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Vector Packet Processing
pool.h
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1 /*
2  * Copyright (c) 2015 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
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14  */
15 /*
16  Copyright (c) 2001, 2002, 2003, 2004 Eliot Dresselhaus
17 
18  Permission is hereby granted, free of charge, to any person obtaining
19  a copy of this software and associated documentation files (the
20  "Software"), to deal in the Software without restriction, including
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24  the following conditions:
25 
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27  included in all copies or substantial portions of the Software.
28 
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31  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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34  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
35  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
36 */
37 /** @file
38  * @brief Fixed length block allocator.
39  Pools are built from clib vectors and bitmaps. Use pools when
40  repeatedly allocating and freeing fixed-size data. Pools are
41  fast, and avoid memory fragmentation.
42  */
43 
44 #ifndef included_pool_h
45 #define included_pool_h
46 
47 #include <vppinfra/bitmap.h>
48 #include <vppinfra/error.h>
49 #include <vppinfra/mheap.h>
50 
51 
52 typedef struct
53 {
54  /** Bitmap of indices of free objects. */
56 
57  /** Vector of free indices. One element for each set bit in bitmap. */
59 
60  /* The following fields are set for fixed-size, preallocated pools */
61 
62  /** Maximum size of the pool, in elements */
64 
65  /** mmap segment info: base + length */
68 
70 
71 /** Align pool header so that pointers are naturally aligned. */
72 #define pool_aligned_header_bytes \
73  vec_aligned_header_bytes (sizeof (pool_header_t), sizeof (void *))
74 
75 /** Get pool header from user pool pointer */
77 pool_header (void *v)
78 {
79  return vec_aligned_header (v, sizeof (pool_header_t), sizeof (void *));
80 }
81 
82 extern void _pool_init_fixed (void **, u32, u32);
83 extern void fpool_free (void *);
84 
85 /** initialize a fixed-size, preallocated pool */
86 #define pool_init_fixed(pool,max_elts) \
87 { \
88  _pool_init_fixed((void **)&(pool),sizeof(pool[0]),max_elts); \
89 }
90 
91 /** Validate a pool */
92 always_inline void
93 pool_validate (void *v)
94 {
95  pool_header_t *p = pool_header (v);
96  uword i, n_free_bitmap;
97 
98  if (!v)
99  return;
100 
101  n_free_bitmap = clib_bitmap_count_set_bits (p->free_bitmap);
102  ASSERT (n_free_bitmap == vec_len (p->free_indices));
103  for (i = 0; i < vec_len (p->free_indices); i++)
104  ASSERT (clib_bitmap_get (p->free_bitmap, p->free_indices[i]) == 1);
105 }
106 
107 always_inline void
109 {
110  pool_header_t *p = pool_header (v);
111 
112  if (v)
113  vec_validate (p->free_bitmap, index / BITS (uword));
114 }
115 
116 #define pool_validate_index(v,i) \
117 do { \
118  uword __pool_validate_index = (i); \
119  vec_validate_ha ((v), __pool_validate_index, \
120  pool_aligned_header_bytes, /* align */ 0); \
121  pool_header_validate_index ((v), __pool_validate_index); \
122 } while (0)
123 
124 /** Number of active elements in a pool.
125  * @return Number of active elements in a pool
126  */
128 pool_elts (void *v)
129 {
130  uword ret = vec_len (v);
131  if (v)
132  ret -= vec_len (pool_header (v)->free_indices);
133  return ret;
134 }
135 
136 /** Number of elements in pool vector.
137 
138  @note You probably want to call pool_elts() instead.
139 */
140 #define pool_len(p) vec_len(p)
141 
142 /** Number of elements in pool vector (usable as an lvalue)
143 
144  @note You probably don't want to use this macro.
