22 +0000682 INCMINE;
Neil Schemenauera35c6882001-02-27 04:45:05 +0000683 size = (pool->szidx + 1) << ALIGNMENT_SHIFT; /* block size */
684 if (size >= nbytes) {
685 /* Don't bother if a smaller size was requested
686 except for realloc(p, 0) == free(p), ret NULL */
Tim Petersd97a1c02002-03-30 06:09:22 +0000687 /* XXX but Python guarantees that *its* flavor of
688 resize(p, 0) will not do a free or return NULL */
Neil Schemenauera35c6882001-02-27 04:45:05 +0000689 if (nbytes == 0) {
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000690 _PyMalloc_Free(p);
Neil Schemenauera35c6882001-02-27 04:45:05 +0000691 bp = NULL;
692 }
693 else
694 bp = (block *)p;
695 }
696 else {
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000697 bp = (block *)_PyMalloc_Malloc(nbytes);
Neil Schemenauera35c6882001-02-27 04:45:05 +0000698 if (bp != NULL) {
699 memcpy(bp, p, size);
Neil Schemenauer25f3dc22002-03-18 21:06:21 +0000700 _PyMalloc_Free(p);
Neil Schemenauera35c6882001-02-27 04:45:05 +0000701 }
702 }
703 }
Tim Petersd97a1c02002-03-30 06:09:22 +0000704 else {
705 /* We haven't allocated this block */
706 INCTHEIRS;
707 if (nbytes <= SMALL_REQUEST_THRESHOLD && nbytes) {
708 /* small request */
709 size = nbytes;
710 bp = (block *)_PyMalloc_Malloc(nbytes);
711 if (bp != NULL) {
712 memcpy(bp, p, size);
713 _PyMalloc_Free(p);
714 }
715 }
716 else
717 bp = (block *)PyMem_REALLOC(p, nbytes);
718 }
Neil Schemenauera35c6882001-02-27 04:45:05 +0000719 return (void *)bp;
720}
721
Tim Peters1221c0a2002-03-23 00:20:15 +0000722#else /* ! WITH_PYMALLOC */
Tim Petersddea2082002-03-23 10:03:50 +0000723
724/*==========================================================================*/
725/* pymalloc not enabled: Redirect the entry points to the PyMem family. */
Tim Peters62c06ba2002-03-23 22:28:18 +0000726
Tim Petersce7fb9b2002-03-23 00:28:57 +0000727void *
728_PyMalloc_Malloc(size_t n)
Tim Peters1221c0a2002-03-23 00:20:15 +0000729{
730 return PyMem_MALLOC(n);
731}
732
Tim Petersce7fb9b2002-03-23 00:28:57 +0000733void *
734_PyMalloc_Realloc(void *p, size_t n)
Tim Peters1221c0a2002-03-23 00:20:15 +0000735{
736 return PyMem_REALLOC(p, n);
737}
738
739void
740_PyMalloc_Free(void *p)
741{
742 PyMem_FREE(p);
743}
744#endif /* WITH_PYMALLOC */
745
Tim Peters62c06ba2002-03-23 22:28:18 +0000746/*==========================================================================*/
747/* Regardless of whether pymalloc is enabled, export entry points for
748 * the object-oriented pymalloc functions.
749 */
750
Tim Petersce7fb9b2002-03-23 00:28:57 +0000751PyObject *
752_PyMalloc_New(PyTypeObject *tp)
Tim Peters1221c0a2002-03-23 00:20:15 +0000753{
754 PyObject *op;
755 op = (PyObject *) _PyMalloc_MALLOC(_PyObject_SIZE(tp));
756 if (op == NULL)
757 return PyErr_NoMemory();
758 return PyObject_INIT(op, tp);
759}
760
761PyVarObject *
762_PyMalloc_NewVar(PyTypeObject *tp, int nitems)
763{
764 PyVarObject *op;
765 const size_t size = _PyObject_VAR_SIZE(tp, nitems);
766 op = (PyVarObject *) _PyMalloc_MALLOC(size);
767 if (op == NULL)
768 return (PyVarObject *)PyErr_NoMemory();
769 return PyObject_INIT_VAR(op, tp, nitems);
770}
771
772void
773_PyMalloc_Del(PyObject *op)
774{
775 _PyMalloc_FREE(op);
776}
Tim Petersddea2082002-03-23 10:03:50 +0000777
778#ifdef PYMALLOC_DEBUG
779/*==========================================================================*/
Tim Peters62c06ba2002-03-23 22:28:18 +0000780/* A x-platform debugging allocator. This doesn't manage memory directly,
781 * it wraps a real allocator, adding extra debugging info to the memory blocks.
