src/vppinfra/pool.h

   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
   8  *
   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.
  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
  50
  51 typedef struct
  52 {
  53   /** Bitmap of indices of free objects. */
  54   uword *free_bitmap;
  55
  56   /** Vector of free indices.  One element for each set bit in bitmap. */
  57   u32 *free_indices;
  58
  59   /* The following fields are set for fixed-size, preallocated pools */
  60
  61   /** Maximum size of the pool, in elements */
  62   u32 max_elts;
  63
  64   /** mmap segment info: base + length */
  65   u8 *mmap_base;
  66   u64 mmap_size;
  67
  68 } pool_header_t;
  69
  70 /** Align pool header so that pointers are naturally aligned. */
  71 #define pool_aligned_header_bytes                                             \
  72   round_pow2 (sizeof (pool_header_t), sizeof (void *))
  73
  74 /** Get pool header from user pool pointer */
  75 always_inline pool_header_t *
  76 pool_header (void *v)
  77 {
  78   return vec_aligned_header (v, sizeof (pool_header_t), sizeof (void *));
  79 }
  80
  81 extern void _pool_init_fixed (void **, u32, u32);
  82 extern void fpool_free (void *);
  83
  84 /** initialize a fixed-size, preallocated pool */
  85 #define pool_init_fixed(pool,max_elts)                  \
  86 {                                                       \
  87   _pool_init_fixed((void **)&(pool),sizeof(pool[0]),max_elts);  \
  88 }
  89
  90 /** Validate a pool */
  91 always_inline void
  92 pool_validate (void *v)
  93 {
  94   pool_header_t *p = pool_header (v);
  95   uword i, n_free_bitmap;
  96
  97   if (!v)
  98     return;
  99
 100   n_free_bitmap = clib_bitmap_count_set_bits (p->free_bitmap);
 101   ASSERT (n_free_bitmap == vec_len (p->free_indices));
 102   for (i = 0; i < vec_len (p->free_indices); i++)
 103     ASSERT (clib_bitmap_get (p->free_bitmap, p->free_indices[i]) == 1);
 104 }
 105
 106 always_inline void
 107 pool_header_validate_index (void *v, uword index)
 108 {
 109   pool_header_t *p = pool_header (v);
 110
 111   if (v)
 112     vec_validate (p->free_bitmap, index / BITS (uword));
 113 }
 114
 115 #define pool_validate_index(v,i)                                \
 116 do {                                                            \
 117   uword __pool_validate_index = (i);                            \
 118   vec_validate_ha ((v), __pool_validate_index,                  \
 119                    pool_aligned_header_bytes, /* align */ 0);   \
 120   pool_header_validate_index ((v), __pool_validate_index);      \
 121 } while (0)
 122
 123 /** Number of active elements in a pool.
 124  * @return Number of active elements in a pool
 125  */
 126 always_inline uword
 127 pool_elts (void *v)
 128 {
 129   uword ret = vec_len (v);
 130   if (v)
 131     ret -= vec_len (pool_header (v)->free_indices);
 132   return ret;
 133 }
 134
 135 /** Number of elements in pool vector.
 136
 137     @note You probably want to call pool_elts() instead.
 138 */
 139 #define pool_len(p)     vec_len(p)
 140
 141 /** Number of elements in pool vector (usable as an lvalue)
 142
 143     @note You probably don't want to use this macro.
