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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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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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25 
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28 
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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  } \
209  else \
210  { \
211  /* fixed-size, preallocated pools cannot expand */ \
212  if ((P) && _pool_var(p)->max_elts) \
213  { \
214  clib_warning ("can't expand fixed-size pool"); \
215  os_out_of_memory(); \
216  } \
217  /* Nothing on free list, make a new element and return it. */ \
218  P = _vec_resize (P, \
219  /* length_increment */ 1, \
220  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
221  pool_aligned_header_bytes, \
222  /* align */ (A)); \
223  E = vec_end (P) - 1; \
224  } \
225  if (Z) \
226  memset(E, 0, sizeof(*E)); \
227 } while (0)
228 
229 /** Allocate an object E from a pool P with alignment A */
230 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
231 
232 /** Allocate an object E from a pool P with alignment A and zero it */
233 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
234 
235 /** Allocate an object E from a pool P (unspecified alignment). */
236 #define pool_get(P,E) pool_get_aligned(P,E,0)
237 
238 /** Allocate an object E from a pool P and zero it */
239 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
240 
241 /** See if pool_get will expand the pool or not */
242 #define pool_get_aligned_will_expand(P,YESNO,A) \
243 do { \
244  pool_header_t * _pool_var (p) = pool_header (P); \
245  uword _pool_var (l); \
246  \
247  _pool_var (l) = 0; \
248  if (P) \
249  { \
250  if (_pool_var (p)->max_elts) \
251  _pool_var (l) = _pool_var (p)->max_elts; \
252  else \
253  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
254  } \
255  \
256  /* Free elements, certainly won't expand */ \
257  if (_pool_var (l) > 0) \
258  YESNO=0; \
259  else \
260  { \
261  /* Nothing on free list, make a new element and return it. */ \
262  YESNO = _vec_resize_will_expand \
263  (P, \
264  /* length_increment */ 1, \
265  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
266  pool_aligned_header_bytes, \
267  /* align */ (A)); \
268  } \
269 } while (0)
270 
271 /** Tell the caller if pool get will expand the pool */
272 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
273 
274 /** Use free bitmap to query whether given element is free. */
275 #define pool_is_free(P,E) \
276 ({ \
277  pool_header_t * _pool_var (p) = pool_header (P); \
278  uword _pool_var (i) = (E) - (P); \
279  (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
280 })
281 
282 /** Use free bitmap to query whether given index is free */
283 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
284 
285 /** Free an object E in pool P. */
286 #define pool_put(P,E) \
287 do { \
288  pool_header_t * _pool_var (p) = pool_header (P); \
289  uword _pool_var (l) = (E) - (P); \
290  ASSERT (vec_is_member (P, E)); \
291  ASSERT (! pool_is_free (P, E)); \
292  \
293  /* Add element to free bitmap and to free list. */ \
294  _pool_var (p)->free_bitmap = \
295  clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap, \
296  _pool_var (l)); \
297  \
298  /* Preallocated pool? */ \
299  if (_pool_var (p)->max_elts) \
300  { \
301  ASSERT(_pool_var(l) < _pool_var (p)->max_elts); \
302  _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
303  _pool_var(l); \
304  _vec_len(_pool_var(p)->free_indices) += 1; \
305  } \
306  else \
307  vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
308 } while (0)
309 
310 /** Free pool element with given index. */
311 #define pool_put_index(p,i) \
312 do { \
313  typeof (p) _e = (p) + (i); \
314  pool_put (p, _e); \
315 } while (0)
316 
317 /** Allocate N more free elements to pool (general version). */
318 #define pool_alloc_aligned(P,N,A) \
319 do { \
320  pool_header_t * _p; \
321  \
