FD.io VPP  v21.01.1
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
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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 
50 
51 typedef struct
52 {
53  /** Bitmap of indices of free objects. */
55 
56  /** Vector of free indices. One element for each set bit in bitmap. */
58 
59  /* The following fields are set for fixed-size, preallocated pools */
60 
61  /** Maximum size of the pool, in elements */
63 
64  /** mmap segment info: base + length */
67 
69 
70 /** Align pool header so that pointers are naturally aligned. */
71 #define pool_aligned_header_bytes \
72  vec_aligned_header_bytes (sizeof (pool_header_t), sizeof (void *))
73 
74 /** Get pool header from user pool pointer */
76 pool_header (void *v)
77 {
78  return vec_aligned_header (v, sizeof (pool_header_t), sizeof (void *));
79 }
80 
81 extern void _pool_init_fixed (void **, u32, u32);
82 extern void fpool_free (void *);
83 
84 /** initialize a fixed-size, preallocated pool */
85 #define pool_init_fixed(pool,max_elts) \
86 { \
87  _pool_init_fixed((void **)&(pool),sizeof(pool[0]),max_elts); \
88 }
89 
90 /** Validate a pool */
91 always_inline void
92 pool_validate (void *v)
93 {
94  pool_header_t *p = pool_header (v);
95  uword i, n_free_bitmap;
96 
97  if (!v)
98  return;
99 
100  n_free_bitmap = clib_bitmap_count_set_bits (p->free_bitmap);
101  ASSERT (n_free_bitmap == vec_len (p->free_indices));
102  for (i = 0; i < vec_len (p->free_indices); i++)
103  ASSERT (clib_bitmap_get (p->free_bitmap, p->free_indices[i]) == 1);
104 }
105 
106 always_inline void
108 {
109  pool_header_t *p = pool_header (v);
110 
111  if (v)
112  vec_validate (p->free_bitmap, index / BITS (uword));
113 }
114 
115 #define pool_validate_index(v,i) \
116 do { \
117  uword __pool_validate_index = (i); \
118  vec_validate_ha ((v), __pool_validate_index, \
119  pool_aligned_header_bytes, /* align */ 0); \
120  pool_header_validate_index ((v), __pool_validate_index); \
121 } while (0)
122 
123 /** Number of active elements in a pool.
124  * @return Number of active elements in a pool
125  */
127 pool_elts (void *v)
128 {
129  uword ret = vec_len (v);
130  if (v)
131  ret -= vec_len (pool_header (v)->free_indices);
132  return ret;
133 }
134 
135 /** Number of elements in pool vector.
136 
137  @note You probably want to call pool_elts() instead.
138 */
139 #define pool_len(p) vec_len(p)
140 
141 /** Number of elements in pool vector (usable as an lvalue)
142 
143  @note You probably don't want to use this macro.
144 */
145 #define _pool_len(p) _vec_len(p)
146 
147 /** Memory usage of pool header. */
150 {
151  pool_header_t *p = pool_header (v);
152 
153  if (!v)
154  return 0;
155 
156  return vec_bytes (p->free_bitmap) + vec_bytes (p->free_indices);
157 }
158 
159 /** Memory usage of pool. */
160 #define pool_bytes(P) (vec_bytes (P) + pool_header_bytes (P))
161 
162 /** Local variable naming macro. */
163 #define _pool_var(v) _pool_##v
164 
165 /** Queries whether pool has at least N_FREE free elements. */
167 pool_free_elts (void *v)
168 {
169  pool_header_t *p = pool_header (v);
170  uword n_free = 0;
171 
172  if (v)
173  {
174  n_free += vec_len (p->free_indices);
175 
176  /* Space left at end of vector? */
177  n_free += vec_capacity (v, sizeof (p[0])) - vec_len (v);
178  }
179 
180  return n_free;
181 }
182 
183 /** Allocate an object E from a pool P (general version).