 144 */
 145 #define _pool_len(p)    _vec_len(p)
 146
 147 /** Memory usage of pool header. */
 148 always_inline uword
 149 pool_header_bytes (void *v)
 150 {
 151   pool_header_t *p = pool_header (v);
 152
 153   if (!v)
 154     return 0;
 155
 156   return vec_bytes (p->free_bitmap) + vec_bytes (p->free_indices);
 157 }
 158
 159 /** Memory usage of pool. */
 160 #define pool_bytes(P) (vec_bytes (P) + pool_header_bytes (P))
 161
 162 /** Local variable naming macro. */
 163 #define _pool_var(v) _pool_##v
 164
 165 /** Number of bytes that can fit into pool with current allocation */
 166 #define pool_capacity(P) vec_capacity (P, pool_aligned_header_bytes)
 167
 168 /** Number of elements that can fit into pool with current allocation */
 169 #define pool_max_len(P) (pool_capacity (P) / sizeof (P[0]))
 170
 171 /** Number of free elements in pool */
 172 #define pool_free_elts(P)                                                     \
 173   ({                                                                          \
 174     pool_header_t *_pool_var (p) = pool_header (P);                           \
 175     uword n_free = 0;                                                         \
 176     if (P)                                                                    \
 177       {                                                                       \
 178         n_free += vec_len (_pool_var (p)->free_indices);                      \
 179         /* Fixed-size pools have max_elts set non-zero */                     \
 180         if (_pool_var (p)->max_elts == 0)                                     \
 181           n_free += pool_max_len (P) - vec_len (P);                           \
 182       }                                                                       \
 183     n_free;                                                                   \
 184   })
 185
 186 /** Allocate an object E from a pool P (general version).
 187
 188    First search free list.  If nothing is free extend vector of objects.
 189 */
 190 #define _pool_get_aligned_internal_numa(P,E,A,Z,N)                      \
 191 do {                                                                    \
 192   pool_header_t * _pool_var (p) = pool_header (P);                      \
 193   uword _pool_var (l);                                                  \
 194                                                                         \
 195   STATIC_ASSERT(A==0 || ((A % sizeof(P[0]))==0)                         \
 196                 || ((sizeof(P[0]) % A) == 0),                           \
 197                 "Pool aligned alloc of incorrectly sized object");      \
 198   _pool_var (l) = 0;                                                    \
 199   if (P)                                                                \
 200     _pool_var (l) = vec_len (_pool_var (p)->free_indices);              \
 201                                                                         \
 202   if (_pool_var (l) > 0)                                                \
 203     {                                                                   \
 204       /* Return free element from free list. */                         \
 205       uword _pool_var (i) =                                             \
 206         _pool_var (p)->free_indices[_pool_var (l) - 1];                 \
 207       (E) = (P) + _pool_var (i);                                        \
 208       _pool_var (p)->free_bitmap =                                      \
 209         clib_bitmap_andnoti_notrim (_pool_var (p)->free_bitmap,         \
 210                                      _pool_var (i));                    \
 211       _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1;       \
 212       CLIB_MEM_UNPOISON((E), sizeof((E)[0]));                           \
 213     }                                                                   \
 214   else                                                                  \
 215     {                                                                   \
 216       /* fixed-size, preallocated pools cannot expand */                \
 217       if ((P) && _pool_var(p)->max_elts)                                \
 218         {                                                               \
 219           clib_warning ("can't expand fixed-size pool");                \
 220           os_out_of_memory();                                           \
 221         }                                                               \
 222       /* Nothing on free list, make a new element and return it. */     \
 223       P = _vec_resize_numa (P,                                          \
 224                        /* length_increment */ 1,                        \
 225                        /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
 226                        pool_aligned_header_bytes,                       \
 227                        /* align */ (A),                                 \
 228                        /* numa */ (N));                                 \
 229       E = vec_end (P) - 1;                                              \
 230     }                                                                   \
 231   if (Z)                                                                \
 232     memset(E, 0, sizeof(*E));                                           \
 233 } while (0)
 234
 235 #define pool_get_aligned_zero_numa(P,E,A,Z,S) \
 236   _pool_get_aligned_internal_numa(P,E,A,Z,S)
 237
 238 #define pool_get_aligned_numa(P,E,A,S) \
 239   _pool_get_aligned_internal_numa(P,E,A,0/*zero*/,S)
