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       /*
 177        * Space left at end of vector?
 178        * Fixed-size pools have max_elts set non-zero,
 179        */
 180       if (p->max_elts == 0)
 181         n_free += vec_capacity (v, sizeof (p[0])) - vec_len (v);
 182     }
 183
 184   return n_free;
 185 }
 186
 187 /** Allocate an object E from a pool P (general version).
 188
 189    First search free list.  If nothing is free extend vector of objects.
 190 */
 191 #define _pool_get_aligned_internal_numa(P,E,A,Z,N)                      \
 192 do {                                                                    \
 193   pool_header_t * _pool_var (p) = pool_header (P);                      \
 194   uword _pool_var (l);                                                  \
 195                                                                         \
 196   STATIC_ASSERT(A==0 || ((A % sizeof(P[0]))==0)                         \
 197                 || ((sizeof(P[0]) % A) == 0),                           \
 198                 "Pool aligned alloc of incorrectly sized object");      \
 199   _pool_var (l) = 0;                                                    \
 200   if (P)                                                                \
 201     _pool_var (l) = vec_len (_pool_var (p)->free_indices);              \
 202                                                                         \
 203   if (_pool_var (l) > 0)                                                \
 204     {                                                                   \
 205       /* Return free element from free list. */                         \
 206       uword _pool_var (i) =                                             \
 207         _pool_var (p)->free_indices[_pool_var (l) - 1];                 \
 208       (E) = (P) + _pool_var (i);                                        \
 209       _pool_var (p)->free_bitmap =                                      \
 210         clib_bitmap_andnoti_notrim (_pool_var (p)->free_bitmap,         \
 211                                      _pool_var (i));                    \
 212       _vec_len (_pool_var (p)->free_indices) = _pool_var (l) - 1;       \
 213       CLIB_MEM_UNPOISON((E), sizeof((E)[0]));                           \
 214     }                                                                   \
 215   else                                                                  \
 216     {                                                                   \
 217       /* fixed-size, preallocated pools cannot expand */                \
 218       if ((P) && _pool_var(p)->max_elts)                                \
 219         {                                                               \
 220           clib_warning ("can't expand fixed-size pool");                \
 221           os_out_of_memory();                                           \
 222         }                                                               \
 223       /* Nothing on free list, make a new element and return it. */     \
 224       P = _vec_resize_numa (P,                                          \
 225                        /* length_increment */ 1,                        \
 226                        /* new size */ (vec_len (P) + 1) * sizeof (P[0]), \
 227                        pool_aligned_header_bytes,                       \
 228                        /* align */ (A),                                 \
 229                        /* numa */ (N));                                 \
 230       E = vec_end (P) - 1;                                              \
 231     }                                                                   \
 232   if (Z)                                                                \
 233     memset(E, 0, sizeof(*E));                                           \
 234 } while (0)
 235
 236 #define pool_get_aligned_zero_numa(P,E,A,Z,S) \
 237   _pool_get_aligned_internal_numa(P,E,A,Z,S)
 238
 239 #define pool_get_aligned_numa(P,E,A,S) \
 240   _pool_get_aligned_internal_numa(P,E,A,0/*zero*/,S)
 241
 242 #define pool_get_numa(P,E,S) \
 243   _pool_get_aligned_internal_numa(P,E,0/*align*/,0/*zero*/,S)
 244
 245 #define _pool_get_aligned_internal(P,E,A,Z) \
 246   _pool_get_aligned_internal_numa(P,E,A,Z,VEC_NUMA_UNSPECIFIED)
 247
 248 /** Allocate an object E from a pool P with alignment A */
 249 #define pool_get_aligned(P,E,A) _pool_get_aligned_internal(P,E,A,0)
 250
 251 /** Allocate an object E from a pool P with alignment A and zero it */
 252 #define pool_get_aligned_zero(P,E,A) _pool_get_aligned_internal(P,E,A,1)
 253
 254 /** Allocate an object E from a pool P (unspecified alignment). */
 255 #define pool_get(P,E) pool_get_aligned(P,E,0)
 256
 257 /** Allocate an object E from a pool P and zero it */
 258 #define pool_get_zero(P,E) pool_get_aligned_zero(P,E,0)
 259
 260 /** See if pool_get will expand the pool or not */
 261 #define pool_get_aligned_will_expand(P,YESNO,A)                         \
 262 do {                                                                    \
 263   pool_header_t * _pool_var (p) = pool_header (P);                      \
 264   uword _pool_var (l);                                                  \
