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