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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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12  * See the License for the specific language governing permissions and
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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
21  without limitation the rights to use, copy, modify, merge, publish,
22  distribute, sublicense, and/or sell copies of the Software, and to
23  permit persons to whom the Software is furnished to do so, subject to
24  the following conditions:
25 
26  The above copyright notice and this permission notice shall be
27  included in all copies or substantial portions of the Software.
28 
29  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
30  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
31  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
32  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
33  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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
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. */
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(P,E,A) \
189 do { \
190  pool_header_t * _pool_var (p) = pool_header (P); \
191  uword _pool_var (l); \
192  \
193  _pool_var (l) = 0; \
194  if (P) \
195  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
196  \
197  if (_pool_var (l) > 0) \
198  { \
199  /* Return free element from free list. */ \
200  uword _pool_var (i) = _pool_var (p)->free_indices[_pool_var (l) - 1]; \
201  (E) = (P) + _pool_var (i); \
202  _pool_var (p)->free_bitmap = \
203  clib_bitmap_andnoti (_pool_var (p)->free_bitmap, _pool_var (i)); \
204  _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
205  } \
206  else \
207  { \
208  /* fixed-size, preallocated pools cannot expand */ \
209  if ((P) && _pool_var(p)->max_elts) \
210  { \
211  clib_warning ("can't expand fixed-size pool"); \
212  os_out_of_memory(); \
213  } \
214  /* Nothing on free list, make a new element and return it. */ \
215  P = _vec_resize (P, \
216  /* length_increment */ 1, \
217  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
218  pool_aligned_header_bytes, \
219  /* align */ (A)); \
220  E = vec_end (P) - 1; \
221  } \
222 } while (0)
223 
224 /** Allocate an object E from a pool P (unspecified alignment). */
225 #define pool_get(P,E) pool_get_aligned(P,E,0)
226 
227 /** See if pool_get will expand the pool or not */
228 #define pool_get_aligned_will_expand(P,YESNO,A) \
229 do { \
230  pool_header_t * _pool_var (p) = pool_header (P); \
231  uword _pool_var (l); \
232  \
233  _pool_var (l) = 0; \
234  if (P) \
235  { \
236  if (_pool_var (p)->max_elts) \
237  return 0; \
238  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
239  } \
240  \
241  /* Free elements, certainly won't expand */ \
242  if (_pool_var (l) > 0) \
243  YESNO=0; \
244  else \
245  { \
246  /* Nothing on free list, make a new element and return it. */ \
247  YESNO = _vec_resize_will_expand \
248  (P, \
249  /* length_increment */ 1, \
250  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
251  pool_aligned_header_bytes, \
252  /* align */ (A)); \
253  } \
254 } while (0)
255 
256 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
257 
258 /** Use free bitmap to query whether given element is free. */
259 #define pool_is_free(P,E) \
260 ({ \
261  pool_header_t * _pool_var (p) = pool_header (P); \
262  uword _pool_var (i) = (E) - (P); \
263  (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
264 })
265 
266 /** Use free bitmap to query whether given index is free */
267 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
268 
269 /** Free an object E in pool P. */
270 #define pool_put(P,E) \
271 do { \
272  pool_header_t * _pool_var (p) = pool_header (P); \
273  uword _pool_var (l) = (E) - (P); \
274  ASSERT (vec_is_member (P, E)); \
275  ASSERT (! pool_is_free (P, E)); \
276  \
277  /* Add element to free bitmap and to free list. */ \
278  _pool_var (p)->free_bitmap = \
279  clib_bitmap_ori (_pool_var (p)->free_bitmap, _pool_var (l)); \
280  /* Preallocated pool? */ \
