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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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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_numa(P,E,A,Z,N) \
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) \
194  || ((sizeof(P[0]) % A) == 0), \
195  "Pool aligned alloc of incorrectly sized object"); \
196  _pool_var (l) = 0; \
197  if (P) \
198  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
199  \
200  if (_pool_var (l) > 0) \
201  { \
202  /* Return free element from free list. */ \
203  uword _pool_var (i) = \
204  _pool_var (p)->free_indices[_pool_var (l) - 1]; \
205  (E) = (P) + _pool_var (i); \
206  _pool_var (p)->free_bitmap = \
207  clib_bitmap_andnoti_notrim (_pool_var (p)->free_bitmap, \
208  _pool_var (i)); \
209  _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
210  CLIB_MEM_UNPOISON((E), sizeof((E)[0])); \
211  } \
212  else \
213  { \
214  /* fixed-size, preallocated pools cannot expand */ \
215  if ((P) && _pool_var(p)->max_elts) \
216  { \
217  clib_warning ("can't expand fixed-size pool"); \
218  os_out_of_memory(); \
219  } \
220  /* Nothing on free list, make a new element and return it. */ \
221  P = _vec_resize_numa (P, \
222  /* length_increment */ 1, \
223  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
224  pool_aligned_header_bytes, \
225  /* align */ (A), \
226  /* numa */ (N)); \
227  E = vec_end (P) - 1; \
228  } \
229  if (Z) \
230  memset(E, 0, sizeof(*E)); \
231 } while (0)
232 
233 #define pool_get_aligned_zero_numa(P,E,A,Z,S) \
234  _pool_get_aligned_internal_numa(P,E,A,Z,S)
235 
236 #define pool_get_aligned_numa(P,E,A,S) \
237  _pool_get_aligned_internal_numa(P,E,A,0/*zero*/,S)
238 
239 #define pool_get_numa(P,E,S) \
240  _pool_get_aligned_internal_numa(P,E,0/*align*/,0/*zero*/,S)
241 
242 #define _pool_get_aligned_internal(P,E,A,Z) \
243  _pool_get_aligned_internal_numa(P,E,A,Z,VEC_NUMA_UNSPECIFIED)
244 
245 /** Allocate an object E from a pool P with alignment A */
246 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
247 
248 /** Allocate an object E from a pool P with alignment A and zero it */
249 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
250 
251 /** Allocate an object E from a pool P (unspecified alignment). */
252 #define pool_get(P,E) pool_get_aligned(P,E,0)
253 
254 /** Allocate an object E from a pool P and zero it */
255 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
256 
257 /** See if pool_get will expand the pool or not */
258 #define pool_get_aligned_will_expand(P,YESNO,A) \
259 do { \
260  pool_header_t * _pool_var (p) = pool_header (P); \
261  uword _pool_var (l); \
262  \
263  _pool_var (l) = 0; \
264  if (P) \
265  { \
266  if (_pool_var (p)->max_elts) \
267  _pool_var (l) = _pool_var (p)->max_elts; \
268  else \
269  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
270  } \
271  \
272  /* Free elements, certainly won't expand */ \
273  if (_pool_var (l) > 0) \
274  YESNO=0; \
275  else \
276  { \
277  /* Nothing on free list, make a new element and return it. */ \
278  YESNO = _vec_resize_will_expand \
279  (P, \
280  /* length_increment */ 1, \
281  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
282  pool_aligned_header_bytes, \
283  /* align */ (A)); \
284  } \
285 } while (0)
286 
287 /** Tell the caller if pool get will expand the pool */
288 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
289 
290 /** Use free bitmap to query whether given element is free. */
291 #define pool_is_free(P,E) \
292 ({ \
293  pool_header_t * _pool_var (p) = pool_header (P); \
294  uword _pool_var (i) = (E) - (P); \
295  (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
296 })
297 
298 /** Use free bitmap to query whether given index is free */
299 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
300 
301 /** Free an object E in pool P. */
302 #define pool_put(P,E) \
303 do { \
304  typeof (P) _pool_var(p__) = (P); \
305  typeof (E) _pool_var(e__) = (E); \
306  pool_header_t * _pool_var (p) = pool_header (_pool_var(p__)); \
307  uword _pool_var (l) = _pool_var(e__) - _pool_var(p__); \
308  ASSERT (vec_is_member (_pool_var(p__), _pool_var(e__))); \
309  ASSERT (! pool_is_free (_pool_var(p__), _pool_var(e__))); \
310  \
311  /* Add element to free bitmap and to free list. */ \
312  _pool_var (p)->free_bitmap = \
313  clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap, \
314  _pool_var (l)); \
315  \
316  /* Preallocated pool? */ \
317  if (_pool_var (p)->max_elts) \
318  { \