 265                                                                         \
 266   _pool_var (l) = 0;                                                    \
 267   if (P)                                                                \
 268     {                                                                   \
 269       if (_pool_var (p)->max_elts)                                      \
 270         _pool_var (l) = _pool_var (p)->max_elts;                        \
 271       else                                                              \
 272         _pool_var (l) = vec_len (_pool_var (p)->free_indices);          \
 273     }                                                                   \
 274                                                                         \
 275   /* Free elements, certainly won't expand */                           \
 276   if (_pool_var (l) > 0)                                                \
 277       YESNO=0;                                                          \
 278   else                                                                  \
 279     {                                                                   \
 280       /* Nothing on free list, make a new element and return it. */     \
 281       YESNO = _vec_resize_will_expand                                   \
 282         (P,                                                             \
 283          /* length_increment */ 1,                                      \
 284          /* new size */ (vec_len (P) + 1) * sizeof (P[0]),              \
 285          pool_aligned_header_bytes,                                     \
 286          /* align */ (A));                                              \
 287     }                                                                   \
 288 } while (0)
 289
 290 /** See if pool_put will expand free_bitmap or free_indices or not */
 291 #define pool_put_will_expand(P, E, YESNO)                                     \
 292   do                                                                          \
 293     {                                                                         \
 294       pool_header_t *_pool_var (p) = pool_header (P);                         \
 295                                                                               \
 296       uword _pool_var (i) = (E) - (P);                                        \
 297       /* free_bitmap or free_indices may expand. */                           \
 298       YESNO =                                                                 \
 299         clib_bitmap_will_expand (_pool_var (p)->free_bitmap, _pool_var (i));  \
 300                                                                               \
 301       YESNO += _vec_resize_will_expand (                                      \
 302         _pool_var (p)->free_indices, 1,                                       \
 303         (vec_len (_pool_var (p)->free_indices) + 1) *                         \
 304           sizeof (_pool_var (p)->free_indices[0]),                            \
 305         0, 0);                                                                \
 306     }                                                                         \
 307   while (0)
 308
 309 /** Tell the caller if pool get will expand the pool */
 310 #define pool_get_will_expand(P,YESNO) pool_get_aligned_will_expand(P,YESNO,0)
 311
 312 /** Use free bitmap to query whether given element is free. */
 313 #define pool_is_free(P,E)                                               \
 314 ({                                                                      \
 315   pool_header_t * _pool_var (p) = pool_header (P);                      \
 316   uword _pool_var (i) = (E) - (P);                                      \
 317   (_pool_var (i) < vec_len (P)) ? clib_bitmap_get (_pool_var (p)->free_bitmap, _pool_i) : 1; \
 318 })
 319
 320 /** Use free bitmap to query whether given index is free */
 321 #define pool_is_free_index(P,I) pool_is_free((P),(P)+(I))
 322
 323 /** Free an object E in pool P. */
 324 #define pool_put(P, E)                                                        \
 325   do                                                                          \
 326     {                                                                         \
 327       typeof (P) _pool_var (p__) = (P);                                       \
 328       typeof (E) _pool_var (e__) = (E);                                       \
 329       pool_header_t *_pool_var (p) = pool_header (_pool_var (p__));           \
 330       uword _pool_var (l) = _pool_var (e__) - _pool_var (p__);                \
 331       if (_pool_var (p)->max_elts == 0)                                       \
 332         ASSERT (vec_is_member (_pool_var (p__), _pool_var (e__)));            \
 333       ASSERT (!pool_is_free (_pool_var (p__), _pool_var (e__)));              \
 334                                                                               \
 335       /* Add element to free bitmap and to free list. */                      \
 336       _pool_var (p)->free_bitmap =                                            \