782 */
Tim Petersddea2082002-03-23 10:03:50 +0000783
784#define PYMALLOC_CLEANBYTE 0xCB /* uninitialized memory */
785#define PYMALLOC_DEADBYTE 0xDB /* free()ed memory */
786#define PYMALLOC_FORBIDDENBYTE 0xFB /* unusable memory */
787
788static ulong serialno = 0; /* incremented on each debug {m,re}alloc */
789
Tim Peterse0850172002-03-24 00:34:21 +0000790/* serialno is always incremented via calling this routine. The point is
791 to supply a single place to set a breakpoint.
792*/
793static void
Neil Schemenauerbd02b142002-03-28 21:05:38 +0000794bumpserialno(void)
Tim Peterse0850172002-03-24 00:34:21 +0000795{
796 ++serialno;
797}
798
799
Tim Petersddea2082002-03-23 10:03:50 +0000800/* Read 4 bytes at p as a big-endian ulong. */
801static ulong
802read4(const void *p)
803{
Tim Peters62c06ba2002-03-23 22:28:18 +0000804 const uchar *q = (const uchar *)p;
Tim Petersddea2082002-03-23 10:03:50 +0000805 return ((ulong)q[0] << 24) |
806 ((ulong)q[1] << 16) |
807 ((ulong)q[2] << 8) |
808 (ulong)q[3];
809}
810
811/* Write the 4 least-significant bytes of n as a big-endian unsigned int,
812 MSB at address p, LSB at p+3. */
813static void
814write4(void *p, ulong n)
815{
Tim Peters62c06ba2002-03-23 22:28:18 +0000816 uchar *q = (uchar *)p;
817 q[0] = (uchar)((n >> 24) & 0xff);
818 q[1] = (uchar)((n >> 16) & 0xff);
819 q[2] = (uchar)((n >> 8) & 0xff);
820 q[3] = (uchar)( n & 0xff);
Tim Petersddea2082002-03-23 10:03:50 +0000821}
822
Tim Petersddea2082002-03-23 10:03:50 +0000823/* The debug malloc asks for 16 extra bytes and fills them with useful stuff,
824 here calling the underlying malloc's result p:
825
826p[0:4]
827 Number of bytes originally asked for. 4-byte unsigned integer,
828 big-endian (easier to read in a memory dump).
Tim Petersd1139e02002-03-28 07:32:11 +0000829p[4:8]
Tim Petersddea2082002-03-23 10:03:50 +0000830 Copies of PYMALLOC_FORBIDDENBYTE. Used to catch under- writes
831 and reads.
832p[8:8+n]
833 The requested memory, filled with copies of PYMALLOC_CLEANBYTE.
834 Used to catch reference to uninitialized memory.
835 &p[8] is returned. Note that this is 8-byte aligned if PyMalloc
836 handled the request itself.
837p[8+n:8+n+4]
838 Copies of PYMALLOC_FORBIDDENBYTE. Used to catch over- writes
839 and reads.
840p[8+n+4:8+n+8]
841 A serial number, incremented by 1 on each call to _PyMalloc_DebugMalloc
842 and _PyMalloc_DebugRealloc.
843 4-byte unsigned integer, big-endian.
844 If "bad memory" is detected later, the serial number gives an
845 excellent way to set a breakpoint on the next run, to capture the
846 instant at which this block was passed out.