145 */
146 #define _pool_len(p) _vec_len(p)
147 
148 /** Memory usage of pool header. */
151 {
152  pool_header_t *p = pool_header (v);
153 
154  if (!v)
155  return 0;
156 
157  return vec_bytes (p->free_bitmap) + vec_bytes (p->free_indices);
158 }
159 
160 /** Memory usage of pool. */
161 #define pool_bytes(P) (vec_bytes (P) + pool_header_bytes (P))
162 
163 /** Local variable naming macro. */
164 #define _pool_var(v) _pool_##v
165 
166 /** Queries whether pool has at least N_FREE free elements. */
168 pool_free_elts (void *v)
169 {
170  pool_header_t *p = pool_header (v);
171  uword n_free = 0;
172 
173  if (v)
174  {
175  n_free += vec_len (p->free_indices);
176 
177  /* Space left at end of vector? */
178  n_free += vec_capacity (v, sizeof (p[0])) - vec_len (v);
179  }
180 
181  return n_free;
182 }
183 
184 /** Allocate an object E from a pool P (general version).
185 
186  First search free list. If nothing is free extend vector of objects.
187 */
188 #define _pool_get_aligned_internal(P,E,A,Z) \
189 do { \
190  pool_header_t * _pool_var (p) = pool_header (P); \
191  uword _pool_var (l); \
192  \
193  STATIC_ASSERT(A==0 || ((A % sizeof(P[0]))==0) || ((sizeof(P[0]) % A) == 0), \
194  "Pool aligned alloc of incorrectly sized object"); \
195  _pool_var (l) = 0; \
196  if (P) \
197  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
198  \
199  if (_pool_var (l) > 0) \
200  { \
201  /* Return free element from free list. */ \
202  uword _pool_var (i) = _pool_var (p)->free_indices[_pool_var (l) - 1]; \
203  (E) = (P) + _pool_var (i); \
204  _pool_var (p)->free_bitmap = \
205  clib_bitmap_andnoti_notrim (_pool_var (p)->free_bitmap, \
206  _pool_var (i)); \
207  _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
208  CLIB_MEM_UNPOISON((E), sizeof((E)[0])); \
209  } \
210  else \
211  { \
212  /* fixed-size, preallocated pools cannot expand */ \
213  if ((P) && _pool_var(p)->max_elts) \
214  { \
215  clib_warning ("can't expand fixed-size pool"); \
216  os_out_of_memory(); \
217  } \
218  /* Nothing on free list, make a new element and return it. */ \
219  P = _vec_resize (P, \
220  /* length_increment */ 1, \
221  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
222  pool_aligned_header_bytes, \
223  /* align */ (A)); \
224  E = vec_end (P) - 1; \
225  } \
226  if (Z) \
227  memset(E, 0, sizeof(*E)); \
228 } while (0)
229 
230 /** Allocate an object E from a pool P with alignment A */
231 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
232 
233 /** Allocate an object E from a pool P with alignment A and zero it */
234 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
235 
236 /** Allocate an object E from a pool P (unspecified alignment). */
237 #define pool_get(P,E) pool_get_aligned(P,E,0)
238 
239 /** Allocate an object E from a pool P and zero it */
240 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
241 
242 /** See if pool_get will expand the pool or not */
243 #define pool_get_aligned_will_expand(P,YESNO,A) \
244 do { \
245  pool_header_t * _pool_var (p) = pool_header (P); \
246  uword _pool_var (l); \
247  \
248  _pool_var (l) = 0; \
249  if (P) \
250  { \
251  if (_pool_var (p)->max_elts) \
252  _pool_var (l) = _pool_var (p)->max_elts; \
253  else \
254  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
255  } \
256  \
257  /* Free elements, certainly won't expand */ \
258  if (_pool_var (l) > 0) \
259  YESNO=0; \
260  else \
261  { \
262  /* Nothing on free list, make a new element and return it. */ \
263  YESNO = _vec_resize_will_expand \
264  (P, \
265  /* length_increment */ 1, \
266  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
267  pool_aligned_header_bytes, \
268  /* align */ (A)); \
269  } \
270 } while (0)
271 
272 /** Tell the caller if pool get will expand the pool */
273 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
274 
275 /** Use free bitmap to query whether given element is free. */
276 #define pool_is_free(P,E) \
277 ({ \