 337         clib_bitmap_ori_notrim (_pool_var (p)->free_bitmap, _pool_var (l));   \
 338                                                                               \
 339       /* Preallocated pool? */                                                \
 340       if (_pool_var (p)->max_elts)                                            \
 341         {                                                                     \
 342           ASSERT (_pool_var (l) < _pool_var (p)->max_elts);                   \
 343           _pool_var (p)                                                       \
 344             ->free_indices[_vec_len (_pool_var (p)->free_indices)] =          \
 345             _pool_var (l);                                                    \
 346           _vec_len (_pool_var (p)->free_indices) += 1;                        \
 347         }                                                                     \
 348       else                                                                    \
 349         vec_add1 (_pool_var (p)->free_indices, _pool_var (l));                \
 350                                                                               \
 351       CLIB_MEM_POISON (_pool_var (e__), sizeof (_pool_var (e__)[0]));         \
 352     }                                                                         \
 353   while (0)
 354
 355 /** Free pool element with given index. */
 356 #define pool_put_index(p,i)                     \
 357 do {                                            \
 358   typeof (p) _e = (p) + (i);                    \
 359   pool_put (p, _e);                             \
 360 } while (0)
 361
 362 /** Allocate N more free elements to pool (general version). */
 363 #define pool_alloc_aligned(P,N,A)                                       \
 364 do {                                                                    \
 365   pool_header_t * _p;                                                   \
 366                                                                         \
 367   if ((P))                                                              \
 368     {                                                                   \
 369       _p = pool_header (P);                                             \
 370       if (_p->max_elts)                                                 \
 371         {                                                               \
 372            clib_warning ("Can't expand fixed-size pool");               \
 373            os_out_of_memory();                                          \
 374         }                                                               \
 375     }                                                                   \
 376                                                                         \
 377   (P) = _vec_resize ((P), 0, (vec_len (P) + (N)) * sizeof (P[0]),       \
 378                      pool_aligned_header_bytes,                         \
 379                      (A));                                              \
 380   _p = pool_header (P);                                                 \
 381   vec_resize (_p->free_indices, (N));                                   \
 382   _vec_len (_p->free_indices) -= (N);                                   \
 383 } while (0)
 384
 385 /** Allocate N more free elements to pool (unspecified alignment). */
 386 #define pool_alloc(P,N) pool_alloc_aligned(P,N,0)
 387
 388 /**
 389  * Return copy of pool with alignment
 390  *
 391  * @param P pool to copy
 392  * @param A alignment (may be zero)
 393  * @return copy of pool
 394  */
 395 #define pool_dup_aligned(P, A)                                                \
 396   ({                                                                          \
 397     typeof (P) _pool_var (new) = 0;                                           \
 398     pool_header_t *_pool_var (ph), *_pool_var (new_ph);                       \
 399     u32 _pool_var (n) = pool_len (P);                                         \
 400     if ((P))                                                                  \
 401       {                                                                       \
 402         _pool_var (new) = _vec_resize (_pool_var (new), _pool_var (n),        \
 403                                        _pool_var (n) * sizeof ((P)[0]),       \
 404                                        pool_aligned_header_bytes, (A));       \
 405         CLIB_MEM_OVERFLOW_PUSH ((P), _pool_var (n) * sizeof ((P)[0]));        \
 406         clib_memcpy_fast (_pool_var (new), (P),                               \
 407                           _pool_var (n) * sizeof ((P)[0]));                   \
 408         CLIB_MEM_OVERFLOW_POP ();                                             \
 409         _pool_var (ph) = pool_header (P);                                     \
 410         _pool_var (new_ph) = pool_header (_pool_var (new));                   \
 411         _pool_var (new_ph)->free_bitmap =                                     \
 412           clib_bitmap_dup (_pool_var (ph)->free_bitmap);                      \
 413         _pool_var (new_ph)->free_indices =                                    \