319  ASSERT(_pool_var(l) < _pool_var (p)->max_elts); \
320  _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
321  _pool_var(l); \
322  _vec_len(_pool_var(p)->free_indices) += 1; \
323  } \
324  else \
325  vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
326  \
327  CLIB_MEM_POISON(_pool_var(e__), sizeof(_pool_var(e__)[0])); \
328 } while (0)
329 
330 /** Free pool element with given index. */
331 #define pool_put_index(p,i) \
332 do { \
333  typeof (p) _e = (p) + (i); \
334  pool_put (p, _e); \
335 } while (0)
336 
337 /** Allocate N more free elements to pool (general version). */
338 #define pool_alloc_aligned(P,N,A) \
339 do { \
340  pool_header_t * _p; \
341  \
342  if ((P)) \
343  { \
344  _p = pool_header (P); \
345  if (_p->max_elts) \
346  { \
347  clib_warning ("Can't expand fixed-size pool"); \
348  os_out_of_memory(); \
349  } \
350  } \
351  \
352  (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
353  pool_aligned_header_bytes, \
354  (A)); \
355  _p = pool_header (P); \
356  vec_resize (_p->free_indices, (N)); \
357  _vec_len (_p->free_indices) -= (N); \
358 } while (0)
359 
360 /** Allocate N more free elements to pool (unspecified alignment). */
361 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
362 
363 /**
364  * Return copy of pool with alignment
365  *
366  * @param P pool to copy
367  * @param A alignment (may be zero)
368  * @return copy of pool
369  */
370 #define pool_dup_aligned(P,A) \
371 ({ \
372  typeof (P) _pool_var (new) = 0; \
373  pool_header_t * _pool_var (ph), * _pool_var (new_ph); \
374  u32 _pool_var (n) = pool_len (P); \
375  if ((P)) \
376  { \
377  _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n), \
378  _pool_var (n) * sizeof ((P)[0]), \
379  pool_aligned_header_bytes, (A)); \
380  clib_memcpy_fast (_pool_var (new), (P), \
381  _pool_var (n) * sizeof ((P)[0])); \
382  _pool_var (ph) = pool_header (P); \
383  _pool_var (new_ph) = pool_header (_pool_var (new)); \
384  _pool_var (new_ph)->free_bitmap = \
385  clib_bitmap_dup (_pool_var (ph)->free_bitmap); \
386  _pool_var (new_ph)->free_indices = \
387  vec_dup (_pool_var (ph)->free_indices); \
388  _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts; \
389  } \
390  _pool_var (new); \
391 })
392 
393 /**
394  * Return copy of pool without alignment
395  *
396  * @param P pool to copy
397  * @return copy of pool
398  */
399 #define pool_dup(P) pool_dup_aligned(P,0)
400 
401 /** Low-level free pool operator (do not call directly). */
402 always_inline void *
403 _pool_free (void *v)
404 {
405  pool_header_t *p = pool_header (v);
406  if (!v)
407  return v;
409 
410  if (p->max_elts)
411  {
412  int rv;
413 
414  rv = munmap (p->mmap_base, p->mmap_size);
415  if (rv)
416  clib_unix_warning ("munmap");
417  }
418  else
419  {
420  vec_free (p->free_indices);
422  }
423  return 0;
424 }
425 
426 /** Free a pool. */
427 #define pool_free(p) (p) = _pool_free(p)
428 
429 /** Optimized iteration through pool.
430 
431  @param LO pointer to first element in chunk
432  @param HI pointer to last element in chunk
433  @param POOL pool to iterate across
434  @param BODY operation to perform
435 
436  Optimized version which assumes that BODY is smart enough to
437  process multiple (LOW,HI) chunks. See also pool_foreach().
438  */
439 #define pool_foreach_region(LO,HI,POOL,BODY) \
440 do { \
441  uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
442  uword _pool_var (bl), * _pool_var (b); \
443  pool_header_t * _pool_var (p); \
444  \
445  _pool_var (p) = pool_header (POOL); \
446  _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
447  _pool_var (bl) = vec_len (_pool_var (b)); \
448  _pool_var (len) = vec_len (POOL); \
449  _pool_var (lo) = 0; \
450  \
451  for (_pool_var (i) = 0; \
452  _pool_var (i) <= _pool_var (bl); \
453  _pool_var (i)++) \
454  { \
455  uword _pool_var (m), _pool_var (f); \
456  _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
457  ? _pool_var (b) [_pool_var (i)] \
458  : 1); \
459  while (_pool_var (m) != 0) \
460  { \
461  _pool_var (f) = first_set (_pool_var (m)); \
462  _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
463  + min_log2 (_pool_var (f))); \
464  _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
465  ? _pool_var (hi) : _pool_var (len)); \
466  _pool_var (m) ^= _pool_var (f); \
467  if (_pool_var (hi) > _pool_var (lo)) \
468  { \
469  (LO) = _pool_var (lo); \
470  (HI) = _pool_var (hi); \
471  do { BODY; } while (0); \
472  } \
473  _pool_var (lo) = _pool_var (hi) + 1; \
474  } \
475  } \
476 } while (0)
477 
478 /** Iterate through pool.