 240
 241 #define pool_get_numa(P,E,S) \
 242   _pool_get_aligned_internal_numa(P,E,0/*align*/,0/*zero*/,S)
 243
 244 #define _pool_get_aligned_internal(P,E,A,Z) \
 245   _pool_get_aligned_internal_numa(P,E,A,Z,VEC_NUMA_UNSPECIFIED)
 246
 247 /** Allocate an object E from a pool P with alignment A */
 248 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
 249
 250 /** Allocate an object E from a pool P with alignment A and zero it */
 251 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
 252
 253 /** Allocate an object E from a pool P (unspecified alignment). */
 254 #define pool_get(P,E) pool_get_aligned(P,E,0)
 255
 256 /** Allocate an object E from a pool P and zero it */
 257 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
 258
 259 /** See if pool_get will expand the pool or not */
 260 #define pool_get_aligned_will_expand(P,YESNO,A)                         \
 261 do {                                                                    \
 262   pool_header_t * _pool_var (p) = pool_header (P);                      \
 263   uword _pool_var (l);                                                  \
 264                                                                         \
 265   _pool_var (l) = 0;                                                    \
 266   if (P)                                                                \
 267     {                                                                   \
 268       if (_pool_var (p)->max_elts)                                      \
 269         _pool_var (l) = _pool_var (p)->max_elts;                        \
 270       else                                                              \
 271         _pool_var (l) = vec_len (_pool_var (p)->free_indices);          \
 272     }                                                                   \
 273                                                                         \
 274   /* Free elements, certainly won't expand */                           \
 275   if (_pool_var (l) > 0)                                                \
 276       YESNO=0;                                                          \
 277   else                                                                  \
 278     {                                                                   \
 279       /* Nothing on free list, make a new element and return it. */     \
 280       YESNO = _vec_resize_will_expand                                   \
 281         (P,                                                             \
 282          /* length_increment */ 1,                                      \
 283          /* new size */ (vec_len (P) + 1) * sizeof (P[0]),              \
 284          pool_aligned_header_bytes,                                     \
 285          /* align */ (A));                                              \
 286     }                                                                   \
 287 } while (0)
 288
 289 /** See if pool_put will expand free_bitmap or free_indices or not */
 290 #define pool_put_will_expand(P, E, YESNO)                                     \
 291   do                                                                          \
 292     {                                                                         \
 293       pool_header_t *_pool_var (p) = pool_header (P);                         \
 294                                                                               \
 295       uword _pool_var (i) = (E) - (P);                                        \
 296       /* free_bitmap or free_indices may expand. */                           \
 297       YESNO =                                                                 \
 298         clib_bitmap_will_expand (_pool_var (p)->free_bitmap, _pool_var (i));  \
 299                                                                               \
 300       YESNO += _vec_resize_will_expand (                                      \
 301         _pool_var (p)->free_indices, 1,                                       \
 302         (vec_len (_pool_var (p)->free_indices) + 1) *                         \
 303           sizeof (_pool_var (p)->free_indices[0]),                            \
 304         0, 0);                                                                \
 305     }                                                                         \
 306   while (0)
 307
 308 /** Tell the caller if pool get will expand the pool */
 309 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
 310
 311 /** Use free bitmap to query whether given element is free. */
 312 #define pool_is_free(P,E)                                               \
 313 ({                                                                      \
 314   pool_header_t * _pool_var (p) = pool_header (P);                      \
 315   uword _pool_var (i) = (E) - (P);                                      \
 316   (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
 317 })
 318
 319 /** Use free bitmap to query whether given index is free */
 320 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
 321
 322 /** Free an object E in pool P. */
 323 #define pool_put(P, E)                                                        \
 324   do                                                                          \
 325     {                                                                         \
 326       typeof (P) _pool_var (p__) = (P);                                       \
 327       typeof (E) _pool_var (e__) = (E);                                       \
 328       pool_header_t *_pool_var (p) = pool_header (_pool_var (p__));           \