184 
185  First search free list. If nothing is free extend vector of objects.
186 */
187 #define _pool_get_aligned_internal_numa(P,E,A,Z,N) \
188 do { \
189  pool_header_t * _pool_var (p) = pool_header (P); \
190  uword _pool_var (l); \
191  \
192  STATIC_ASSERT(A==0 || ((A % sizeof(P[0]))==0) \
193  || ((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) = \
203  _pool_var (p)->free_indices[_pool_var (l) - 1]; \
204  (E) = (P) + _pool_var (i); \
205  _pool_var (p)->free_bitmap = \
206  clib_bitmap_andnoti_notrim (_pool_var (p)->free_bitmap, \
207  _pool_var (i)); \
208  _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
209  CLIB_MEM_UNPOISON((E), sizeof((E)[0])); \
210  } \
211  else \
212  { \
213  /* fixed-size, preallocated pools cannot expand */ \
214  if ((P) && _pool_var(p)->max_elts) \
215  { \
216  clib_warning ("can't expand fixed-size pool"); \
217  os_out_of_memory(); \
218  } \
219  /* Nothing on free list, make a new element and return it. */ \
220  P = _vec_resize_numa (P, \
221  /* length_increment */ 1, \
222  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
223  pool_aligned_header_bytes, \
224  /* align */ (A), \
225  /* numa */ (N)); \
226  E = vec_end (P) - 1; \
227  } \
228  if (Z) \
229  memset(E, 0, sizeof(*E)); \
230 } while (0)
231 
232 #define pool_get_aligned_zero_numa(P,E,A,Z,S) \
233  _pool_get_aligned_internal_numa(P,E,A,Z,S)
234 
235 #define pool_get_aligned_numa(P,E,A,S) \
236  _pool_get_aligned_internal_numa(P,E,A,0/*zero*/,S)
237 
238 #define pool_get_numa(P,E,S) \
239  _pool_get_aligned_internal_numa(P,E,0/*align*/,0/*zero*/,S)
240 
241 #define _pool_get_aligned_internal(P,E,A,Z) \
242  _pool_get_aligned_internal_numa(P,E,A,Z,VEC_NUMA_UNSPECIFIED)
243 
244 /** Allocate an object E from a pool P with alignment A */
245 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
246 
247 /** Allocate an object E from a pool P with alignment A and zero it */
248 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
249 
250 /** Allocate an object E from a pool P (unspecified alignment). */
251 #define pool_get(P,E) pool_get_aligned(P,E,0)
252 
253 /** Allocate an object E from a pool P and zero it */
254 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
255 
256 /** See if pool_get will expand the pool or not */
257 #define pool_get_aligned_will_expand(P,YESNO,A) \
258 do { \
259  pool_header_t * _pool_var (p) = pool_header (P); \
260  uword _pool_var (l); \
261  \
262  _pool_var (l) = 0; \
263  if (P) \
264  { \
265  if (_pool_var (p)->max_elts) \
266  _pool_var (l) = _pool_var (p)->max_elts; \
267  else \
268  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
269  } \
270  \
271  /* Free elements, certainly won't expand */ \
272  if (_pool_var (l) > 0) \
273  YESNO=0; \
274  else \
275  { \
276  /* Nothing on free list, make a new element and return it. */ \
277  YESNO = _vec_resize_will_expand \
278  (P, \
279  /* length_increment */ 1, \
280  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
281  pool_aligned_header_bytes, \
282  /* align */ (A)); \
283  } \
284 } while (0)
285 
286 /** Tell the caller if pool get will expand the pool */
287 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
288 
289 /** Use free bitmap to query whether given element is free. */
290 #define pool_is_free(P,E) \
291 ({ \
292  pool_header_t * _pool_var (p) = pool_header (P); \
293  uword _pool_var (i) = (E) - (P); \
294  (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
295 })
296 
297 /** Use free bitmap to query whether given index is free */
298 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
299 
300 /** Free an object E in pool P. */
301 #define pool_put(P,E) \
302 do { \
303  typeof (P) _pool_var(p__) = (P); \