281  if (_pool_var (p)->max_elts) \
282  { \
283  ASSERT(_pool_var(l) < _pool_var (p)->max_elts); \
284  _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
285  _pool_var(l); \
286  _vec_len(_pool_var(p)->free_indices) += 1; \
287  } \
288  else \
289  vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
290 } while (0)
291 
292 /** Free pool element with given index. */
293 #define pool_put_index(p,i) \
294 do { \
295  typeof (p) _e = (p) + (i); \
296  pool_put (p, _e); \
297 } while (0)
298 
299 /** Allocate N more free elements to pool (general version). */
300 #define pool_alloc_aligned(P,N,A) \
301 do { \
302  pool_header_t * _p; \
303  \
304  if ((P)) \
305  { \
306  _p = pool_header (P); \
307  if (_p->max_elts) \
308  { \
309  clib_warning ("Can't expand fixed-size pool"); \
310  os_out_of_memory(); \
311  } \
312  } \
313  \
314  (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
315  pool_aligned_header_bytes, \
316  (A)); \
317  _p = pool_header (P); \
318  vec_resize (_p->free_indices, (N)); \
319  _vec_len (_p->free_indices) -= (N); \
320 } while (0)
321 
322 /** Allocate N more free elements to pool (unspecified alignment). */
323 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
324 
325 /** Low-level free pool operator (do not call directly). */
326 always_inline void *
327 _pool_free (void *v)
328 {
329  pool_header_t *p = pool_header (v);
330  if (!v)
331  return v;
333 
334  if (p->max_elts)
335  {
336  int rv;
337 
338  rv = munmap (p->mmap_base, p->mmap_size);
339  if (rv)
340  clib_unix_warning ("munmap");
341  }
342  else
343  {
344  vec_free (p->free_indices);
346  }
347  return 0;
348 }
349 
350 /** Free a pool. */
351 #define pool_free(p) (p) = _pool_free(p)
352 
353 /** Optimized iteration through pool.
354 
355  @param LO pointer to first element in chunk
356  @param HI pointer to last element in chunk
357  @param POOL pool to iterate across
358  @param BODY operation to perform
359 
360  Optimized version which assumes that BODY is smart enough to
361  process multiple (LOW,HI) chunks. See also pool_foreach().
362  */
363 #define pool_foreach_region(LO,HI,POOL,BODY) \
364 do { \
365  uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
366  uword _pool_var (bl), * _pool_var (b); \
367  pool_header_t * _pool_var (p); \
368  \
369  _pool_var (p) = pool_header (POOL); \
370  _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
371  _pool_var (bl) = vec_len (_pool_var (b)); \
372  _pool_var (len) = vec_len (POOL); \
373  _pool_var (lo) = 0; \
374  \
375  for (_pool_var (i) = 0; \
376  _pool_var (i) <= _pool_var (bl); \
377  _pool_var (i)++) \
378  { \
379  uword _pool_var (m), _pool_var (f); \
380  _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
381  ? _pool_var (b) [_pool_var (i)] \
382  : 1); \
383  while (_pool_var (m) != 0) \
384  { \
385  _pool_var (f) = first_set (_pool_var (m)); \
386  _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
387  + min_log2 (_pool_var (f))); \
388  _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
389  ? _pool_var (hi) : _pool_var (len)); \
390  _pool_var (m) ^= _pool_var (f); \
391  if (_pool_var (hi) > _pool_var (lo)) \
392  { \
393  (LO) = _pool_var (lo); \
394  (HI) = _pool_var (hi); \
395  do { BODY; } while (0); \
396  } \
397  _pool_var (lo) = _pool_var (hi) + 1; \
398  } \
399  } \
400 } while (0)
401 
402 /** Iterate through pool.
403 
404  @param VAR A variable of same type as pool vector to be used as an
405  iterator.
406  @param POOL The pool to iterate across.
407  @param BODY The operation to perform, typically a code block. See
408  the example below.
409 
410  This macro will call @c BODY with each active pool element.
411 
412  It is a bad idea to allocate or free pool element from within
413  @c pool_foreach. Build a vector of indices and dispose of them later.
414  Or call pool_flush.
415 
416 
417  @par Example
418  @code{.c}
419  proc_t *procs; // a pool of processes.
420  proc_t *proc; // pointer to one process; used as the iterator.
421 
422  pool_foreach (proc, procs, ({
423  if (proc->state != PROC_STATE_RUNNING)
424  continue;
425 
426  // check a running proc in some way
427  ...
