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   vec_aligned_header_bytes (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 /** Queries whether pool has at least N_FREE free elements. */
 166 always_inline uword
 167 pool_free_elts (void *v)
 168 {
 169   pool_header_t *p = pool_header (v);
 170   uword n_free = 0;
 171
 172   if (v)
 173     {
 174       n_free += vec_len (p->free_indices);
 175
 176       /* Space left at end of vector? */
 177       n_free += vec_capacity (v, sizeof (p[0])) - vec_len (v);
 178     }
 179
 180   return n_free;
 181 }
 182
 183 /** Allocate an object E from a pool P (general version).
 184
 185    First search free list.  If nothing is free extend vector of objects.
 186 */
 187 #define _pool_get_aligned_internal_numa(P,E,A,Z,N)                      \
 188 do {                                                                    \
 189   pool_header_t * _pool_var (p) = pool_header (P);                      \
 190   uword _pool_var (l);                                                  \
 191                                                                         \
 192   STATIC_ASSERT(A==0 || ((A % sizeof(P[0]))==0)                         \
 193                 || ((sizeof(P[0]) % A) == 0),                           \
 194                 "Pool aligned alloc of incorrectly sized object");      \
 195   _pool_var (l) = 0;                                                    \
 196   if (P)                                                                \
 197     _pool_var (l) = vec_len (_pool_var (p)->free_indices);              \
 198                                                                         \
 199   if (_pool_var (l) > 0)                                                \
 200     {                                                                   \
 201       /* Return free element from free list. */                         \
 202       uword _pool_var (i) =                                             \
 203         _pool_var (p)->free_indices[_pool_var (l) - 1];                 \
 204       (E) = (P) + _pool_var (i);                                        \
 205       _pool_var (p)->free_bitmap =                                      \
 206         clib_bitmap_andnoti_notrim (_pool_var (p)->free_bitmap,         \
 207                                      _pool_var (i));                    \
 208       _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1;       \
 209       CLIB_MEM_UNPOISON((E), sizeof((E)[0]));                           \
 210     }                                                                   \
 211   else                                                                  \
 212     {                                                                   \
 213       /* fixed-size, preallocated pools cannot expand */                \
 214       if ((P) && _pool_var(p)->max_elts)                                \
 215         {                                                               \
 216           clib_warning ("can't expand fixed-size pool");                \
 217           os_out_of_memory();                                           \
 218         }                                                               \
 219       /* Nothing on free list, make a new element and return it. */     \
 220       P = _vec_resize_numa (P,                                          \
 221                        /* length_increment */ 1,                        \
 222                        /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
 223                        pool_aligned_header_bytes,                       \
 224                        /* align */ (A),                                 \
 225                        /* numa */ (N));                                 \
 226       E = vec_end (P) - 1;                                              \
 227     }                                                                   \
 228   if (Z)                                                                \
 229     memset(E, 0, sizeof(*E));                                           \
 230 } while (0)
 231
 232 #define pool_get_aligned_zero_numa(P,E,A,Z,S) \
 233   _pool_get_aligned_internal_numa(P,E,A,Z,S)
 234
 235 #define pool_get_aligned_numa(P,E,A,S) \
 236   _pool_get_aligned_internal_numa(P,E,A,0/*zero*/,S)
 237
 238 #define pool_get_numa(P,E,S) \
 239   _pool_get_aligned_internal_numa(P,E,0/*align*/,0/*zero*/,S)
 240
 241 #define _pool_get_aligned_internal(P,E,A,Z) \
 242   _pool_get_aligned_internal_numa(P,E,A,Z,VEC_NUMA_UNSPECIFIED)
 243
 244 /** Allocate an object E from a pool P with alignment A */
 245 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
 246
 247 /** Allocate an object E from a pool P with alignment A and zero it */
 248 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
 249
 250 /** Allocate an object E from a pool P (unspecified alignment). */
 251 #define pool_get(P,E) pool_get_aligned(P,E,0)
 252
 253 /** Allocate an object E from a pool P and zero it */
 254 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
 255
 256 /** See if pool_get will expand the pool or not */
 257 #define pool_get_aligned_will_expand(P,YESNO,A)                         \
 258 do {                                                                    \
 259   pool_header_t * _pool_var (p) = pool_header (P);                      \
 260   uword _pool_var (l);                                                  \
 261                                                                         \
 262   _pool_var (l) = 0;                                                    \
 263   if (P)                                                                \
 264     {                                                                   \
 265       if (_pool_var (p)->max_elts)                                      \
 266         _pool_var (l) = _pool_var (p)->max_elts;                        \
 267       else                                                              \
 268         _pool_var (l) = vec_len (_pool_var (p)->free_indices);          \
 269     }                                                                   \