 414           vec_dup (_pool_var (ph)->free_indices);                             \
 415         _pool_var (new_ph)->max_elts = _pool_var (ph)->max_elts;              \
 416       }                                                                       \
 417     _pool_var (new);                                                          \
 418   })
 419
 420 /**
 421  * Return copy of pool without alignment
 422  *
 423  * @param P pool to copy
 424  * @return copy of pool
 425  */
 426 #define pool_dup(P) pool_dup_aligned(P,0)
 427
 428 /** Low-level free pool operator (do not call directly). */
 429 always_inline void *
 430 _pool_free (void *v)
 431 {
 432   pool_header_t *p = pool_header (v);
 433   if (!v)
 434     return v;
 435   clib_bitmap_free (p->free_bitmap);
 436
 437   if (p->max_elts)
 438     {
 439       int rv;
 440
 441       rv = munmap (p->mmap_base, p->mmap_size);
 442       if (rv)
 443         clib_unix_warning ("munmap");
 444     }
 445   else
 446     {
 447       vec_free (p->free_indices);
 448       vec_free_h (v, pool_aligned_header_bytes);
 449     }
 450   return 0;
 451 }
 452
 453 static_always_inline uword
 454 pool_get_first_index (void *pool)
 455 {
 456   pool_header_t *h = pool_header (pool);
 457   return clib_bitmap_first_clear (h->free_bitmap);
 458 }
 459
 460 static_always_inline uword
 461 pool_get_next_index (void *pool, uword last)
 462 {
 463   pool_header_t *h = pool_header (pool);
 464   return clib_bitmap_next_clear (h->free_bitmap, last + 1);
 465 }
 466
 467 /** Free a pool. */
 468 #define pool_free(p) (p) = _pool_free(p)
 469
 470 /** Optimized iteration through pool.
 471
 472     @param LO pointer to first element in chunk
 473     @param HI pointer to last element in chunk
 474     @param POOL pool to iterate across
 475     @param BODY operation to perform
 476
 477     Optimized version which assumes that BODY is smart enough to
 478     process multiple (LOW,HI) chunks. See also pool_foreach().
 479  */
 480 #define pool_foreach_region(LO,HI,POOL,BODY)                            \
 481 do {                                                                    \
 482   uword _pool_var (i), _pool_var (lo), _pool_var (hi), _pool_var (len); \
 483   uword _pool_var (bl), * _pool_var (b);                                \
 484   pool_header_t * _pool_var (p);                                        \
 485                                                                         \
 486   _pool_var (p) = pool_header (POOL);                                   \
 487   _pool_var (b) = (POOL) ? _pool_var (p)->free_bitmap : 0;              \
 488   _pool_var (bl) = vec_len (_pool_var (b));                             \
 489   _pool_var (len) = vec_len (POOL);                                     \
 490   _pool_var (lo) = 0;                                                   \
 491                                                                         \
 492   for (_pool_var (i) = 0;                                               \
 493        _pool_var (i) <= _pool_var (bl);                                 \
 494        _pool_var (i)++)                                                 \
 495     {                                                                   \
 496       uword _pool_var (m), _pool_var (f);                               \
 497       _pool_var (m) = (_pool_var (i) < _pool_var (bl)                   \
 498                        ? _pool_var (b) [_pool_var (i)]                  \
 499                        : 1);                                            \
 500       while (_pool_var (m) != 0)                                        \
 501         {                                                               \
 502           _pool_var (f) = first_set (_pool_var (m));                    \
 503           _pool_var (hi) = (_pool_var (i) * BITS (_pool_var (b)[0])     \
 504                             + min_log2 (_pool_var (f)));                \
 505           _pool_var (hi) = (_pool_var (i) < _pool_var (bl)              \
 506                             ? _pool_var (hi) : _pool_var (len));        \
 507           _pool_var (m) ^= _pool_var (f);                               \
 508           if (_pool_var (hi) > _pool_var (lo))                          \
 509             {                                                           \
 510               (LO) = _pool_var (lo);                                    \
 511               (HI) = _pool_var (hi);                                    \
 512               do { BODY; } while (0);                                   \
 513             }                                                           \
 514           _pool_var (lo) = _pool_var (hi) + 1;                          \
 515         }                                                               \
 516     }                                                                   \
 517 } while (0)
 518
 519 /** Iterate through pool.
 520
 521     @param VAR A variable of same type as pool vector to be used as an
 522                iterator.
 523     @param POOL The pool to iterate across.
 524     @param BODY The operation to perform, typically a code block. See
 525                 the example below.