847*/
848
849void *
Tim Petersd1139e02002-03-28 07:32:11 +0000850_PyMalloc_DebugMalloc(size_t nbytes)
Tim Petersddea2082002-03-23 10:03:50 +0000851{
852 uchar *p; /* base address of malloc'ed block */
Tim Peters62c06ba2002-03-23 22:28:18 +0000853 uchar *tail; /* p + 8 + nbytes == pointer to tail pad bytes */
Tim Petersddea2082002-03-23 10:03:50 +0000854 size_t total; /* nbytes + 16 */
855
Tim Peterse0850172002-03-24 00:34:21 +0000856 bumpserialno();
Tim Petersddea2082002-03-23 10:03:50 +0000857 total = nbytes + 16;
858 if (total < nbytes || (total >> 31) > 1) {
859 /* overflow, or we can't represent it in 4 bytes */
860 /* Obscure: can't do (total >> 32) != 0 instead, because
861 C doesn't define what happens for a right-shift of 32
862 when size_t is a 32-bit type. At least C guarantees
863 size_t is an unsigned type. */
864 return NULL;
865 }
866
Tim Petersd1139e02002-03-28 07:32:11 +0000867 p = _PyMalloc_Malloc(total);
Tim Petersddea2082002-03-23 10:03:50 +0000868 if (p == NULL)
869 return NULL;
870
871 write4(p, nbytes);
Tim Petersd1139e02002-03-28 07:32:11 +0000872 p[4] = p[5] = p[6] = p[7] = PYMALLOC_FORBIDDENBYTE;
Tim Petersddea2082002-03-23 10:03:50 +0000873
874 if (nbytes > 0)
875 memset(p+8, PYMALLOC_CLEANBYTE, nbytes);
876
Tim Peters62c06ba2002-03-23 22:28:18 +0000877 tail = p + 8 + nbytes;
878 tail[0] = tail[1] = tail[2] = tail[3] = PYMALLOC_FORBIDDENBYTE;
879 write4(tail + 4, serialno);
Tim Petersddea2082002-03-23 10:03:50 +0000880
881 return p+8;
882}
883
Tim Peters62c06ba2002-03-23 22:28:18 +0000884/* The debug free first checks the 8 bytes on each end for sanity (in
885 particular, that the PYMALLOC_FORBIDDENBYTEs are still intact).
Tim Petersddea2082002-03-23 10:03:50 +0000886 Then fills the original bytes with PYMALLOC_DEADBYTE.
887 Then calls the underlying free.
888*/
889void
Tim Petersd1139e02002-03-28 07:32:11 +0000890_PyMalloc_DebugFree(void *p)
Tim Petersddea2082002-03-23 10:03:50 +0000891{
Tim Peters62c06ba2002-03-23 22:28:18 +0000892 uchar *q = (uchar *)p;
Tim Petersddea2082002-03-23 10:03:50 +0000893 size_t nbytes;
894
Tim Petersddea2082002-03-23 10:03:50 +0000895 if (p == NULL)
896 return;
Tim Petersddea2082002-03-23 10:03:50 +0000897 _PyMalloc_DebugCheckAddress(p);
898 nbytes = read4(q-8);
899 if (nbytes > 0)
900 memset(q, PYMALLOC_DEADBYTE, nbytes);
Tim Petersd1139e02002-03-28 07:32:11 +0000901 _PyMalloc_Free(q-8);
Tim Petersddea2082002-03-23 10:03:50 +0000902}
903
904void *
Tim Petersd1139e02002-03-28 07:32:11 +0000905_PyMalloc_DebugRealloc(void *p, size_t nbytes)
Tim Petersddea2082002-03-23 10:03:50 +0000906{
907 uchar *q = (uchar *)p;
908 size_t original_nbytes;
Tim Peterse0850172002-03-24 00:34:21 +0000909 void *fresh; /* new memory block, if needed */
Tim Petersddea2082002-03-23 10:03:50 +0000910
Tim Petersddea2082002-03-23 10:03:50 +0000911 if (p == NULL)
Tim Petersd1139e02002-03-28 07:32:11 +0000912 return _PyMalloc_DebugMalloc(nbytes);
Tim Petersddea2082002-03-23 10:03:50 +0000913
Tim Petersddea2082002-03-23 10:03:50 +0000914 _PyMalloc_DebugCheckAddress(p);