 270                                                                         \
 271   /* Free elements, certainly won't expand */                           \
 272   if (_pool_var (l) > 0)                                                \
 273       YESNO=0;                                                          \
 274   else                                                                  \
 275     {                                                                   \
 276       /* Nothing on free list, make a new element and return it. */     \
 277       YESNO = _vec_resize_will_expand                                   \
 278         (P,                                                             \
 279          /* length_increment */ 1,                                      \
 280          /* new size */ (vec_len (P) + 1) * sizeof (P[0]),              \
 281          pool_aligned_header_bytes,                                     \
 282          /* align */ (A));                                              \
 283     }                                                                   \
 284 } while (0)
 285
 286 /** Tell the caller if pool get will expand the pool */
 287 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
 288
 289 /** Use free bitmap to query whether given element is free. */
 290 #define pool_is_free(P,E)                                               \
 291 ({                                                                      \
 292   pool_header_t * _pool_var (p) = pool_header (P);                      \
 293   uword _pool_var (i) = (E) - (P);                                      \
 294   (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
 295 })
 296
 297 /** Use free bitmap to query whether given index is free */
 298 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
 299
 300 /** Free an object E in pool P. */
 301 #define pool_put(P,E)                                                   \
 302 do {                                                                    \
 303   typeof (P) _pool_var(p__) = (P);                                      \
 304   typeof (E) _pool_var(e__) = (E);                                      \
 305   pool_header_t * _pool_var (p) = pool_header (_pool_var(p__));         \
 306   uword _pool_var (l) = _pool_var(e__) - _pool_var(p__);                \
 307   ASSERT (vec_is_member (_pool_var(p__), _pool_var(e__)));              \
 308   ASSERT (! pool_is_free (_pool_var(p__), _pool_var(e__)));             \
 309                                                                         \
 310   /* Add element to free bitmap and to free list. */                    \
 311   _pool_var (p)->free_bitmap =                                          \
 312     clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap,                 \
 313                              _pool_var (l));                            \
 314                                                                         \
 315   /* Preallocated pool? */                                              \
 316   if (_pool_var (p)->max_elts)                                          \
 317     {                                                                   \
 318       ASSERT(_pool_var(l) < _pool_var (p)->max_elts);                   \
 319       _pool_var(p)->free_indices[_vec_len(_pool_var(p)->free_indices)] = \
 320                                  _pool_var(l);                          \
 321       _vec_len(_pool_var(p)->free_indices) += 1;                        \
 322     }                                                                   \
 323   else                                                                  \
 324     vec_add1 (_pool_var (p)->free_indices, _pool_var (l));              \
 325                                                                         \
 326   CLIB_MEM_POISON(_pool_var(e__), sizeof(_pool_var(e__)[0]));                                 \
 327 } while (0)
 328
 329 /** Free pool element with given index. */
 330 #define pool_put_index(p,i)                     \
 331 do {                                            \
 332   typeof (p) _e = (p) + (i);                    \
 333   pool_put (p, _e);                             \
 334 } while (0)
 335
 336 /** Allocate N more free elements to pool (general version). */
 337 #define pool_alloc_aligned(P,N,A)                                       \
 338 do {                                                                    \
 339   pool_header_t * _p;                                                   \
 340                                                                         \
 341   if ((P))                                                              \
 342     {                                                                   \
 343       _p = pool_header (P);                                             \
 344       if (_p->max_elts)                                                 \
 345         {                                                               \
 346            clib_warning ("Can't expand fixed-size pool");               \
 347            os_out_of_memory();                                          \
 348         }                                                               \
 349     }                                                                   \
 350                                                                         \
 351   (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]),       \
 352                      pool_aligned_header_bytes,                         \
 353                      (A));                                              \
 354   _p = pool_header (P);                                                 \
 355   vec_resize (_p->free_indices, (N));                                   \
 356   _vec_len (_p->free_indices) -= (N);                                   \
 357 } while (0)
 358
 359 /** Allocate N more free elements to pool (unspecified alignment). */
 360 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
 361
 362 /**
 363  * Return copy of pool with alignment
 364  *
 365  * @param P pool to copy
 366  * @param A alignment (may be zero)
 367  * @return copy of pool
 368  */