304  typeof (E) _pool_var(e__) = (E); \
305  pool_header_t * _pool_var (p) = pool_header (_pool_var(p__)); \
306  uword _pool_var (l) = _pool_var(e__) - _pool_var(p__); \
307  ASSERT (vec_is_member (_pool_var(p__), _pool_var(e__))); \
308  ASSERT (! pool_is_free (_pool_var(p__), _pool_var(e__))); \
309  \
310  /* Add element to free bitmap and to free list. */ \
311  _pool_var (p)->free_bitmap = \
312  clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap, \
313  _pool_var (l)); \
314  \
315  /* Preallocated pool? */ \
316  if (_pool_var (p)->max_elts) \
317  { \
318  ASSERT(_pool_var(l) < _pool_var (p)->max_elts); \
319  _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
320  _pool_var(l); \
321  _vec_len(_pool_var(p)->free_indices) += 1; \
322  } \
323  else \
324  vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
325  \
326  CLIB_MEM_POISON(_pool_var(e__), sizeof(_pool_var(e__)[0])); \
327 } while (0)
328 
329 /** Free pool element with given index. */
330 #define pool_put_index(p,i) \
331 do { \
332  typeof (p) _e = (p) + (i); \
333  pool_put (p, _e); \
334 } while (0)
335 
336 /** Allocate N more free elements to pool (general version). */
337 #define pool_alloc_aligned(P,N,A) \
338 do { \
339  pool_header_t * _p; \
340  \
341  if ((P)) \
342  { \
343  _p = pool_header (P); \
344  if (_p->max_elts) \
345  { \
346  clib_warning ("Can't expand fixed-size pool"); \
347  os_out_of_memory(); \
348  } \
349  } \
350  \
351  (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
352  pool_aligned_header_bytes, \
353  (A)); \
354  _p = pool_header (P); \
355  vec_resize (_p->free_indices, (N)); \
356  _vec_len (_p->free_indices) -= (N); \
357 } while (0)
358 
359 /** Allocate N more free elements to pool (unspecified alignment). */
360 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
361 
362 /**
363  * Return copy of pool with alignment
364  *
365  * @param P pool to copy
366  * @param A alignment (may be zero)
367  * @return copy of pool
368  */
369 #define pool_dup_aligned(P,A) \
370 ({ \
371  typeof (P) _pool_var (new) = 0; \
372  pool_header_t * _pool_var (ph), * _pool_var (new_ph); \
373  u32 _pool_var (n) = pool_len (P); \
374  if ((P)) \
375  { \
376  _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n), \
377  _pool_var (n) * sizeof ((P)[0]), \
378  pool_aligned_header_bytes, (A)); \
379  clib_memcpy_fast (_pool_var (new), (P), \
380  _pool_var (n) * sizeof ((P)[0])); \
381  _pool_var (ph) = pool_header (P); \
382  _pool_var (new_ph) = pool_header (_pool_var (new)); \
383  _pool_var (new_ph)->free_bitmap = \
384  clib_bitmap_dup (_pool_var (ph)->free_bitmap); \
385  _pool_var (new_ph)->free_indices = \
386  vec_dup (_pool_var (ph)->free_indices); \
387  _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts; \
388  } \
389  _pool_var (new); \
390 })
391 
392 /**
393  * Return copy of pool without alignment
394  *
395  * @param P pool to copy
396  * @return copy of pool
397  */
398 #define pool_dup(P) pool_dup_aligned(P,0)
399 
400 /** Low-level free pool operator (do not call directly). */
401 always_inline void *
402 _pool_free (void *v)
403 {
404  pool_header_t *p = pool_header (v);
405  if (!v)
406  return v;
408 
409  if (p->max_elts)
410  {
411  int rv;
412 
413  rv = munmap (p->mmap_base, p->mmap_size);
414  if (rv)
415  clib_unix_warning ("munmap");
416  }
417  else
418  {
419  vec_free (p->free_indices);
421  }
422  return 0;
423 }
424 
427 {
428  pool_header_t *h = pool_header (pool);
430 }
431 
434 {
435  pool_header_t *h = pool_header (pool);
436  return clib_bitmap_next_clear (h->free_bitmap, last + 1);
437 }
438 
439 /** Free a pool. */
440 #define pool_free(p) (p) = _pool_free(p)
441 
442 /** Optimized iteration through pool.