 329       uword _pool_var (l) = _pool_var (e__) - _pool_var (p__);                \
 330       if (_pool_var (p)->max_elts == 0)                                       \
 331         ASSERT (vec_is_member (_pool_var (p__), _pool_var (e__)));            \
 332       ASSERT (!pool_is_free (_pool_var (p__), _pool_var (e__)));              \
 333                                                                               \
 334       /* Add element to free bitmap and to free list. */                      \
 335       _pool_var (p)->free_bitmap =                                            \
 336         clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap, _pool_var (l));   \
 337                                                                               \
 338       /* Preallocated pool? */                                                \
 339       if (_pool_var (p)->max_elts)                                            \
 340         {                                                                     \
 341           ASSERT (_pool_var (l) < _pool_var (p)->max_elts);                   \
 342           _pool_var (p)                                                       \
 343             ->free_indices[_vec_len (_pool_var (p)->free_indices)] =          \
 344             _pool_var (l);                                                    \
 345           _vec_len (_pool_var (p)->free_indices) += 1;                        \
 346         }                                                                     \
 347       else                                                                    \
 348         vec_add1 (_pool_var (p)->free_indices, _pool_var (l));                \
 349                                                                               \
 350       CLIB_MEM_POISON (_pool_var (e__), sizeof (_pool_var (e__)[0]));         \
 351     }                                                                         \
 352   while (0)
 353
 354 /** Free pool element with given index. */
 355 #define pool_put_index(p,i)                     \
 356 do {                                            \
 357   typeof (p) _e = (p) + (i);                    \
 358   pool_put (p, _e);                             \
 359 } while (0)
 360
 361 /** Allocate N more free elements to pool (general version). */
 362 #define pool_alloc_aligned(P,N,A)                                       \
 363 do {                                                                    \
 364   pool_header_t * _p;                                                   \
 365                                                                         \
 366   if ((P))                                                              \
 367     {                                                                   \
 368       _p = pool_header (P);                                             \
 369       if (_p->max_elts)                                                 \
 370         {                                                               \
 371            clib_warning ("Can't expand fixed-size pool");               \
 372            os_out_of_memory();                                          \
 373         }                                                               \
 374     }                                                                   \
 375                                                                         \
 376   (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]),       \
 377                      pool_aligned_header_bytes,                         \
 378                      (A));                                              \
 379   _p = pool_header (P);                                                 \
 380   vec_resize (_p->free_indices, (N));                                   \
 381   _vec_len (_p->free_indices) -= (N);                                   \
 382 } while (0)
 383
 384 /** Allocate N more free elements to pool (unspecified alignment). */
 385 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
 386
 387 /**
 388  * Return copy of pool with alignment
 389  *
 390  * @param P pool to copy
 391  * @param A alignment (may be zero)
 392  * @return copy of pool
 393  */
 394 #define pool_dup_aligned(P, A)                                                \
 395   ({                                                                          \
 396     typeof (P) _pool_var (new) = 0;                                           \
 397     pool_header_t *_pool_var (ph), *_pool_var (new_ph);                       \
 398     u32 _pool_var (n) = pool_len (P);                                         \
 399     if ((P))                                                                  \
 400       {                                                                       \
 401         _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n),        \
 402                                        _pool_var (n) * sizeof ((P)[0]),       \
 403                                        pool_aligned_header_bytes, (A));       \
 404         CLIB_MEM_OVERFLOW_PUSH ((P), _pool_var (n) * sizeof ((P)[0]));        \
 405         clib_memcpy_fast (_pool_var (new), (P),                               \
 406                           _pool_var (n) * sizeof ((P)[0]));                   \
 407         CLIB_MEM_OVERFLOW_POP ();                                             \
 408         _pool_var (ph) = pool_header (P);                                     \
 409         _pool_var (new_ph) = pool_header (_pool_var (new));                   \
 410         _pool_var (new_ph)->free_bitmap =                                     \
