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:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 Copyright (c) 2001, 2002, 2003, 2004 Eliot Dresselhaus
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:
26 The above copyright notice and this permission notice shall be
27 included in all copies or substantial portions of the Software.
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.
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.
44 #ifndef included_pool_h
45 #define included_pool_h
47 #include <vppinfra/bitmap.h>
48 #include <vppinfra/error.h>
49 #include <vppinfra/mheap.h>
54 /** Bitmap of indices of free objects. */
57 /** Vector of free indices. One element for each set bit in bitmap. */
61 /** Align pool header so that pointers are naturally aligned. */
62 #define pool_aligned_header_bytes \
63 vec_aligned_header_bytes (sizeof (pool_header_t), sizeof (void *))
65 /** Get pool header from user pool pointer */
66 always_inline pool_header_t *
69 return vec_aligned_header (v, sizeof (pool_header_t), sizeof (void *));
72 /** Validate a pool */
74 pool_validate (void *v)
76 pool_header_t *p = pool_header (v);
77 uword i, n_free_bitmap;
82 n_free_bitmap = clib_bitmap_count_set_bits (p->free_bitmap);
83 ASSERT (n_free_bitmap == vec_len (p->free_indices));
84 for (i = 0; i < vec_len (p->free_indices); i++)
85 ASSERT (clib_bitmap_get (p->free_bitmap, p->free_indices[i]) == 1);
89 pool_header_validate_index (void *v, uword index)
91 pool_header_t *p = pool_header (v);
94 vec_validate (p->free_bitmap, index / BITS (uword));
97 #define pool_validate_index(v,i) \
99 uword __pool_validate_index = (i); \
100 vec_validate_ha ((v), __pool_validate_index, \
101 pool_aligned_header_bytes, /* align */ 0); \
102 pool_header_validate_index ((v), __pool_validate_index); \
105 /** Number of active elements in a pool.
106 * @return Number of active elements in a pool
111 uword ret = vec_len (v);
113 ret -= vec_len (pool_header (v)->free_indices);
117 /** Number of elements in pool vector.
119 @note You probably want to call pool_elts() instead.
121 #define pool_len(p) vec_len(p)
123 /** Number of elements in pool vector (usable as an lvalue)
125 @note You probably don't want to use this macro.
127 #define _pool_len(p) _vec_len(p)
129 /** Memory usage of pool header. */
131 pool_header_bytes (void *v)
133 pool_header_t *p = pool_header (v);
138 return vec_bytes (p->free_bitmap) + vec_bytes (p->free_indices);
141 /** Memory usage of pool. */
142 #define pool_bytes(P) (vec_bytes (P) + pool_header_bytes (P))
144 /** Local variable naming macro. */
145 #define _pool_var(v) _pool_##v
147 /** Queries whether pool has at least N_FREE free elements. */
149 pool_free_elts (void *v)
151 pool_header_t *p = pool_header (v);
156 n_free += vec_len (p->free_indices);
158 /* Space left at end of vector? */
159 n_free += vec_capacity (v, sizeof (p[0])) - vec_len (v);
165 /** Allocate an object E from a pool P (general version).
167 First search free list. If nothing is free extend vector of objects.
169 #define pool_get_aligned(P,E,A) \
171 pool_header_t * _pool_var (p) = pool_header (P); \
172 uword _pool_var (l); \
176 _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
178 if (_pool_var (l) > 0) \
180 /* Return free element from free list. */ \
181 uword _pool_var (i) = _pool_var (p)->free_indices[_pool_var (l) - 1]; \
182 (E) = (P) + _pool_var (i); \
183 _pool_var (p)->free_bitmap = \
184 clib_bitmap_andnoti (_pool_var (p)->free_bitmap, _pool_var (i)); \
185 _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
189 /* Nothing on free list, make a new element and return it. */ \
190 P = _vec_resize (P, \
191 /* length_increment */ 1, \
192 /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
193 pool_aligned_header_bytes, \
195 E = vec_end (P) - 1; \
199 /** Allocate an object E from a pool P (unspecified alignment). */
200 #define pool_get(P,E) pool_get_aligned(P,E,0)
202 /** See if pool_get will expand the pool or not */
203 #define pool_get_aligned_will_expand (P,YESNO,A) \
205 pool_header_t * _pool_var (p) = pool_header (P); \
206 uword _pool_var (l); \
210 _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
212 /* Free elements, certainly won't expand */ \
213 if (_pool_var (l) > 0) \
217 /* Nothing on free list, make a new element and return it. */ \
218 YESNO = _vec_resize_will_expand \
220 /* length_increment */ 1, \
221 /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
222 pool_aligned_header_bytes, \
227 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
229 /** Use free bitmap to query whether given element is free. */
230 #define pool_is_free(P,E) \
232 pool_header_t * _pool_var (p) = pool_header (P); \
233 uword _pool_var (i) = (E) - (P); \
234 (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
237 /** Use free bitmap to query whether given index is free */
238 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
240 /** Free an object E in pool P. */
241 #define pool_put(P,E) \
243 pool_header_t * _pool_var (p) = pool_header (P); \
244 uword _pool_var (l) = (E) - (P); \
245 ASSERT (vec_is_member (P, E)); \
246 ASSERT (! pool_is_free (P, E)); \
248 /* Add element to free bitmap and to free list. */ \
249 _pool_var (p)->free_bitmap = \
250 clib_bitmap_ori (_pool_var (p)->free_bitmap, _pool_var (l)); \
251 vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
254 /** Free pool element with given index. */
255 #define pool_put_index(p,i) \
257 typeof (p) _e = (p) + (i); \
261 /** Allocate N more free elements to pool (general version). */
262 #define pool_alloc_aligned(P,N,A) \
264 pool_header_t * _p; \
265 (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
266 pool_aligned_header_bytes, \
268 _p = pool_header (P); \
269 vec_resize (_p->free_indices, (N)); \
270 _vec_len (_p->free_indices) -= (N); \
273 /** Allocate N more free elements to pool (unspecified alignment). */
274 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
276 /** Low-level free pool operator (do not call directly). */
280 pool_header_t *p = pool_header (v);
283 clib_bitmap_free (p->free_bitmap);
284 vec_free (p->free_indices);
285 vec_free_h (v, pool_aligned_header_bytes);
290 #define pool_free(p) (p) = _pool_free(p)
292 /** Optimized iteration through pool.