278  pool_header_t * _pool_var (p) = pool_header (P); \
279  uword _pool_var (i) = (E) - (P); \
280  (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
281 })
282 
283 /** Use free bitmap to query whether given index is free */
284 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
285 
286 /** Free an object E in pool P. */
287 #define pool_put(P,E) \
288 do { \
289  typeof (P) _pool_var(p__) = (P); \
290  typeof (E) _pool_var(e__) = (E); \
291  pool_header_t * _pool_var (p) = pool_header (_pool_var(p__)); \
292  uword _pool_var (l) = _pool_var(e__) - _pool_var(p__); \
293  ASSERT (vec_is_member (_pool_var(p__), _pool_var(e__))); \
294  ASSERT (! pool_is_free (_pool_var(p__), _pool_var(e__))); \
295  \
296  /* Add element to free bitmap and to free list. */ \
297  _pool_var (p)->free_bitmap = \
298  clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap, \
299  _pool_var (l)); \
300  \
301  /* Preallocated pool? */ \
302  if (_pool_var (p)->max_elts) \
303  { \
304  ASSERT(_pool_var(l) < _pool_var (p)->max_elts); \
305  _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
306  _pool_var(l); \
307  _vec_len(_pool_var(p)->free_indices) += 1; \
308  } \
309  else \
310  vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
311  \
312  CLIB_MEM_POISON(_pool_var(e__), sizeof(_pool_var(e__)[0])); \
313 } while (0)
314 
315 /** Free pool element with given index. */
316 #define pool_put_index(p,i) \
317 do { \
318  typeof (p) _e = (p) + (i); \
319  pool_put (p, _e); \
320 } while (0)
321 
322 /** Allocate N more free elements to pool (general version). */
323 #define pool_alloc_aligned(P,N,A) \
324 do { \
325  pool_header_t * _p; \
326  \
327  if ((P)) \
328  { \
329  _p = pool_header (P); \
330  if (_p->max_elts) \
331  { \
332  clib_warning ("Can't expand fixed-size pool"); \
333  os_out_of_memory(); \
334  } \
335  } \
336  \
337  (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
338  pool_aligned_header_bytes, \
339  (A)); \
340  _p = pool_header (P); \
341  vec_resize (_p->free_indices, (N)); \
342  _vec_len (_p->free_indices) -= (N); \
343 } while (0)
344 
345 /** Allocate N more free elements to pool (unspecified alignment). */
346 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
347 
348 /**
349  * Return copy of pool with alignment
350  *
351  * @param P pool to copy
352  * @param A alignment (may be zero)
353  * @return copy of pool
354  */
355 #define pool_dup_aligned(P,A) \
356 ({ \
357  typeof (P) _pool_var (new) = 0; \
358  pool_header_t * _pool_var (ph), * _pool_var (new_ph); \
359  u32 _pool_var (n) = pool_len (P); \
360  if ((P)) \
361  { \
362  _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n), \
363  _pool_var (n) * sizeof ((P)[0]), \
364  pool_aligned_header_bytes, (A)); \
365  clib_memcpy_fast (_pool_var (new), (P), \
366  _pool_var (n) * sizeof ((P)[0])); \
367  _pool_var (ph) = pool_header (P); \
368  _pool_var (new_ph) = pool_header (_pool_var (new)); \
369  _pool_var (new_ph)->free_bitmap = \
370  clib_bitmap_dup (_pool_var (ph)->free_bitmap); \
371  _pool_var (new_ph)->free_indices = \
372  vec_dup (_pool_var (ph)->free_indices); \
373  _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts; \
374  } \
375  _pool_var (new); \
376 })
377 
378 /**
379  * Return copy of pool without alignment
380  *
381  * @param P pool to copy
382  * @return copy of pool
383  */
384 #define pool_dup(P) pool_dup_aligned(P,0)
385 
386 /** Low-level free pool operator (do not call directly). */
387 always_inline void *
388 _pool_free (void *v)
389 {
390  pool_header_t *p = pool_header (v);
391  if (!v)
392  return v;
394 
395  if (p->max_elts)
396  {
397  int rv;
398 
399  rv = munmap (p->mmap_base, p->mmap_size);
400  if (rv)
401  clib_unix_warning ("munmap");
402  }
403  else
404  {
405  vec_free (p->free_indices);
407  }
408  return 0;
409 }
410 
411 /** Free a pool. */
412 #define pool_free(p) (p) = _pool_free(p)
413 
414 /** Optimized iteration through pool.