479 
480  @param VAR A variable of same type as pool vector to be used as an
481  iterator.
482  @param POOL The pool to iterate across.
483  @param BODY The operation to perform, typically a code block. See
484  the example below.
485 
486  This macro will call @c BODY with each active pool element.
487 
488  It is a bad idea to allocate or free pool element from within
489  @c pool_foreach. Build a vector of indices and dispose of them later.
490  Or call pool_flush.
491 
492 
493  @par Example
494  @code{.c}
495  proc_t *procs; // a pool of processes.
496  proc_t *proc; // pointer to one process; used as the iterator.
497 
498  pool_foreach (proc, procs, ({
499  if (proc->state != PROC_STATE_RUNNING)
500  continue;
501 
502  // check a running proc in some way
503  ...
504  }));
505  @endcode
506 
507  @warning Because @c pool_foreach is a macro, syntax errors can be
508  difficult to find inside @c BODY, let alone actual code bugs. One
509  can temporarily split a complex @c pool_foreach into a trivial
510  @c pool_foreach which builds a vector of active indices, and a
511  vec_foreach() (or plain for-loop) to walk the active index vector.
512  */
513 #define pool_foreach(VAR,POOL,BODY) \
514 do { \
515  uword _pool_foreach_lo, _pool_foreach_hi; \
516  pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
517  ({ \
518  for ((VAR) = (POOL) + _pool_foreach_lo; \
519  (VAR) < (POOL) + _pool_foreach_hi; \
520  (VAR)++) \
521  do { BODY; } while (0); \
522  })); \
523 } while (0)
524 
525 /** Returns pointer to element at given index.
526 
527  ASSERTs that the supplied index is valid.
528  Even though one can write correct code of the form
529  @code
530  p = pool_base + index;
531  @endcode
532  use of @c pool_elt_at_index is strongly suggested.
533  */
534 #define pool_elt_at_index(p,i) \
535 ({ \
536  typeof (p) _e = (p) + (i); \
537  ASSERT (! pool_is_free (p, _e)); \
538  _e; \
539 })
540 
541 /** Return next occupied pool index after @c i, useful for safe iteration. */
542 #define pool_next_index(P,I) \
543 ({ \
544  pool_header_t * _pool_var (p) = pool_header (P); \
545  uword _pool_var (rv) = (I) + 1; \
546  \
547  _pool_var(rv) = \
548  (_pool_var (rv) < vec_len (P) ? \
549  clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
550  : ~0); \
551  _pool_var(rv) = \
552  (_pool_var (rv) < vec_len (P) ? \
553  _pool_var (rv) : ~0); \
554  _pool_var(rv); \
555 })
556 
557 /** Iterate pool by index. */
558 #define pool_foreach_index(i,v,body) \
559  for ((i) = 0; (i) < vec_len (v); (i)++) \
560  { \
561  if (! pool_is_free_index ((v), (i))) \
562  do { body; } while (0); \
563  }
564 
565 /**
566  * @brief Remove all elements from a pool in a safe way
567  *
568  * @param VAR each element in the pool
569  * @param POOL The pool to flush
570  * @param BODY The actions to perform on each element before it is returned to
571  * the pool. i.e. before it is 'freed'
572  */
573 #define pool_flush(VAR, POOL, BODY) \
574 { \
575  uword *_pool_var(ii), *_pool_var(dv) = NULL; \
576  \
577  pool_foreach((VAR), (POOL), \
578  ({ \
579  vec_add1(_pool_var(dv), (VAR) - (POOL)); \
580  })); \
581  vec_foreach(_pool_var(ii), _pool_var(dv)) \
582  { \
583  (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
584  do { BODY; } while (0); \
585  pool_put((POOL), (VAR)); \
586  } \
587  vec_free(_pool_var(dv)); \
588 }
589 
590 #endif /* included_pool_h */
591 
592 /*
593  * fd.io coding-style-patch-verification: ON
594  *
595  * Local Variables:
596  * eval: (c-set-style "gnu")
597  * End:
598  */
#define vec_validate(V, I)
Make sure vector is long enough for given index (no header, unspecified alignment) ...
Definition: vec.h:507
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
#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
sll srl srl sll sra u16x4 i
Definition: vector_sse42.h:317
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:380
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:367
#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:65
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