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 /** Use free bitmap to query whether given element is free. */
203 #define pool_is_free(P,E) \
205 pool_header_t * _pool_var (p) = pool_header (P); \
206 uword _pool_var (i) = (E) - (P); \
207 (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
210 /** Use free bitmap to query whether given index is free */
211 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
213 /** Free an object E in pool P. */
214 #define pool_put(P,E) \
216 pool_header_t * _pool_var (p) = pool_header (P); \
217 uword _pool_var (l) = (E) - (P); \
218 ASSERT (vec_is_member (P, E)); \
219 ASSERT (! pool_is_free (P, E)); \
221 /* Add element to free bitmap and to free list. */ \
222 _pool_var (p)->free_bitmap = \
223 clib_bitmap_ori (_pool_var (p)->free_bitmap, _pool_var (l)); \
224 vec_add1 (_pool_var (p)->free_indices, _pool_var (l)); \
227 /** Free pool element with given index. */
228 #define pool_put_index(p,i) \
230 typeof (p) _e = (p) + (i); \
234 /** Allocate N more free elements to pool (general version). */
235 #define pool_alloc_aligned(P,N,A) \
237 pool_header_t * _p; \
238 (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]), \
239 pool_aligned_header_bytes, \
241 _p = pool_header (P); \
242 vec_resize (_p->free_indices, (N)); \
243 _vec_len (_p->free_indices) -= (N); \
246 /** Allocate N more free elements to pool (unspecified alignment). */
247 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
249 /** Low-level free pool operator (do not call directly). */
253 pool_header_t *p = pool_header (v);
256 clib_bitmap_free (p->free_bitmap);
257 vec_free (p->free_indices);
258 vec_free_h (v, pool_aligned_header_bytes);
263 #define pool_free(p) (p) = _pool_free(p)
265 /** Optimized iteration through pool.
267 @param LO pointer to first element in chunk
268 @param HI pointer to last element in chunk
269 @param POOL pool to iterate across
270 @param BODY operation to perform
272 Optimized version which assumes that BODY is smart enough to
273 process multiple (LOW,HI) chunks. See also pool_foreach().
275 #define pool_foreach_region(LO,HI,POOL,BODY) \
277 uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
278 uword _pool_var (bl), * _pool_var (b); \
279 pool_header_t * _pool_var (p); \
281 _pool_var (p) = pool_header (POOL); \
282 _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0; \
283 _pool_var (bl) = vec_len (_pool_var (b)); \
284 _pool_var (len) = vec_len (POOL); \
285 _pool_var (lo) = 0; \
287 for (_pool_var (i) = 0; \
288 _pool_var (i) <= _pool_var (bl); \
291 uword _pool_var (m), _pool_var (f); \
292 _pool_var (m) = (_pool_var (i) < _pool_var (bl) \
293 ? _pool_var (b) [_pool_var (i)] \
295 while (_pool_var (m) != 0) \
297 _pool_var (f) = first_set (_pool_var (m)); \
298 _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0]) \
299 + min_log2 (_pool_var (f))); \
300 _pool_var (hi) = (_pool_var (i) < _pool_var (bl) \
301 ? _pool_var (hi) : _pool_var (len)); \
302 _pool_var (m) ^= _pool_var (f); \
303 if (_pool_var (hi) > _pool_var (lo)) \
305 (LO) = _pool_var (lo); \
306 (HI) = _pool_var (hi); \
307 do { BODY; } while (0); \
309 _pool_var (lo) = _pool_var (hi) + 1; \
314 /** Iterate through pool.
316 @param VAR A variable of same type as pool vector to be used as an
318 @param POOL The pool to iterate across.
319 @param BODY The operation to perform, typically a code block. See
322 This macro will call @c BODY with each active pool element.
324 It is a bad idea to allocate or free pool element from within
325 @c pool_foreach. Build a vector of indices and dispose of them later.
330 proc_t *procs; // a pool of processes.
331 proc_t *proc; // pointer to one process; used as the iterator.
333 pool_foreach (proc, procs, ({
334 if (proc->state != PROC_STATE_RUNNING)
337 // check a running proc in some way
342 @warning Because @c pool_foreach is a macro, syntax errors can be
343 difficult to find inside @c BODY, let alone actual code bugs. One
344 can temporarily split a complex @c pool_foreach into a trivial
345 @c pool_foreach which builds a vector of active indices, and a
346 vec_foreach() (or plain for-loop) to walk the active index vector.
348 #define pool_foreach(VAR,POOL,BODY) \
350 uword _pool_foreach_lo, _pool_foreach_hi; \
351 pool_foreach_region (_pool_foreach_lo, _pool_foreach_hi, (POOL), \
353 for ((VAR) = (POOL) + _pool_foreach_lo; \
354 (VAR) < (POOL) + _pool_foreach_hi; \
356 do { BODY; } while (0); \
360 /** Returns pointer to element at given index.
362 ASSERTs that the supplied index is valid.
363 Even though one can write correct code of the form
365 p = pool_base + index;
367 use of @c pool_elt_at_index is strongly suggested.
369 #define pool_elt_at_index(p,i) \
371 typeof (p) _e = (p) + (i); \
372 ASSERT (! pool_is_free (p, _e)); \
376 /** Return next occupied pool index after @c i, useful for safe iteration. */
377 #define pool_next_index(P,I) \
379 pool_header_t * _pool_var (p) = pool_header (P); \
380 uword _pool_var (rv) = (I) + 1; \
383 (_pool_var (rv) < vec_len (P) ? \
384 clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
389 /** Iterate pool by index. */
390 #define pool_foreach_index(i,v,body) \
391 for ((i) = 0; (i) < vec_len (v); (i)++) \
393 if (! pool_is_free_index ((v), (i))) \
394 do { body; } while (0); \
397 #endif /* included_pool_h */
400 * fd.io coding-style-patch-verification: ON
403 * eval: (c-set-style "gnu")