 526
 527     This macro will call @c BODY with each active pool element.
 528
 529     It is a bad idea to allocate or free pool element from within
 530     @c pool_foreach. Build a vector of indices and dispose of them later.
 531     Or call pool_flush.
 532
 533
 534     @par Example
 535     @code{.c}
 536     proc_t *procs;   // a pool of processes.
 537     proc_t *proc;    // pointer to one process; used as the iterator.
 538
 539     pool_foreach (proc, procs, ({
 540         if (proc->state != PROC_STATE_RUNNING)
 541             continue;
 542
 543         // check a running proc in some way
 544         ...
 545     }));
 546     @endcode
 547
 548     @warning Because @c pool_foreach is a macro, syntax errors can be
 549     difficult to find inside @c BODY, let alone actual code bugs. One
 550     can temporarily split a complex @c pool_foreach into a trivial
 551     @c pool_foreach which builds a vector of active indices, and a
 552     vec_foreach() (or plain for-loop) to walk the active index vector.
 553  */
 554
 555 #define pool_foreach(VAR,POOL)                                          \
 556   if (POOL)                                                             \
 557     for (VAR = POOL + pool_get_first_index (POOL);                      \
 558          VAR < vec_end (POOL);                                          \
 559          VAR = POOL + pool_get_next_index (POOL, VAR - POOL))
 560
 561 /** Returns pointer to element at given index.
 562
 563     ASSERTs that the supplied index is valid.
 564     Even though one can write correct code of the form
 565     @code
 566         p = pool_base + index;
 567     @endcode
 568     use of @c pool_elt_at_index is strongly suggested.
 569  */
 570 #define pool_elt_at_index(p,i)                  \
 571 ({                                              \
 572   typeof (p) _e = (p) + (i);                    \
 573   ASSERT (! pool_is_free (p, _e));              \
 574   _e;                                           \
 575 })
 576
 577 /** Return next occupied pool index after @c i, useful for safe iteration. */
 578 #define pool_next_index(P,I)                                            \
 579 ({                                                                      \
 580   pool_header_t * _pool_var (p) = pool_header (P);                      \
 581   uword _pool_var (rv) = (I) + 1;                                       \
 582                                                                         \
 583   _pool_var(rv) =                                                       \
 584     (_pool_var (rv) < vec_len (P) ?                                     \
 585      clib_bitmap_next_clear (_pool_var (p)->free_bitmap, _pool_var(rv)) \
 586      : ~0);                                                             \
 587   _pool_var(rv) =                                                       \
 588     (_pool_var (rv) < vec_len (P) ?                                     \
 589      _pool_var (rv) : ~0);                                              \
 590   _pool_var(rv);                                                        \
 591 })
 592
 593 #define pool_foreach_index(i,v)         \
 594   if (v)                                        \
 595     for (i = pool_get_first_index (v);          \
 596          i < vec_len (v);                       \
 597          i = pool_get_next_index (v, i))        \
 598
 599 /**
 600  * @brief Remove all elements from a pool in a safe way
 601  *
 602  * @param VAR each element in the pool
 603  * @param POOL The pool to flush
 604  * @param BODY The actions to perform on each element before it is returned to
 605  *        the pool. i.e. before it is 'freed'
 606  */
 607 #define pool_flush(VAR, POOL, BODY)                     \
 608 {                                                       \
 609   uword *_pool_var(ii), *_pool_var(dv) = NULL;          \
 610                                                         \
 611   pool_foreach((VAR), (POOL))                          \
 612   {                                                     \
 613     vec_add1(_pool_var(dv), (VAR) - (POOL));            \
 614   }                                                     \
 615   vec_foreach(_pool_var(ii), _pool_var(dv))             \
 616   {                                                     \
 617     (VAR) = pool_elt_at_index((POOL), *_pool_var(ii));  \
 618     do { BODY; } while (0);                             \
 619     pool_put((POOL), (VAR));                            \
 620   }                                                     \
 621   vec_free(_pool_var(dv));                              \
 622 }
 623
 624 #endif /* included_pool_h */
 625
 626 /*
 627  * fd.io coding-style-patch-verification: ON
 628  *
 629  * Local Variables:
 630  * eval: (c-set-style "gnu")
 631  * End:
 632  */