322  if ((P)) \
323  { \
324  _p = pool_header (P); \
325  if (_p->max_elts) \
326  { \
327  clib_warning ("Can't expand fixed-size pool"); \
328  os_out_of_memory(); \
329  } \
330  } \
331  \
332  (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
333  pool_aligned_header_bytes, \
334  (A)); \
335  _p = pool_header (P); \
336  vec_resize (_p->free_indices, (N)); \
337  _vec_len (_p->free_indices) -= (N); \
338 } while (0)
339 
340 /** Allocate N more free elements to pool (unspecified alignment). */
341 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
342 
343 /**
344  * Return copy of pool with alignment
345  *
346  * @param P pool to copy
347  * @param A alignment (may be zero)
348  * @return copy of pool
349  */
350 #define pool_dup_aligned(P,A) \
351 ({ \
352  typeof (P) _pool_var (new) = 0; \
353  pool_header_t * _pool_var (ph), * _pool_var (new_ph); \
354  u32 _pool_var (n) = pool_len (P); \
355  if ((P)) \
356  { \
357  _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n), \
358  _pool_var (n) * sizeof ((P)[0]), \
359  pool_aligned_header_bytes, (A)); \
360  clib_memcpy_fast (_pool_var (new), (P), \
361  _pool_var (n) * sizeof ((P)[0])); \
362  _pool_var (ph) = pool_header (P); \
363  _pool_var (new_ph) = pool_header (_pool_var (new)); \
364  _pool_var (new_ph)->free_bitmap = \
365  clib_bitmap_dup (_pool_var (ph)->free_bitmap); \
366  _pool_var (new_ph)->free_indices = \
367  vec_dup (_pool_var (ph)->free_indices); \
368  _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts; \
369  } \
370  _pool_var (new); \
371 })
372 
373 /**
374  * Return copy of pool without alignment
375  *
376  * @param P pool to copy
377  * @return copy of pool
378  */
379 #define pool_dup(P) pool_dup_aligned(P,0)
380 
381 /** Low-level free pool operator (do not call directly). */
382 always_inline void *
383 _pool_free (void *v)
384 {
385  pool_header_t *p = pool_header (v);
386  if (!v)
387  return v;
389 
390  if (p->max_elts)
391  {
392  int rv;
393 
394  rv = munmap (p->mmap_base, p->mmap_size);
395  if (rv)
396  clib_unix_warning ("munmap");
397  }
398  else
399  {
400  vec_free (p->free_indices);
402  }
403  return 0;
404 }
405 
406 /** Free a pool. */
407 #define pool_free(p) (p) = _pool_free(p)
408 
409 /** Optimized iteration through pool.
410 
411  @param LO pointer to first element in chunk
412  @param HI pointer to last element in chunk
413  @param POOL pool to iterate across
414  @param BODY operation to perform
415 
416  Optimized version which assumes that BODY is smart enough to
417  process multiple (LOW,HI) chunks. See also pool_foreach().
418  */
419 #define pool_foreach_region(LO,HI,POOL,BODY) \
420 do { \
421  uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
422  uword _pool_var (bl), * _pool_var (b); \
423  pool_header_t * _pool_var (p); \
424  \
425  _pool_var (p) = pool_header (POOL); \
426  _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
427  _pool_var (bl) = vec_len (_pool_var (b)); \
428  _pool_var (len) = vec_len (POOL); \
429  _pool_var (lo) = 0; \
430  \
431  for (_pool_var (i) = 0; \
432  _pool_var (i) <= _pool_var (bl); \
433  _pool_var (i)++) \
434  { \
435  uword _pool_var (m), _pool_var (f); \
436  _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
437  ? _pool_var (b) [_pool_var (i)] \
438  : 1); \
439  while (_pool_var (m) != 0) \
440  { \
441  _pool_var (f) = first_set (_pool_var (m)); \
442  _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
443  + min_log2 (_pool_var (f))); \
444  _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
445  ? _pool_var (hi) : _pool_var (len)); \
446  _pool_var (m) ^= _pool_var (f); \
447  if (_pool_var (hi) > _pool_var (lo)) \
448  { \
449  (LO) = _pool_var (lo); \
450  (HI) = _pool_var (hi); \
451  do { BODY; } while (0); \
452  } \
453  _pool_var (lo) = _pool_var (hi) + 1; \
454  } \
455  } \
456 } while (0)
457 
458 /** Iterate through pool.
459 
460  @param VAR A variable of same type as pool vector to be used as an
461  iterator.
462  @param POOL The pool to iterate across.