Tim Petersddea2082002-03-23 10:03:50 +0000915 original_nbytes = read4(q-8);
916 if (nbytes == original_nbytes) {
917 /* note that this case is likely to be common due to the
918 way Python appends to lists */
Tim Peterse0850172002-03-24 00:34:21 +0000919 bumpserialno();
Tim Petersddea2082002-03-23 10:03:50 +0000920 write4(q + nbytes + 4, serialno);
921 return p;
922 }
923
924 if (nbytes < original_nbytes) {
925 /* shrinking -- leave the guts alone, except to
926 fill the excess with DEADBYTE */
927 const size_t excess = original_nbytes - nbytes;
Tim Peterse0850172002-03-24 00:34:21 +0000928 bumpserialno();
Tim Petersddea2082002-03-23 10:03:50 +0000929 write4(q-8, nbytes);
930 /* kill the excess bytes plus the trailing 8 pad bytes */
Tim Petersddea2082002-03-23 10:03:50 +0000931 q += nbytes;
932 q[0] = q[1] = q[2] = q[3] = PYMALLOC_FORBIDDENBYTE;
933 write4(q+4, serialno);
Tim Petersd1139e02002-03-28 07:32:11 +0000934 memset(q+8, PYMALLOC_DEADBYTE, excess);
Tim Petersddea2082002-03-23 10:03:50 +0000935 return p;
936 }
937
938 /* More memory is needed: get it, copy over the first original_nbytes
939 of the original data, and free the original memory. */
Tim Petersd1139e02002-03-28 07:32:11 +0000940 fresh = _PyMalloc_DebugMalloc(nbytes);
Tim Petersddea2082002-03-23 10:03:50 +0000941 if (fresh != NULL && original_nbytes > 0)
942 memcpy(fresh, p, original_nbytes);
Tim Petersd1139e02002-03-28 07:32:11 +0000943 _PyMalloc_DebugFree(p);
Tim Petersddea2082002-03-23 10:03:50 +0000944 return fresh;
945}
946
947void
948_PyMalloc_DebugCheckAddress(const void *p)
949{
950 const uchar *q = (const uchar *)p;
Tim Petersd1139e02002-03-28 07:32:11 +0000951 char *msg;
952 int i;
Tim Petersddea2082002-03-23 10:03:50 +0000953
Tim Petersd1139e02002-03-28 07:32:11 +0000954 if (p == NULL) {
Tim Petersddea2082002-03-23 10:03:50 +0000955 msg = "didn't expect a NULL pointer";
Tim Petersd1139e02002-03-28 07:32:11 +0000956 goto error;
957 }
Tim Petersddea2082002-03-23 10:03:50 +0000958
Tim Petersd1139e02002-03-28 07:32:11 +0000959 for (i = 4; i >= 1; --i) {
960 if (*(q-i) != PYMALLOC_FORBIDDENBYTE) {
961 msg = "bad leading pad byte";
962 goto error;
963 }
964 }
Tim Petersddea2082002-03-23 10:03:50 +0000965
Tim Petersd1139e02002-03-28 07:32:11 +0000966 {
Tim Petersddea2082002-03-23 10:03:50 +0000967 const ulong nbytes = read4(q-8);
968 const uchar *tail = q + nbytes;
Tim Petersddea2082002-03-23 10:03:50 +0000969 for (i = 0; i < 4; ++i) {
970 if (tail[i] != PYMALLOC_FORBIDDENBYTE) {
971 msg = "bad trailing pad byte";
Tim Petersd1139e02002-03-28 07:32:11 +0000972 goto error;
Tim Petersddea2082002-03-23 10:03:50 +0000973 }
974 }
975 }
976
Tim Petersd1139e02002-03-28 07:32:11 +0000977 return;
978
979error:
980 _PyMalloc_DebugDumpAddress(p);
981 Py_FatalError(msg);
Tim Petersddea2082002-03-23 10:03:50 +0000982}
983
984void
985_PyMalloc_DebugDumpAddress(const void *p)
986{
987 const uchar *q = (const uchar *)p;
988 const uchar *tail;
989 ulong nbytes, serial;
Tim Petersd1139e02002-03-28 07:32:11 +0000990 int i;