443 
444  @param LO pointer to first element in chunk
445  @param HI pointer to last element in chunk
446  @param POOL pool to iterate across
447  @param BODY operation to perform
448 
449  Optimized version which assumes that BODY is smart enough to
450  process multiple (LOW,HI) chunks. See also pool_foreach().
451  */
452 #define pool_foreach_region(LO,HI,POOL,BODY) \
453 do { \
454  uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
455  uword _pool_var (bl), * _pool_var (b); \
456  pool_header_t * _pool_var (p); \
457  \
458  _pool_var (p) = pool_header (POOL); \
459  _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
460  _pool_var (bl) = vec_len (_pool_var (b)); \
461  _pool_var (len) = vec_len (POOL); \
462  _pool_var (lo) = 0; \
463  \
464  for (_pool_var (i) = 0; \
465  _pool_var (i) <= _pool_var (bl); \
466  _pool_var (i)++) \
467  { \
468  uword _pool_var (m), _pool_var (f); \
469  _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
470  ? _pool_var (b) [_pool_var (i)] \
471  : 1); \
472  while (_pool_var (m) != 0) \
473  { \
474  _pool_var (f) = first_set (_pool_var (m)); \
475  _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
476  + min_log2 (_pool_var (f))); \
477  _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
478  ? _pool_var (hi) : _pool_var (len)); \
479  _pool_var (m) ^= _pool_var (f); \
480  if (_pool_var (hi) > _pool_var (lo)) \
481  { \
482  (LO) = _pool_var (lo); \
483  (HI) = _pool_var (hi); \
484  do { BODY; } while (0); \
485  } \
486  _pool_var (lo) = _pool_var (hi) + 1; \
487  } \
488  } \
489 } while (0)
490 
491 /** Iterate through pool.
492 
493  @param VAR A variable of same type as pool vector to be used as an
494  iterator.
495  @param POOL The pool to iterate across.
496  @param BODY The operation to perform, typically a code block. See
497  the example below.
498 
499  This macro will call @c BODY with each active pool element.
500 
501  It is a bad idea to allocate or free pool element from within
502  @c pool_foreach. Build a vector of indices and dispose of them later.
503  Or call pool_flush.
504 
505 
506  @par Example
507  @code{.c}
508  proc_t *procs; // a pool of processes.
509  proc_t *proc; // pointer to one process; used as the iterator.
510 
511  pool_foreach (proc, procs, ({
512  if (proc->state != PROC_STATE_RUNNING)
513  continue;
514 
515  // check a running proc in some way
516  ...
517  }));
518  @endcode
519 
520  @warning Because @c pool_foreach is a macro, syntax errors can be
521  difficult to find inside @c BODY, let alone actual code bugs. One
522  can temporarily split a complex @c pool_foreach into a trivial
523  @c pool_foreach which builds a vector of active indices, and a
524  vec_foreach() (or plain for-loop) to walk the active index vector.
525  */
526 
527 #define pool_foreach(VAR,POOL) \
528  if (POOL) \
529  for (VAR = POOL + pool_get_first_index (POOL); \
530  VAR < vec_end (POOL); \
531  VAR = POOL + pool_get_next_index (POOL, VAR - POOL))
532 
533 #define pool_foreach_old(VAR,POOL,BODY) \
534  pool_foreach(VAR,POOL) \
535  { BODY; }
536 
537 /** Returns pointer to element at given index.
538 
539  ASSERTs that the supplied index is valid.
540  Even though one can write correct code of the form
541  @code
542  p = pool_base + index;
543  @endcode
544  use of @c pool_elt_at_index is strongly suggested.