 369 #define pool_dup_aligned(P,A)                                           \
 370 ({                                                                      \
 371   typeof (P) _pool_var (new) = 0;                                       \
 372   pool_header_t * _pool_var (ph), * _pool_var (new_ph);                 \
 373   u32 _pool_var (n) = pool_len (P);                                     \
 374   if ((P))                                                              \
 375     {                                                                   \
 376       _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n),    \
 377                                      _pool_var (n) * sizeof ((P)[0]),   \
 378                                      pool_aligned_header_bytes, (A));   \
 379       clib_memcpy_fast (_pool_var (new), (P),                           \
 380                         _pool_var (n) * sizeof ((P)[0]));               \
 381       _pool_var (ph) = pool_header (P);                                 \
 382       _pool_var (new_ph) = pool_header (_pool_var (new));               \
 383       _pool_var (new_ph)->free_bitmap =                                 \
 384         clib_bitmap_dup (_pool_var (ph)->free_bitmap);                  \
 385       _pool_var (new_ph)->free_indices =                                \
 386         vec_dup (_pool_var (ph)->free_indices);                         \
 387       _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts;          \
 388     }                                                                   \
 389   _pool_var (new);                                                      \
 390 })
 391
 392 /**
 393  * Return copy of pool without alignment
 394  *
 395  * @param P pool to copy
 396  * @return copy of pool
 397  */
 398 #define pool_dup(P) pool_dup_aligned(P,0)
 399
 400 /** Low-level free pool operator (do not call directly). */
 401 always_inline void *
 402 _pool_free (void *v)
 403 {
 404   pool_header_t *p = pool_header (v);
 405   if (!v)
 406     return v;
 407   clib_bitmap_free (p->free_bitmap);
 408
 409   if (p->max_elts)
 410     {
 411       int rv;
 412
 413       rv = munmap (p->mmap_base, p->mmap_size);
 414       if (rv)
 415         clib_unix_warning ("munmap");
 416     }
 417   else
 418     {
 419       vec_free (p->free_indices);
 420       vec_free_h (v, pool_aligned_header_bytes);
 421     }
 422   return 0;
 423 }
 424
 425 static_always_inline uword
 426 pool_get_first_index (void *pool)
 427 {
 428   pool_header_t *h = pool_header (pool);
 429   return clib_bitmap_first_clear (h->free_bitmap);
 430 }
 431
 432 static_always_inline uword
 433 pool_get_next_index (void *pool, uword last)
 434 {
 435   pool_header_t *h = pool_header (pool);
 436   return clib_bitmap_next_clear (h->free_bitmap, last + 1);
 437 }
 438
 439 /** Free a pool. */
 440 #define pool_free(p) (p) = _pool_free(p)
 441
 442 /** Optimized iteration through pool.
 443
 444     @param LO pointer to first element in chunk
 445     @param HI pointer to last element in chunk
 446     @param POOL pool to iterate across
 447     @param BODY operation to perform
 448
 449     Optimized version which assumes that BODY is smart enough to
 450     process multiple (LOW,HI) chunks. See also pool_foreach().
 451  */
 452 #define pool_foreach_region(LO,HI,POOL,BODY)                            \
 453 do {                                                                    \
 454   uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
 455   uword _pool_var (bl), * _pool_var (b);                                \
 456   pool_header_t * _pool_var (p);                                        \
 457                                                                         \
 458   _pool_var (p) = pool_header (POOL);                                   \
 459   _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0;              \
 460   _pool_var (bl) = vec_len (_pool_var (b));                             \
 461   _pool_var (len) = vec_len (POOL);                                     \
 462   _pool_var (lo) = 0;                                                   \
 463                                                                         \
 464   for (_pool_var (i) = 0;                                               \
 465        _pool_var (i) <= _pool_var (bl);                                 \
 466        _pool_var (i)++)                                                 \
 467     {                                                                   \
 468       uword _pool_var (m), _pool_var (f);                               \
 469       _pool_var (m) = (_pool_var (i) < _pool_var (bl)                   \
 470                        ? _pool_var (b) [_pool_var (i)]                  \
 471                        : 1);                                            \
 472       while (_pool_var (m) != 0)                                        \
 473         {                                                               \
 474           _pool_var (f) = first_set (_pool_var (m));                    \
 475           _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0])     \
 476                             + min_log2 (_pool_var (f)));                \
 477           _pool_var (hi) = (_pool_var (i) < _pool_var (bl)              \
 478                             ? _pool_var (hi) : _pool_var (len));        \
 479           _pool_var (m) ^= _pool_var (f);                               \
 480           if (_pool_var (hi) > _pool_var (lo))                          \
 481             {                                                           \
 482               (LO) = _pool_var (lo);                                    \
 483               (HI) = _pool_var (hi);                                    \
 484               do { BODY; } while (0);                                   \
 485             }                                                           \
 486           _pool_var (lo) = _pool_var (hi) + 1;                          \
 487         }                                                               \
 488     }                                                                   \
 489 } while (0)
 490
 491 /** Iterate through pool.