415 
416  @param LO pointer to first element in chunk
417  @param HI pointer to last element in chunk
418  @param POOL pool to iterate across
419  @param BODY operation to perform
420 
421  Optimized version which assumes that BODY is smart enough to
422  process multiple (LOW,HI) chunks. See also pool_foreach().
423  */
424 #define pool_foreach_region(LO,HI,POOL,BODY) \
425 do { \
426  uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
427  uword _pool_var (bl), * _pool_var (b); \
428  pool_header_t * _pool_var (p); \
429  \
430  _pool_var (p) = pool_header (POOL); \
431  _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
432  _pool_var (bl) = vec_len (_pool_var (b)); \
433  _pool_var (len) = vec_len (POOL); \
434  _pool_var (lo) = 0; \
435  \
436  for (_pool_var (i) = 0; \
437  _pool_var (i) <= _pool_var (bl); \
438  _pool_var (i)++) \
439  { \
440  uword _pool_var (m), _pool_var (f); \
441  _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
442  ? _pool_var (b) [_pool_var (i)] \
443  : 1); \
444  while (_pool_var (m) != 0) \
445  { \
446  _pool_var (f) = first_set (_pool_var (m)); \
447  _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
448  + min_log2 (_pool_var (f))); \
449  _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
450  ? _pool_var (hi) : _pool_var (len)); \
451  _pool_var (m) ^= _pool_var (f); \
452  if (_pool_var (hi) > _pool_var (lo)) \
453  { \
454  (LO) = _pool_var (lo); \
455  (HI) = _pool_var (hi); \
456  do { BODY; } while (0); \
457  } \
458  _pool_var (lo) = _pool_var (hi) + 1; \
459  } \
460  } \
461 } while (0)
462 
463 /** Iterate through pool.
464 
465  @param VAR A variable of same type as pool vector to be used as an
466  iterator.
467  @param POOL The pool to iterate across.
468  @param BODY The operation to perform, typically a code block. See
469  the example below.
470 
471  This macro will call @c BODY with each active pool element.
472 
473  It is a bad idea to allocate or free pool element from within
474  @c pool_foreach. Build a vector of indices and dispose of them later.
475  Or call pool_flush.
476 
477 
478  @par Example
479  @code{.c}
480  proc_t *procs; // a pool of processes.
481  proc_t *proc; // pointer to one process; used as the iterator.
482 
483  pool_foreach (proc, procs, ({
484  if (proc->state != PROC_STATE_RUNNING)
485  continue;
486 
487  // check a running proc in some way
488  ...
489  }));
490  @endcode
491 
492  @warning Because @c pool_foreach is a macro, syntax errors can be
493  difficult to find inside @c BODY, let alone actual code bugs. One
494  can temporarily split a complex @c pool_foreach into a trivial
495  @c pool_foreach which builds a vector of active indices, and a
496  vec_foreach() (or plain for-loop) to walk the active index vector.
497  */
498 #define pool_foreach(VAR,POOL,BODY) \
499 do { \
500  uword _pool_foreach_lo, _pool_foreach_hi; \
501  pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
502  ({ \
503  for ((VAR) = (POOL) + _pool_foreach_lo; \
504  (VAR) < (POOL) + _pool_foreach_hi; \
505  (VAR)++) \
506  do { BODY; } while (0); \
507  })); \
508 } while (0)
509 
510 /** Returns pointer to element at given index.
511 
512  ASSERTs that the supplied index is valid.
513  Even though one can write correct code of the form
514  @code
515  p = pool_base + index;
516  @endcode
517  use of @c pool_elt_at_index is strongly suggested.
