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>
53 /** Bitmap of indices of free objects. */
56 /** Vector of free indices. One element for each set bit in bitmap. */
60 /** Align pool header so that pointers are naturally aligned. */
61 #define pool_aligned_header_bytes \
62 vec_aligned_header_bytes (sizeof (pool_header_t), sizeof (void *))
64 /** Get pool header from user pool pointer */
65 always_inline pool_header_t * pool_header (void * v)
66 { return vec_aligned_header (v, sizeof (pool_header_t), sizeof (void *)); }
68 /** Validate a pool */
69 always_inline void pool_validate (void * v)
71 pool_header_t * p = pool_header (v);
72 uword i, n_free_bitmap;
77 n_free_bitmap = clib_bitmap_count_set_bits (p->free_bitmap);
78 ASSERT (n_free_bitmap == vec_len (p->free_indices));
79 for (i = 0; i < vec_len (p->free_indices); i++)
80 ASSERT (clib_bitmap_get (p->free_bitmap, p->free_indices[i]) == 1);
83 always_inline void pool_header_validate_index (void * v, uword index)
85 pool_header_t * p = pool_header (v);
88 vec_validate (p->free_bitmap, index / BITS (uword));
91 #define pool_validate_index(v,i) \
93 uword __pool_validate_index = (i); \
94 vec_validate_ha ((v), __pool_validate_index, \
95 pool_aligned_header_bytes, /* align */ 0); \
96 pool_header_validate_index ((v), __pool_validate_index); \
99 /** Number of active elements in a pool.
100 * @return Number of active elements in a pool
102 always_inline uword pool_elts (void * v)
104 uword ret = vec_len (v);
106 ret -= vec_len (pool_header (v)->free_indices);
110 /** Number of elements in pool vector.
112 @note You probably want to call pool_elts() instead.
114 #define pool_len(p) vec_len(p)
116 /** Number of elements in pool vector (usable as an lvalue)
118 @note You probably don't want to use this macro.
120 #define _pool_len(p) _vec_len(p)
122 /** Memory usage of pool header. */
124 pool_header_bytes (void * v)
126 pool_header_t * p = pool_header (v);
131 return vec_bytes (p->free_bitmap) + vec_bytes (p->free_indices);
134 /** Memory usage of pool. */
135 #define pool_bytes(P) (vec_bytes (P) + pool_header_bytes (P))
137 /** Local variable naming macro. */
138 #define _pool_var(v) _pool_##v
140 /** Queries whether pool has at least N_FREE free elements. */
142 pool_free_elts (void * v)
144 pool_header_t * p = pool_header (v);
148 n_free += vec_len (p->free_indices);
150 /* Space left at end of vector? */
151 n_free += vec_capacity (v, sizeof (p[0])) - vec_len (v);
157 /** Allocate an object E from a pool P (general version).
159 First search free list. If nothing is free extend vector of objects.
161 #define pool_get_aligned(P,E,A) \
163 pool_header_t * _pool_var (p) = pool_header (P); \
164 uword _pool_var (l); \
168 _pool_var (l) = vec_len (_pool_var (p)->free_indices); \
170 if (_pool_var (l) > 0) \
172 /* Return free element from free list. */ \
173 uword _pool_var (i) = _pool_var (p)->free_indices[_pool_var (l) - 1]; \
174 (E) = (P) + _pool_var (i); \
175 _pool_var (p)->free_bitmap = \
176 clib_bitmap_andnoti (_pool_var (p)->free_bitmap, _pool_var (i)); \
177 _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1; \
181 /* Nothing on free list, make a new element and return it. */ \
182 P = _vec_resize (P, \
183 /* length_increment */ 1, \
184 /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
185 pool_aligned_header_bytes, \
187 E = vec_end (P) - 1; \
191 /** Allocate an object E from a pool P (unspecified alignment). */
192 #define pool_get(P,E) pool_get_aligned(P,E,0)
194 /** Use free bitmap to query whether given element is free. */
195 #define pool_is_free(P,E) \
197 pool_header_t * _pool_var (p) = pool_header (P); \
198 uword _pool_var (i) = (E) - (P); \
199 (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
202 /** Use free bitmap to query whether given index is free */
203 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
205 /** Free an object E in pool P. */
206 #define pool_put(P,E) \
208 pool_header_t * _pool_var (p) = pool_header (P); \
209 uword _pool_var (l) = (E) - (P); \
210 ASSERT (vec_is_member (P, E)); \
211 ASSERT (! pool_is_free (P, E)); \
213 /* Add element to free bitmap and to free list. */ \
214 _pool_var (p)->free_bitmap = \
215 clib_bitmap_ori (_pool_var (p)->free_bitmap, _pool_var (l)); \
216 vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
219 /** Free pool element with given index. */
220 #define pool_put_index(p,i) \
222 typeof (p) _e = (p) + (i); \
226 /** Allocate N more free elements to pool (general version). */
227 #define pool_alloc_aligned(P,N,A) \
229 pool_header_t * _p; \
230 (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
231 pool_aligned_header_bytes, \
233 _p = pool_header (P); \
234 vec_resize (_p->free_indices, (N)); \
235 _vec_len (_p->free_indices) -= (N); \
238 /** Allocate N more free elements to pool (unspecified alignment). */
239 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
241 /** Low-level free pool operator (do not call directly). */
242 always_inline void * _pool_free (void * v)
244 pool_header_t * p = pool_header (v);
247 clib_bitmap_free (p->free_bitmap);
248 vec_free (p->free_indices);
249 vec_free_h (v, pool_aligned_header_bytes);
254 #define pool_free(p) (p) = _pool_free(p)
256 /** Optimized iteration through pool.