294 @param LO pointer to first element in chunk
295 @param HI pointer to last element in chunk
296 @param POOL pool to iterate across
297 @param BODY operation to perform
299 Optimized version which assumes that BODY is smart enough to
300 process multiple (LOW,HI) chunks. See also pool_foreach().
302 #define pool_foreach_region(LO,HI,POOL,BODY) \
304 uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
305 uword _pool_var (bl), * _pool_var (b); \
306 pool_header_t * _pool_var (p); \
308 _pool_var (p) = pool_header (POOL); \
309 _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
310 _pool_var (bl) = vec_len (_pool_var (b)); \
311 _pool_var (len) = vec_len (POOL); \
312 _pool_var (lo) = 0; \
314 for (_pool_var (i) = 0; \
315 _pool_var (i) <= _pool_var (bl); \
318 uword _pool_var (m), _pool_var (f); \
319 _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
320 ? _pool_var (b) [_pool_var (i)] \
322 while (_pool_var (m) != 0) \
324 _pool_var (f) = first_set (_pool_var (m)); \
325 _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
326 + min_log2 (_pool_var (f))); \
327 _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
328 ? _pool_var (hi) : _pool_var (len)); \
329 _pool_var (m) ^= _pool_var (f); \
330 if (_pool_var (hi) > _pool_var (lo)) \
332 (LO) = _pool_var (lo); \
333 (HI) = _pool_var (hi); \
334 do { BODY; } while (0); \
336 _pool_var (lo) = _pool_var (hi) + 1; \
341 /** Iterate through pool.
343 @param VAR A variable of same type as pool vector to be used as an
345 @param POOL The pool to iterate across.
346 @param BODY The operation to perform, typically a code block. See
349 This macro will call @c BODY with each active pool element.
351 It is a bad idea to allocate or free pool element from within
352 @c pool_foreach. Build a vector of indices and dispose of them later.
358 proc_t *procs; // a pool of processes.
359 proc_t *proc; // pointer to one process; used as the iterator.
361 pool_foreach (proc, procs, ({
362 if (proc->state != PROC_STATE_RUNNING)
365 // check a running proc in some way
370 @warning Because @c pool_foreach is a macro, syntax errors can be
371 difficult to find inside @c BODY, let alone actual code bugs. One
372 can temporarily split a complex @c pool_foreach into a trivial
373 @c pool_foreach which builds a vector of active indices, and a
374 vec_foreach() (or plain for-loop) to walk the active index vector.
376 #define pool_foreach(VAR,POOL,BODY) \
378 uword _pool_foreach_lo, _pool_foreach_hi; \
379 pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
381 for ((VAR) = (POOL) + _pool_foreach_lo; \
382 (VAR) < (POOL) + _pool_foreach_hi; \
384 do { BODY; } while (0); \
388 /** Returns pointer to element at given index.
390 ASSERTs that the supplied index is valid.
391 Even though one can write correct code of the form
393 p = pool_base + index;
395 use of @c pool_elt_at_index is strongly suggested.
397 #define pool_elt_at_index(p,i) \
399 typeof (p) _e = (p) + (i); \
400 ASSERT (! pool_is_free (p, _e)); \
404 /** Return next occupied pool index after @c i, useful for safe iteration. */
405 #define pool_next_index(P,I) \
407 pool_header_t * _pool_var (p) = pool_header (P); \
408 uword _pool_var (rv) = (I) + 1; \
411 (_pool_var (rv) < vec_len (P) ? \
412 clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
417 /** Iterate pool by index. */
418 #define pool_foreach_index(i,v,body) \
419 for ((i) = 0; (i) < vec_len (v); (i)++) \
421 if (! pool_is_free_index ((v), (i))) \
422 do { body; } while (0); \
426 * @brief Remove all elemenets from a pool in a safe way
428 * @param VAR each element in the pool
429 * @param POOL The pool to flush
430 * @param BODY The actions to perform on each element before it is returned to
431 * the pool. i.e. before it is 'freed'
433 #define pool_flush(VAR, POOL, BODY) \
435 uword *_pool_var(ii), *_pool_var(dv) = NULL; \
437 pool_foreach((VAR), (POOL), \
439 vec_add1(_pool_var(dv), (VAR) - (POOL)); \
441 vec_foreach(_pool_var(ii), _pool_var(dv)) \
443 (VAR) = pool_elt_at_index((POOL), *_pool_var(ii)); \
444 do { BODY; } while (0); \
445 pool_put((POOL), (VAR)); \
447 vec_free(_pool_var(dv)); \
450 #endif /* included_pool_h */
453 * fd.io coding-style-patch-verification: ON
456 * eval: (c-set-style "gnu")