463  @param BODY The operation to perform, typically a code block. See
464  the example below.
465 
466  This macro will call @c BODY with each active pool element.
467 
468  It is a bad idea to allocate or free pool element from within
469  @c pool_foreach. Build a vector of indices and dispose of them later.
470  Or call pool_flush.
471 
472 
473  @par Example
474  @code{.c}
475  proc_t *procs; // a pool of processes.
476  proc_t *proc; // pointer to one process; used as the iterator.
477 
478  pool_foreach (proc, procs, ({
479  if (proc->state != PROC_STATE_RUNNING)
480  continue;
481 
482  // check a running proc in some way
483  ...
484  }));
485  @endcode
486 
487  @warning Because @c pool_foreach is a macro, syntax errors can be
488  difficult to find inside @c BODY, let alone actual code bugs. One
489  can temporarily split a complex @c pool_foreach into a trivial
490  @c pool_foreach which builds a vector of active indices, and a
491  vec_foreach() (or plain for-loop) to walk the active index vector.
492  */
493 #define pool_foreach(VAR,POOL,BODY) \
494 do { \
495  uword _pool_foreach_lo, _pool_foreach_hi; \
496  pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
497  ({ \
498  for ((VAR) = (POOL) + _pool_foreach_lo; \
499  (VAR) < (POOL) + _pool_foreach_hi; \
500  (VAR)++) \
501  do { BODY; } while (0); \
502  })); \
503 } while (0)
504 
505 /** Returns pointer to element at given index.
506 
507  ASSERTs that the supplied index is valid.
508  Even though one can write correct code of the form
509  @code
510  p = pool_base + index;
511  @endcode
512  use of @c pool_elt_at_index is strongly suggested.
513  */
514 #define pool_elt_at_index(p,i) \
515 ({ \
516  typeof (p) _e = (p) + (i); \
517  ASSERT (! pool_is_free (p, _e)); \
518  _e; \
519 })
520 
521 /** Return next occupied pool index after @c i, useful for safe iteration. */
522 #define pool_next_index(P,I) \
523 ({ \
524  pool_header_t * _pool_var (p) = pool_header (P); \
525  uword _pool_var (rv) = (I) + 1; \
526  \
527  _pool_var(rv) = \
528  (_pool_var (rv) < vec_len (P) ? \
529  clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
530  : ~0); \
531  _pool_var(rv) = \
532  (_pool_var (rv) < vec_len (P) ? \
533  _pool_var (rv) : ~0); \
534  _pool_var(rv); \
535 })
536 
537 /** Iterate pool by index. */
538 #define pool_foreach_index(i,v,body) \
539  for ((i) = 0; (i) < vec_len (v); (i)++) \
540  { \
541  if (! pool_is_free_index ((v), (i))) \
542  do { body; } while (0); \
543  }
544 
545 /**
546  * @brief Remove all elements from a pool in a safe way
547  *
548  * @param VAR each element in the pool
549  * @param POOL The pool to flush
550  * @param BODY The actions to perform on each element before it is returned to
551  * the pool. i.e. before it is 'freed'
552  */
553 #define pool_flush(VAR, POOL, BODY) \
554 { \
555  uword *_pool_var(ii), *_pool_var(dv) = NULL; \
556  \
557  pool_foreach((VAR), (POOL), \
558  ({ \
559  vec_add1(_pool_var(dv), (VAR) - (POOL)); \
560  })); \
561  vec_foreach(_pool_var(ii), _pool_var(dv)) \
562  { \
563  (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
564  do { BODY; } while (0); \
565  pool_put((POOL), (VAR)); \
566  } \
567  vec_free(_pool_var(dv)); \
568 }
569 
570 #endif /* included_pool_h */
571 
572 /*
573  * fd.io coding-style-patch-verification: ON
574  *
575  * Local Variables:
576  * eval: (c-set-style "gnu")
577  * End:
578  */
#define vec_validate(V, I)
Make sure vector is long enough for given index (no header, unspecified alignment) ...
Definition: vec.h:439
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
#define always_inline
Definition: clib.h:98
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 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:341
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:328
#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