258 @param LO pointer to first element in chunk
259 @param HI pointer to last element in chunk
260 @param POOL pool to iterate across
261 @param BODY operation to perform
263 Optimized version which assumes that BODY is smart enough to
264 process multiple (LOW,HI) chunks. See also pool_foreach().
266 #define pool_foreach_region(LO,HI,POOL,BODY) \
268 uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
269 uword _pool_var (bl), * _pool_var (b); \
270 pool_header_t * _pool_var (p); \
272 _pool_var (p) = pool_header (POOL); \
273 _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
274 _pool_var (bl) = vec_len (_pool_var (b)); \
275 _pool_var (len) = vec_len (POOL); \
276 _pool_var (lo) = 0; \
278 for (_pool_var (i) = 0; \
279 _pool_var (i) <= _pool_var (bl); \
282 uword _pool_var (m), _pool_var (f); \
283 _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
284 ? _pool_var (b) [_pool_var (i)] \
286 while (_pool_var (m) != 0) \
288 _pool_var (f) = first_set (_pool_var (m)); \
289 _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
290 + min_log2 (_pool_var (f))); \
291 _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
292 ? _pool_var (hi) : _pool_var (len)); \
293 _pool_var (m) ^= _pool_var (f); \
294 if (_pool_var (hi) > _pool_var (lo)) \
296 (LO) = _pool_var (lo); \
297 (HI) = _pool_var (hi); \
298 do { BODY; } while (0); \
300 _pool_var (lo) = _pool_var (hi) + 1; \
305 /** Iterate through pool.
307 @param VAR A variable of same type as pool vector to be used as an
309 @param POOL The pool to iterate across.
310 @param BODY The operation to perform, typically a code block. See
313 This macro will call @c BODY with each active pool element.
315 It is a bad idea to allocate or free pool element from within
316 @c pool_foreach. Build a vector of indices and dispose of them later.
321 proc_t *procs; // a pool of processes.
322 proc_t *proc; // pointer to one process; used as the iterator.
324 pool_foreach (proc, procs, ({
325 if (proc->state != PROC_STATE_RUNNING)
328 // check a running proc in some way
333 @warning Because @c pool_foreach is a macro, syntax errors can be
334 difficult to find inside @c BODY, let alone actual code bugs. One
335 can temporarily split a complex @c pool_foreach into a trivial
336 @c pool_foreach which builds a vector of active indices, and a
337 vec_foreach() (or plain for-loop) to walk the active index vector.
339 #define pool_foreach(VAR,POOL,BODY) \
341 uword _pool_foreach_lo, _pool_foreach_hi; \
342 pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
344 for ((VAR) = (POOL) + _pool_foreach_lo; \
345 (VAR) < (POOL) + _pool_foreach_hi; \
347 do { BODY; } while (0); \
351 /** Returns pointer to element at given index.
353 ASSERTs that the supplied index is valid.
354 Even though one can write correct code of the form
356 p = pool_base + index;
358 use of @c pool_elt_at_index is strongly suggested.
360 #define pool_elt_at_index(p,i) \
362 typeof (p) _e = (p) + (i); \
363 ASSERT (! pool_is_free (p, _e)); \
367 /** Return next occupied pool index after @c i, useful for safe iteration. */
368 #define pool_next_index(P,I) \
370 pool_header_t * _pool_var (p) = pool_header (P); \
371 uword _pool_var (rv) = (I) + 1; \
374 (_pool_var (rv) < vec_len (P) ? \
375 clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
380 /** Iterate pool by index. */
381 #define pool_foreach_index(i,v,body) \
382 for ((i) = 0; (i) < vec_len (v); (i)++) \
384 if (! pool_is_free_index ((v), (i))) \
385 do { body; } while (0); \
388 #endif /* included_pool_h */