 492
 493     @param VAR A variable of same type as pool vector to be used as an
 494                iterator.
 495     @param POOL The pool to iterate across.
 496     @param BODY The operation to perform, typically a code block. See
 497                 the example below.
 498
 499     This macro will call @c BODY with each active pool element.
 500
 501     It is a bad idea to allocate or free pool element from within
 502     @c pool_foreach. Build a vector of indices and dispose of them later.
 503     Or call pool_flush.
 504
 505
 506     @par Example
 507     @code{.c}
 508     proc_t *procs;   // a pool of processes.
 509     proc_t *proc;    // pointer to one process; used as the iterator.
 510
 511     pool_foreach (proc, procs, ({
 512         if (proc->state != PROC_STATE_RUNNING)
 513             continue;
 514
 515         // check a running proc in some way
 516         ...
 517     }));
 518     @endcode
 519
 520     @warning Because @c pool_foreach is a macro, syntax errors can be
 521     difficult to find inside @c BODY, let alone actual code bugs. One
 522     can temporarily split a complex @c pool_foreach into a trivial
 523     @c pool_foreach which builds a vector of active indices, and a
 524     vec_foreach() (or plain for-loop) to walk the active index vector.
 525  */
 526
 527 #define pool_foreach(VAR,POOL)                                          \
 528   if (POOL)                                                             \
 529     for (VAR = POOL + pool_get_first_index (POOL);                      \
 530          VAR < vec_end (POOL);                                          \
 531          VAR = POOL + pool_get_next_index (POOL, VAR - POOL))
 532
 533 #define pool_foreach_old(VAR,POOL,BODY)                                 \
 534   pool_foreach(VAR,POOL)                                                \
 535    { BODY; }
 536
 537 /** Returns pointer to element at given index.
 538
 539     ASSERTs that the supplied index is valid.
 540     Even though one can write correct code of the form
 541     @code
 542         p = pool_base + index;
 543     @endcode
 544     use of @c pool_elt_at_index is strongly suggested.
 545  */
 546 #define pool_elt_at_index(p,i)                  \
 547 ({                                              \
 548   typeof (p) _e = (p) + (i);                    \
 549   ASSERT (! pool_is_free (p, _e));              \
 550   _e;                                           \
 551 })
 552
 553 /** Return next occupied pool index after @c i, useful for safe iteration. */
 554 #define pool_next_index(P,I)                                            \
 555 ({                                                                      \
 556   pool_header_t * _pool_var (p) = pool_header (P);                      \
 557   uword _pool_var (rv) = (I) + 1;                                       \
 558                                                                         \
 559   _pool_var(rv) =                                                       \
 560     (_pool_var (rv) < vec_len (P) ?                                     \
 561      clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
 562      : ~0);                                                             \
 563   _pool_var(rv) =                                                       \
 564     (_pool_var (rv) < vec_len (P) ?                                     \
 565      _pool_var (rv) : ~0);                                              \
 566   _pool_var(rv);                                                        \
 567 })
 568
 569 #define pool_foreach_index(i,v)         \
 570   if (v)                                        \
 571     for (i = pool_get_first_index (v);          \
 572          i < vec_len (v);                       \
 573          i = pool_get_next_index (v, i))        \
 574
 575 /** Iterate pool by index. */
 576 #define pool_foreach_index_old(i,v,body)                \
 577   pool_foreach_index (i,v)                      \
 578         { body; }
 579
 580 /**
 581  * @brief Remove all elements from a pool in a safe way
 582  *
 583  * @param VAR each element in the pool
 584  * @param POOL The pool to flush
 585  * @param BODY The actions to perform on each element before it is returned to
 586  *        the pool. i.e. before it is 'freed'
 587  */
 588 #define pool_flush(VAR, POOL, BODY)                     \
 589 {                                                       \
 590   uword *_pool_var(ii), *_pool_var(dv) = NULL;          \
 591                                                         \
 592   pool_foreach((VAR), (POOL))                          \
 593   {                                                     \
 594     vec_add1(_pool_var(dv), (VAR) - (POOL));            \
 595   }                                                     \
 596   vec_foreach(_pool_var(ii), _pool_var(dv))             \
 597   {                                                     \
 598     (VAR) = pool_elt_at_index((POOL), *_pool_var(ii));  \
 599     do { BODY; } while (0);                             \
 600     pool_put((POOL), (VAR));                            \
 601   }                                                     \
 602   vec_free(_pool_var(dv));                              \
 603 }
 604
 605 #endif /* included_pool_h */
 606
 607 /*
 608  * fd.io coding-style-patch-verification: ON
 609  *
 610  * Local Variables:
 611  * eval: (c-set-style "gnu")
 612  * End:
 613  */