518  */
519 #define pool_elt_at_index(p,i) \
520 ({ \
521  typeof (p) _e = (p) + (i); \
522  ASSERT (! pool_is_free (p, _e)); \
523  _e; \
524 })
525 
526 /** Return next occupied pool index after @c i, useful for safe iteration. */
527 #define pool_next_index(P,I) \
528 ({ \
529  pool_header_t * _pool_var (p) = pool_header (P); \
530  uword _pool_var (rv) = (I) + 1; \
531  \
532  _pool_var(rv) = \
533  (_pool_var (rv) < vec_len (P) ? \
534  clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
535  : ~0); \
536  _pool_var(rv) = \
537  (_pool_var (rv) < vec_len (P) ? \
538  _pool_var (rv) : ~0); \
539  _pool_var(rv); \
540 })
541 
542 /** Iterate pool by index. */
543 #define pool_foreach_index(i,v,body) \
544  for ((i) = 0; (i) < vec_len (v); (i)++) \
545  { \
546  if (! pool_is_free_index ((v), (i))) \
547  do { body; } while (0); \
548  }
549 
550 /**
551  * @brief Remove all elements from a pool in a safe way
552  *
553  * @param VAR each element in the pool
554  * @param POOL The pool to flush
555  * @param BODY The actions to perform on each element before it is returned to
556  * the pool. i.e. before it is 'freed'
557  */
558 #define pool_flush(VAR, POOL, BODY) \
559 { \
560  uword *_pool_var(ii), *_pool_var(dv) = NULL; \
561  \
562  pool_foreach((VAR), (POOL), \
563  ({ \
564  vec_add1(_pool_var(dv), (VAR) - (POOL)); \
565  })); \
566  vec_foreach(_pool_var(ii), _pool_var(dv)) \
567  { \
568  (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
569  do { BODY; } while (0); \
570  pool_put((POOL), (VAR)); \
571  } \
572  vec_free(_pool_var(dv)); \
573 }
574 
575 #endif /* included_pool_h */
576 
577 /*
578  * fd.io coding-style-patch-verification: ON
579  *
580  * Local Variables:
581  * eval: (c-set-style "gnu")
582  * End:
583  */
#define vec_validate(V, I)
Make sure vector is long enough for given index (no header, unspecified alignment) ...
Definition: vec.h:440
u64 mmap_size
Definition: pool.h:67
unsigned long u64
Definition: types.h:89
static void pool_header_validate_index(void *v, uword index)
Definition: pool.h:108
u32 * free_indices
Vector of free indices.
Definition: pool.h:58
int i
#define vec_bytes(v)
Number of data bytes in vector.
unsigned char u8
Definition: types.h:56
unsigned int u32
Definition: types.h:88
void fpool_free(void *)
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:77
#define always_inline
Definition: ipsec.h:28
#define pool_aligned_header_bytes
Align pool header so that pointers are naturally aligned.
Definition: pool.h:72
static uword pool_header_bytes(void *v)
Memory usage of pool header.
Definition: pool.h:150
static void pool_validate(void *v)
Validate a pool.
Definition: pool.h:93
#define vec_free(V)
Free vector&#39;s memory (no header).
Definition: vec.h:342
static void * vec_aligned_header(void *v, uword header_bytes, uword align)
#define vec_capacity(v, b)
Total number of bytes that can fit in vector with current allocation.
static uword clib_bitmap_get(uword *ai, uword i)
Gets the ith bit value from a bitmap.
Definition: bitmap.h:197
#define ASSERT(truth)
Bitmaps built as vectors of machine words.
#define clib_bitmap_free(v)
Free a bitmap.
Definition: bitmap.h:92
uword * free_bitmap
Bitmap of indices of free objects.
Definition: pool.h:55
static uword clib_bitmap_count_set_bits(uword *ai)
Return the number of set bits in a bitmap.
Definition: bitmap.h:462
#define vec_free_h(V, H)
Free vector&#39;s memory (general version)
Definition: vec.h:329
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
u64 uword
Definition: types.h:112
#define clib_unix_warning(format, args...)
Definition: error.h:68
u32 max_elts
Maximum size of the pool, in elements.
Definition: pool.h:63
#define BITS(x)
Definition: clib.h:61
static uword pool_free_elts(void *v)
Queries whether pool has at least N_FREE free elements.
Definition: pool.h:168
u8 * mmap_base
mmap segment info: base + length
Definition: pool.h:66
static uword pool_elts(void *v)
Number of active elements in a pool.
Definition: pool.h:128