545  */
546 #define pool_elt_at_index(p,i) \
547 ({ \
548  typeof (p) _e = (p) + (i); \
549  ASSERT (! pool_is_free (p, _e)); \
550  _e; \
551 })
552 
553 /** Return next occupied pool index after @c i, useful for safe iteration. */
554 #define pool_next_index(P,I) \
555 ({ \
556  pool_header_t * _pool_var (p) = pool_header (P); \
557  uword _pool_var (rv) = (I) + 1; \
558  \
559  _pool_var(rv) = \
560  (_pool_var (rv) < vec_len (P) ? \
561  clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
562  : ~0); \
563  _pool_var(rv) = \
564  (_pool_var (rv) < vec_len (P) ? \
565  _pool_var (rv) : ~0); \
566  _pool_var(rv); \
567 })
568 
569 #define pool_foreach_index(i,v) \
570  if (v) \
571  for (i = pool_get_first_index (v); \
572  i < vec_len (v); \
573  i = pool_get_next_index (v, i)) \
574 
575 /** Iterate pool by index. */
576 #define pool_foreach_index_old(i,v,body) \
577  pool_foreach_index (i,v) \
578  { body; }
579 
580 /**
581  * @brief Remove all elements from a pool in a safe way
582  *
583  * @param VAR each element in the pool
584  * @param POOL The pool to flush
585  * @param BODY The actions to perform on each element before it is returned to
586  * the pool. i.e. before it is 'freed'
587  */
588 #define pool_flush(VAR, POOL, BODY) \
589 { \
590  uword *_pool_var(ii), *_pool_var(dv) = NULL; \
591  \
592  pool_foreach((VAR), (POOL)) \
593  { \
594  vec_add1(_pool_var(dv), (VAR) - (POOL)); \
595  } \
596  vec_foreach(_pool_var(ii), _pool_var(dv)) \
597  { \
598  (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
599  do { BODY; } while (0); \
600  pool_put((POOL), (VAR)); \
601  } \
602  vec_free(_pool_var(dv)); \
603 }
604 
605 #endif /* included_pool_h */
606 
607 /*
608  * fd.io coding-style-patch-verification: ON
609  *
610  * Local Variables:
611  * eval: (c-set-style "gnu")
612  * End:
613  */
#define vec_validate(V, I)
Make sure vector is long enough for given index (no header, unspecified alignment) ...
Definition: vec.h:509
static_always_inline uword pool_get_first_index(void *pool)
Definition: pool.h:426
u64 mmap_size
Definition: pool.h:66
unsigned long u64
Definition: types.h:89
static void pool_header_validate_index(void *v, uword index)
Definition: pool.h:107
u32 * free_indices
Vector of free indices.
Definition: pool.h:57
static heap_elt_t * last(heap_header_t *h)
Definition: heap.c:53
#define vec_bytes(v)
Number of data bytes in vector.
unsigned char u8
Definition: types.h:56
#define static_always_inline
Definition: clib.h:109
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:76
vec_header_t h
Definition: buffer.c:322
#define always_inline
Definition: ipsec.h:28
static_always_inline uword pool_get_next_index(void *pool, uword last)
Definition: pool.h:433
#define pool_aligned_header_bytes
Align pool header so that pointers are naturally aligned.
Definition: pool.h:71
static uword pool_header_bytes(void *v)
Memory usage of pool header.
Definition: pool.h:149
sll srl srl sll sra u16x4 i
Definition: vector_sse42.h:317
static void pool_validate(void *v)
Validate a pool.
Definition: pool.h:92
#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:54
static uword clib_bitmap_count_set_bits(uword *ai)
Return the number of set bits in a bitmap.
Definition: bitmap.h:468
#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 index
Definition: flow_types.api:221
u32 max_elts
Maximum size of the pool, in elements.
Definition: pool.h:62
static uword clib_bitmap_first_clear(uword *ai)
Return the lowest numbered clear bit in a bitmap.
Definition: bitmap.h:451
#define BITS(x)
Definition: clib.h:66
static uword pool_free_elts(void *v)
Queries whether pool has at least N_FREE free elements.
Definition: pool.h:167
u8 * mmap_base
mmap segment info: base + length
Definition: pool.h:65
static uword pool_elts(void *v)
Number of active elements in a pool.
Definition: pool.h:127