428  }));
429  @endcode
430 
431  @warning Because @c pool_foreach is a macro, syntax errors can be
432  difficult to find inside @c BODY, let alone actual code bugs. One
433  can temporarily split a complex @c pool_foreach into a trivial
434  @c pool_foreach which builds a vector of active indices, and a
435  vec_foreach() (or plain for-loop) to walk the active index vector.
436  */
437 #define pool_foreach(VAR,POOL,BODY) \
438 do { \
439  uword _pool_foreach_lo, _pool_foreach_hi; \
440  pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
441  ({ \
442  for ((VAR) = (POOL) + _pool_foreach_lo; \
443  (VAR) < (POOL) + _pool_foreach_hi; \
444  (VAR)++) \
445  do { BODY; } while (0); \
446  })); \
447 } while (0)
448 
449 /** Returns pointer to element at given index.
450 
451  ASSERTs that the supplied index is valid.
452  Even though one can write correct code of the form
453  @code
454  p = pool_base + index;
455  @endcode
456  use of @c pool_elt_at_index is strongly suggested.
457  */
458 #define pool_elt_at_index(p,i) \
459 ({ \
460  typeof (p) _e = (p) + (i); \
461  ASSERT (! pool_is_free (p, _e)); \
462  _e; \
463 })
464 
465 /** Return next occupied pool index after @c i, useful for safe iteration. */
466 #define pool_next_index(P,I) \
467 ({ \
468  pool_header_t * _pool_var (p) = pool_header (P); \
469  uword _pool_var (rv) = (I) + 1; \
470  \
471  _pool_var(rv) = \
472  (_pool_var (rv) < vec_len (P) ? \
473  clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
474  : ~0); \
475  _pool_var(rv); \
476 })
477 
478 /** Iterate pool by index. */
479 #define pool_foreach_index(i,v,body) \
480  for ((i) = 0; (i) < vec_len (v); (i)++) \
481  { \
482  if (! pool_is_free_index ((v), (i))) \
483  do { body; } while (0); \
484  }
485 
486 /**
487  * @brief Remove all elemenets from a pool in a safe way
488  *
489  * @param VAR each element in the pool
490  * @param POOL The pool to flush
491  * @param BODY The actions to perform on each element before it is returned to
492  * the pool. i.e. before it is 'freed'
493  */
494 #define pool_flush(VAR, POOL, BODY) \
495 { \
496  uword *_pool_var(ii), *_pool_var(dv) = NULL; \
497  \
498  pool_foreach((VAR), (POOL), \
499  ({ \
500  vec_add1(_pool_var(dv), (VAR) - (POOL)); \
501  })); \
502  vec_foreach(_pool_var(ii), _pool_var(dv)) \
503  { \
504  (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
505  do { BODY; } while (0); \
506  pool_put((POOL), (VAR)); \
507  } \
508  vec_free(_pool_var(dv)); \
509 }
510 
511 #endif /* included_pool_h */
512 
513 /*
514  * fd.io coding-style-patch-verification: ON
515  *
516  * Local Variables:
517  * eval: (c-set-style "gnu")
518  * End:
519  */
#define vec_validate(V, I)
Make sure vector is long enough for given index (no header, unspecified alignment) ...
Definition: vec.h:432
sll srl srl sll sra u16x4 i
Definition: vector_sse2.h:337
u64 mmap_size
Definition: pool.h:67
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.
#define always_inline
Definition: clib.h:84
unsigned long u64
Definition: types.h:89
void fpool_free(void *)
static pool_header_t * pool_header(void *v)
Get pool header from user pool pointer.
Definition: pool.h:77
#define v
Definition: acl.c:323
#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:336
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)
unsigned int u32
Definition: types.h:88
Bitmaps built as vectors of machine words.
#define clib_bitmap_free(v)
Free a bitmap.
Definition: bitmap.h:92
u64 uword
Definition: types.h:112
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:441
#define vec_free_h(V, H)
Free vector&#39;s memory (general version)
Definition: vec.h:323
#define vec_len(v)
Number of elements in vector (rvalue-only, NULL tolerant)
unsigned char u8
Definition: types.h:56
#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:58
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