 411           clib_bitmap_dup (_pool_var (ph)->free_bitmap);                      \
 412         _pool_var (new_ph)->free_indices =                                    \
 413           vec_dup (_pool_var (ph)->free_indices);                             \
 414         _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts;              \
 415       }                                                                       \
 416     _pool_var (new);                                                          \
 417   })
 418
 419 /**
 420  * Return copy of pool without alignment
 421  *
 422  * @param P pool to copy
 423  * @return copy of pool
 424  */
 425 #define pool_dup(P) pool_dup_aligned(P,0)
 426
 427 /** Low-level free pool operator (do not call directly). */
 428 always_inline void *
 429 _pool_free (void *v)
 430 {
 431   pool_header_t *p = pool_header (v);
 432   if (!v)
 433     return v;
 434   clib_bitmap_free (p->free_bitmap);
 435
 436   if (p->max_elts)
 437     {
 438       int rv;
 439
 440       rv = munmap (p->mmap_base, p->mmap_size);
 441       if (rv)
 442         clib_unix_warning ("munmap");
 443     }
 444   else
 445     {
 446       vec_free (p->free_indices);
 447       vec_free_h (v, pool_aligned_header_bytes);
 448     }
 449   return 0;
 450 }
 451
 452 static_always_inline uword
 453 pool_get_first_index (void *pool)
 454 {
 455   pool_header_t *h = pool_header (pool);
 456   return clib_bitmap_first_clear (h->free_bitmap);
 457 }
 458
 459 static_always_inline uword
 460 pool_get_next_index (void *pool, uword last)
 461 {
 462   pool_header_t *h = pool_header (pool);
 463   return clib_bitmap_next_clear (h->free_bitmap, last + 1);
 464 }
 465
 466 /** Free a pool. */
 467 #define pool_free(p) (p) = _pool_free(p)
 468
 469 /** Optimized iteration through pool.
 470
 471     @param LO pointer to first element in chunk
 472     @param HI pointer to last element in chunk
 473     @param POOL pool to iterate across
 474     @param BODY operation to perform
 475
 476     Optimized version which assumes that BODY is smart enough to
 477     process multiple (LOW,HI) chunks. See also pool_foreach().
 478  */
 479 #define pool_foreach_region(LO,HI,POOL,BODY)                            \
 480 do {                                                                    \
 481   uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
 482   uword _pool_var (bl), * _pool_var (b);                                \
 483   pool_header_t * _pool_var (p);                                        \
 484                                                                         \
 485   _pool_var (p) = pool_header (POOL);                                   \
 486   _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0;              \
 487   _pool_var (bl) = vec_len (_pool_var (b));                             \
 488   _pool_var (len) = vec_len (POOL);                                     \
 489   _pool_var (lo) = 0;                                                   \
 490                                                                         \
 491   for (_pool_var (i) = 0;                                               \
 492        _pool_var (i) <= _pool_var (bl);                                 \
 493        _pool_var (i)++)                                                 \
 494     {                                                                   \
 495       uword _pool_var (m), _pool_var (f);                               \
 496       _pool_var (m) = (_pool_var (i) < _pool_var (bl)                   \
 497                        ? _pool_var (b) [_pool_var (i)]                  \
 498                        : 1);                                            \
 499       while (_pool_var (m) != 0)                                        \
 500         {                                                               \
 501           _pool_var (f) = first_set (_pool_var (m));                    \
 502           _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0])     \
 503                             + min_log2 (_pool_var (f)));                \
 504           _pool_var (hi) = (_pool_var (i) < _pool_var (bl)              \
 505                             ? _pool_var (hi) : _pool_var (len));        \
 506           _pool_var (m) ^= _pool_var (f);                               \
 507           if (_pool_var (hi) > _pool_var (lo))                          \
 508             {                                                           \
 509               (LO) = _pool_var (lo);                                    \
 510               (HI) = _pool_var (hi);                                    \
 511               do { BODY; } while (0);                                   \
 512             }                                                           \
 513           _pool_var (lo) = _pool_var (hi) + 1;                          \
 514         }                                                               \
 515     }                                                                   \
 516 } while (0)
 517
 518 /** Iterate through pool.
 519
 520     @param VAR A variable of same type as pool vector to be used as an
 521                iterator.
 522     @param POOL The pool to iterate across.
 523     @param BODY The operation to perform, typically a code block. See
 524                 the example below.
 525
 526     This macro will call @c BODY with each active pool element.
 527
 528     It is a bad idea to allocate or free pool element from within
 529     @c pool_foreach. Build a vector of indices and dispose of them later.
