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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:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
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12  * See the License for the specific language governing permissions and
13  * limitations under the License.
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  _pool_var (l) = _pool_var (p)->max_elts; \
238  else \
239  _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
240  } \
241  \
242  /* Free elements, certainly won't expand */ \
243  if (_pool_var (l) > 0) \
244  YESNO=0; \
245  else \
246  { \
247  /* Nothing on free list, make a new element and return it. */ \
248  YESNO = _vec_resize_will_expand \
249  (P, \
250  /* length_increment */ 1, \
251  /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
252  pool_aligned_header_bytes, \
253  /* align */ (A)); \
254  } \
255 } while (0)
256 
257 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
258 
259 /** Use free bitmap to query whether given element is free. */
260 #define pool_is_free(P,E) \
261 ({ \
262  pool_header_t * _pool_var (p) = pool_header (P); \
263  uword _pool_var (i) = (E) - (P); \
264  (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
265 })
266 
267 /** Use free bitmap to query whether given index is free */
268 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
269 
270 /** Free an object E in pool P. */
271 #define pool_put(P,E) \
272 do { \
273  pool_header_t * _pool_var (p) = pool_header (P); \
274  uword _pool_var (l) = (E) - (P); \
275  ASSERT (vec_is_member (P, E)); \
276  ASSERT (! pool_is_free (P, E)); \
277  \
278  /* Add element to free bitmap and to free list. */ \
279  _pool_var (p)->free_bitmap = \
280  clib_bitmap_ori (_pool_var (p)->free_bitmap, _pool_var (l)); \
281  /* Preallocated pool? */ \
282  if (_pool_var (p)->max_elts) \
283  { \
284  ASSERT(_pool_var(l) < _pool_var (p)->max_elts); \
285  _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
286  _pool_var(l); \
287  _vec_len(_pool_var(p)->free_indices) += 1; \
288  } \
289  else \
290  vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
291 } while (0)
292 
293 /** Free pool element with given index. */
294 #define pool_put_index(p,i) \
295 do { \
296  typeof (p) _e = (p) + (i); \
297  pool_put (p, _e); \
298 } while (0)
299 
300 /** Allocate N more free elements to pool (general version). */
301 #define pool_alloc_aligned(P,N,A) \
302 do { \
303  pool_header_t * _p; \
304  \
305  if ((P)) \
306  { \
307  _p = pool_header (P); \
308  if (_p->max_elts) \
309  { \
310  clib_warning ("Can't expand fixed-size pool"); \
311  os_out_of_memory(); \
312  } \
313  } \
314  \
315  (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
316  pool_aligned_header_bytes, \
317  (A)); \
318  _p = pool_header (P); \
319  vec_resize (_p->free_indices, (N)); \
320  _vec_len (_p->free_indices) -= (N); \
321 } while (0)
322 
323 /** Allocate N more free elements to pool (unspecified alignment). */
324 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
325 
326 /** Low-level free pool operator (do not call directly). */
327 always_inline void *
328 _pool_free (void *v)
329 {
330  pool_header_t *p = pool_header (v);
331  if (!v)
332  return v;
334 
335  if (p->max_elts)
336  {
337  int rv;
338 
339  rv = munmap (p->mmap_base, p->mmap_size);
340  if (rv)
341  clib_unix_warning ("munmap");
342  }
343  else
344  {
345  vec_free (p->free_indices);
347  }
348  return 0;
349 }
350 
351 /** Free a pool. */
352 #define pool_free(p) (p) = _pool_free(p)
353 
354 /** Optimized iteration through pool.
355 
356  @param LO pointer to first element in chunk
357  @param HI pointer to last element in chunk
358  @param POOL pool to iterate across
359  @param BODY operation to perform
360 
361  Optimized version which assumes that BODY is smart enough to
362  process multiple (LOW,HI) chunks. See also pool_foreach().
363  */
364 #define pool_foreach_region(LO,HI,POOL,BODY) \
365 do { \
366  uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
367  uword _pool_var (bl), * _pool_var (b); \
368  pool_header_t * _pool_var (p); \
369  \
370  _pool_var (p) = pool_header (POOL); \
371  _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
372  _pool_var (bl) = vec_len (_pool_var (b)); \
373  _pool_var (len) = vec_len (POOL); \
374  _pool_var (lo) = 0; \
375  \
376  for (_pool_var (i) = 0; \
377  _pool_var (i) <= _pool_var (bl); \
378  _pool_var (i)++) \
379  { \
380  uword _pool_var (m), _pool_var (f); \
381  _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
382  ? _pool_var (b) [_pool_var (i)] \
383  : 1); \
384  while (_pool_var (m) != 0) \
385  { \
386  _pool_var (f) = first_set (_pool_var (m)); \
387  _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
388  + min_log2 (_pool_var (f))); \
389  _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
390  ? _pool_var (hi) : _pool_var (len)); \
391  _pool_var (m) ^= _pool_var (f); \
392  if (_pool_var (hi) > _pool_var (lo)) \
393  { \
394  (LO) = _pool_var (lo); \
395  (HI) = _pool_var (hi); \
396  do { BODY; } while (0); \
397  } \
398  _pool_var (lo) = _pool_var (hi) + 1; \
399  } \
400  } \
401 } while (0)
402 
403 /** Iterate through pool.