Tim Petersddea2082002-03-23 10:03:50 +0000991
992 fprintf(stderr, "Debug memory block at address p=%p:\n", p);
993 if (p == NULL)
994 return;
995
996 nbytes = read4(q-8);
997 fprintf(stderr, " %lu bytes originally allocated\n", nbytes);
Tim Petersddea2082002-03-23 10:03:50 +0000998
999 /* In case this is nuts, check the pad bytes before trying to read up
1000 the serial number (the address deref could blow up). */
1001
Tim Petersd1139e02002-03-28 07:32:11 +00001002 fputs(" the 4 pad bytes at p-4 are ", stderr);
1003 if (*(q-4) == PYMALLOC_FORBIDDENBYTE &&
1004 *(q-3) == PYMALLOC_FORBIDDENBYTE &&
Tim Petersddea2082002-03-23 10:03:50 +00001005 *(q-2) == PYMALLOC_FORBIDDENBYTE &&
1006 *(q-1) == PYMALLOC_FORBIDDENBYTE) {
Tim Peters62c06ba2002-03-23 22:28:18 +00001007 fputs("PYMALLOC_FORBIDDENBYTE, as expected\n", stderr);
Tim Petersddea2082002-03-23 10:03:50 +00001008 }
1009 else {
Tim Petersddea2082002-03-23 10:03:50 +00001010 fprintf(stderr, "not all PYMALLOC_FORBIDDENBYTE (0x%02x):\n",
1011 PYMALLOC_FORBIDDENBYTE);
Tim Petersd1139e02002-03-28 07:32:11 +00001012 for (i = 4; i >= 1; --i) {
Tim Petersddea2082002-03-23 10:03:50 +00001013 const uchar byte = *(q-i);
1014 fprintf(stderr, " at p-%d: 0x%02x", i, byte);
1015 if (byte != PYMALLOC_FORBIDDENBYTE)
1016 fputs(" *** OUCH", stderr);
1017 fputc('\n', stderr);
1018 }
1019 }
1020
1021 tail = q + nbytes;
1022 fprintf(stderr, " the 4 pad bytes at tail=%p are ", tail);
1023 if (tail[0] == PYMALLOC_FORBIDDENBYTE &&
1024 tail[1] == PYMALLOC_FORBIDDENBYTE &&
1025 tail[2] == PYMALLOC_FORBIDDENBYTE &&
1026 tail[3] == PYMALLOC_FORBIDDENBYTE) {
Tim Peters62c06ba2002-03-23 22:28:18 +00001027 fputs("PYMALLOC_FORBIDDENBYTE, as expected\n", stderr);
Tim Petersddea2082002-03-23 10:03:50 +00001028 }
1029 else {
Tim Petersddea2082002-03-23 10:03:50 +00001030 fprintf(stderr, "not all PYMALLOC_FORBIDDENBYTE (0x%02x):\n",
1031 PYMALLOC_FORBIDDENBYTE);
1032 for (i = 0; i < 4; ++i) {
1033 const uchar byte = tail[i];
1034 fprintf(stderr, " at tail+%d: 0x%02x",
1035 i, byte);
1036 if (byte != PYMALLOC_FORBIDDENBYTE)
1037 fputs(" *** OUCH", stderr);
1038 fputc('\n', stderr);
1039 }
1040 }
1041
1042 serial = read4(tail+4);
1043 fprintf(stderr, " the block was made by call #%lu to "
1044 "debug malloc/realloc\n", serial);
1045
1046 if (nbytes > 0) {
1047 int i = 0;
Tim Peters62c06ba2002-03-23 22:28:18 +00001048 fputs(" data at p:", stderr);
Tim Petersddea2082002-03-23 10:03:50 +00001049 /* print up to 8 bytes at the start */
1050 while (q < tail && i < 8) {
1051 fprintf(stderr, " %02x", *q);
1052 ++i;
1053 ++q;
1054 }
1055 /* and up to 8 at the end */
1056 if (q < tail) {
1057 if (tail - q > 8) {
Tim Peters62c06ba2002-03-23 22:28:18 +00001058 fputs(" ...", stderr);
Tim Petersddea2082002-03-23 10:03:50 +00001059 q = tail - 8;
1060 }
1061 while (q < tail) {
1062 fprintf(stderr, " %02x", *q);
1063 ++q;
1064 }
1065 }
Tim Peters62c06ba2002-03-23 22:28:18 +00001066 fputc('\n', stderr);
Tim Petersddea2082002-03-23 10:03:50 +00001067 }
1068}
1069
1070#endif /* PYMALLOC_DEBUG */