 530     Or call pool_flush.
 531
 532
 533     @par Example
 534     @code{.c}
 535     proc_t *procs;   // a pool of processes.
 536     proc_t *proc;    // pointer to one process; used as the iterator.
 537
 538     pool_foreach (proc, procs, ({
 539         if (proc->state != PROC_STATE_RUNNING)
 540             continue;
 541
 542         // check a running proc in some way
 543         ...
 544     }));
 545     @endcode
 546
 547     @warning Because @c pool_foreach is a macro, syntax errors can be
 548     difficult to find inside @c BODY, let alone actual code bugs. One
 549     can temporarily split a complex @c pool_foreach into a trivial
 550     @c pool_foreach which builds a vector of active indices, and a
 551     vec_foreach() (or plain for-loop) to walk the active index vector.
 552  */
 553
 554 #define pool_foreach(VAR,POOL)                                          \
 555   if (POOL)                                                             \
 556     for (VAR = POOL + pool_get_first_index (POOL);                      \
 557          VAR < vec_end (POOL);                                          \
 558          VAR = POOL + pool_get_next_index (POOL, VAR - POOL))
 559
 560 /** Returns pointer to element at given index.
 561
 562     ASSERTs that the supplied index is valid.
 563     Even though one can write correct code of the form
 564     @code
 565         p = pool_base + index;
 566     @endcode
 567     use of @c pool_elt_at_index is strongly suggested.
 568  */
 569 #define pool_elt_at_index(p,i)                  \
 570 ({                                              \
 571   typeof (p) _e = (p) + (i);                    \
 572   ASSERT (! pool_is_free (p, _e));              \
 573   _e;                                           \
 574 })
 575
 576 /** Return next occupied pool index after @c i, useful for safe iteration. */
 577 #define pool_next_index(P,I)                                            \
 578 ({                                                                      \
 579   pool_header_t * _pool_var (p) = pool_header (P);                      \
 580   uword _pool_var (rv) = (I) + 1;                                       \
 581                                                                         \
 582   _pool_var(rv) =                                                       \
 583     (_pool_var (rv) < vec_len (P) ?                                     \
 584      clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
 585      : ~0);                                                             \
 586   _pool_var(rv) =                                                       \
 587     (_pool_var (rv) < vec_len (P) ?                                     \
 588      _pool_var (rv) : ~0);                                              \
 589   _pool_var(rv);                                                        \
 590 })
 591
 592 #define pool_foreach_index(i,v)         \
 593   if (v)                                        \
 594     for (i = pool_get_first_index (v);          \
 595          i < vec_len (v);                       \
 596          i = pool_get_next_index (v, i))        \
 597
 598 /**
 599  * @brief Remove all elements from a pool in a safe way
 600  *
 601  * @param VAR each element in the pool
 602  * @param POOL The pool to flush
 603  * @param BODY The actions to perform on each element before it is returned to
 604  *        the pool. i.e. before it is 'freed'
 605  */
 606 #define pool_flush(VAR, POOL, BODY)                     \
 607 {                                                       \
 608   uword *_pool_var(ii), *_pool_var(dv) = NULL;          \
 609                                                         \
 610   pool_foreach((VAR), (POOL))                          \
 611   {                                                     \
 612     vec_add1(_pool_var(dv), (VAR) - (POOL));            \
 613   }                                                     \
 614   vec_foreach(_pool_var(ii), _pool_var(dv))             \
 615   {                                                     \
 616     (VAR) = pool_elt_at_index((POOL), *_pool_var(ii));  \
 617     do { BODY; } while (0);                             \
 618     pool_put((POOL), (VAR));                            \
 619   }                                                     \
 620   vec_free(_pool_var(dv));                              \
 621 }
 622
 623 #endif /* included_pool_h */
 624
 625 /*
 626  * fd.io coding-style-patch-verification: ON
 627  *
 628  * Local Variables:
 629  * eval: (c-set-style "gnu")
 630  * End:
 631  */