404 
405  @param VAR A variable of same type as pool vector to be used as an
406  iterator.
407  @param POOL The pool to iterate across.
408  @param BODY The operation to perform, typically a code block. See
409  the example below.
410 
411  This macro will call @c BODY with each active pool element.
412 
413  It is a bad idea to allocate or free pool element from within
414  @c pool_foreach. Build a vector of indices and dispose of them later.
415  Or call pool_flush.
416 
417 
418  @par Example
419  @code{.c}
420  proc_t *procs; // a pool of processes.
421  proc_t *proc; // pointer to one process; used as the iterator.
422 
423  pool_foreach (proc, procs, ({
424  if (proc->state != PROC_STATE_RUNNING)
425  continue;
426 
427  // check a running proc in some way
428  ...
429  }));
430  @endcode
431 
432  @warning Because @c pool_foreach is a macro, syntax errors can be
433  difficult to find inside @c BODY, let alone actual code bugs. One
434  can temporarily split a complex @c pool_foreach into a trivial
435  @c pool_foreach which builds a vector of active indices, and a
436  vec_foreach() (or plain for-loop) to walk the active index vector.
437  */
438 #define pool_foreach(VAR,POOL,BODY) \
439 do { \
440  uword _pool_foreach_lo, _pool_foreach_hi; \
441  pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
442  ({ \
443  for ((VAR) = (POOL) + _pool_foreach_lo; \
444  (VAR) < (POOL) + _pool_foreach_hi; \
445  (VAR)++) \
446  do { BODY; } while (0); \
447  })); \
448 } while (0)
449 
450 /** Returns pointer to element at given index.
451 
452  ASSERTs that the supplied index is valid.
453  Even though one can write correct code of the form
454  @code
455  p = pool_base + index;
456  @endcode
457  use of @c pool_elt_at_index is strongly suggested.
458  */
459 #define pool_elt_at_index(p,i) \
460 ({ \
461  typeof (p) _e = (p) + (i); \
462  ASSERT (! pool_is_free (p, _e)); \
463  _e; \
464 })
465 
466 /** Return next occupied pool index after @c i, useful for safe iteration. */
467 #define pool_next_index(P,I) \
468 ({ \
469  pool_header_t * _pool_var (p) = pool_header (P); \
470  uword _pool_var (rv) = (I) + 1; \
471  \
472  _pool_var(rv) = \
473  (_pool_var (rv) < vec_len (P) ? \
474  clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
475  : ~0); \
476  _pool_var(rv); \
477 })
478 
479 /** Iterate pool by index. */
480 #define pool_foreach_index(i,v,body) \
481  for ((i) = 0; (i) < vec_len (v); (i)++) \
482  { \
483  if (! pool_is_free_index ((v), (i))) \
484  do { body; } while (0); \
485  }
486 
487 /**
488  * @brief Remove all elemenets from a pool in a safe way
489  *
490  * @param VAR each element in the pool
491  * @param POOL The pool to flush
492  * @param BODY The actions to perform on each element before it is returned to
493  * the pool. i.e. before it is 'freed'
494  */
495 #define pool_flush(VAR, POOL, BODY) \
496 { \
497  uword *_pool_var(ii), *_pool_var(dv) = NULL; \
498  \
499  pool_foreach((VAR), (POOL), \
500  ({ \
501  vec_add1(_pool_var(dv), (VAR) - (POOL)); \
502  })); \
503  vec_foreach(_pool_var(ii), _pool_var(dv)) \
504  { \
505  (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
506  do { BODY; } while (0); \
507  pool_put((POOL), (VAR)); \
508  } \
509  vec_free(_pool_var(dv)); \
510 }
511 
512 #endif /* included_pool_h */
513 
514 /*
515  * fd.io coding-style-patch-verification: ON
516  *
517  * Local Variables:
518  * eval: (c-set-style "gnu")
519  * End:
520  */
#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:92
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:341
#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