DPDK  18.05.1
rte_bitmap.h
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1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #ifndef __INCLUDE_RTE_BITMAP_H__
6 #define __INCLUDE_RTE_BITMAP_H__
7 
8 #ifdef __cplusplus
9 extern "C" {
10 #endif
11 
38 #include <string.h>
39 #include <rte_common.h>
40 #include <rte_config.h>
41 #include <rte_debug.h>
42 #include <rte_memory.h>
43 #include <rte_branch_prediction.h>
44 #include <rte_prefetch.h>
45 
46 #ifndef RTE_BITMAP_OPTIMIZATIONS
47 #define RTE_BITMAP_OPTIMIZATIONS 1
48 #endif
49 
50 /* Slab */
51 #define RTE_BITMAP_SLAB_BIT_SIZE 64
52 #define RTE_BITMAP_SLAB_BIT_SIZE_LOG2 6
53 #define RTE_BITMAP_SLAB_BIT_MASK (RTE_BITMAP_SLAB_BIT_SIZE - 1)
54 
55 /* Cache line (CL) */
56 #define RTE_BITMAP_CL_BIT_SIZE (RTE_CACHE_LINE_SIZE * 8)
57 #define RTE_BITMAP_CL_BIT_SIZE_LOG2 (RTE_CACHE_LINE_SIZE_LOG2 + 3)
58 #define RTE_BITMAP_CL_BIT_MASK (RTE_BITMAP_CL_BIT_SIZE - 1)
59 
60 #define RTE_BITMAP_CL_SLAB_SIZE (RTE_BITMAP_CL_BIT_SIZE / RTE_BITMAP_SLAB_BIT_SIZE)
61 #define RTE_BITMAP_CL_SLAB_SIZE_LOG2 (RTE_BITMAP_CL_BIT_SIZE_LOG2 - RTE_BITMAP_SLAB_BIT_SIZE_LOG2)
62 #define RTE_BITMAP_CL_SLAB_MASK (RTE_BITMAP_CL_SLAB_SIZE - 1)
63 
65 struct rte_bitmap {
66  /* Context for array1 and array2 */
67  uint64_t *array1;
68  uint64_t *array2;
69  uint32_t array1_size;
70  uint32_t array2_size;
72  /* Context for the "scan next" operation */
73  uint32_t index1;
74  uint32_t offset1;
75  uint32_t index2;
76  uint32_t go2;
78  /* Storage space for array1 and array2 */
79  uint8_t memory[];
80 };
81 
82 static inline void
83 __rte_bitmap_index1_inc(struct rte_bitmap *bmp)
84 {
85  bmp->index1 = (bmp->index1 + 1) & (bmp->array1_size - 1);
86 }
87 
88 static inline uint64_t
89 __rte_bitmap_mask1_get(struct rte_bitmap *bmp)
90 {
91  return (~1lu) << bmp->offset1;
92 }
93 
94 static inline void
95 __rte_bitmap_index2_set(struct rte_bitmap *bmp)
96 {
97  bmp->index2 = (((bmp->index1 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2) + bmp->offset1) << RTE_BITMAP_CL_SLAB_SIZE_LOG2);
98 }
99 
100 #if RTE_BITMAP_OPTIMIZATIONS
101 
102 static inline int
103 rte_bsf64(uint64_t slab, uint32_t *pos)
104 {
105  if (likely(slab == 0)) {
106  return 0;
107  }
108 
109  *pos = __builtin_ctzll(slab);
110  return 1;
111 }
112 
113 #else
114 
115 static inline int
116 rte_bsf64(uint64_t slab, uint32_t *pos)
117 {
118  uint64_t mask;
119  uint32_t i;
120 
121  if (likely(slab == 0)) {
122  return 0;
123  }
124 
125  for (i = 0, mask = 1; i < RTE_BITMAP_SLAB_BIT_SIZE; i ++, mask <<= 1) {
126  if (unlikely(slab & mask)) {
127  *pos = i;
128  return 1;
129  }
130  }
131 
132  return 0;
133 }
134 
135 #endif
136 
137 static inline uint32_t
138 __rte_bitmap_get_memory_footprint(uint32_t n_bits,
139  uint32_t *array1_byte_offset, uint32_t *array1_slabs,
140  uint32_t *array2_byte_offset, uint32_t *array2_slabs)
141 {
142  uint32_t n_slabs_context, n_slabs_array1, n_cache_lines_context_and_array1;
143  uint32_t n_cache_lines_array2;
144  uint32_t n_bytes_total;
145 
146  n_cache_lines_array2 = (n_bits + RTE_BITMAP_CL_BIT_SIZE - 1) / RTE_BITMAP_CL_BIT_SIZE;
147  n_slabs_array1 = (n_cache_lines_array2 + RTE_BITMAP_SLAB_BIT_SIZE - 1) / RTE_BITMAP_SLAB_BIT_SIZE;
148  n_slabs_array1 = rte_align32pow2(n_slabs_array1);
149  n_slabs_context = (sizeof(struct rte_bitmap) + (RTE_BITMAP_SLAB_BIT_SIZE / 8) - 1) / (RTE_BITMAP_SLAB_BIT_SIZE / 8);
150  n_cache_lines_context_and_array1 = (n_slabs_context + n_slabs_array1 + RTE_BITMAP_CL_SLAB_SIZE - 1) / RTE_BITMAP_CL_SLAB_SIZE;
151  n_bytes_total = (n_cache_lines_context_and_array1 + n_cache_lines_array2) * RTE_CACHE_LINE_SIZE;
152 
153  if (array1_byte_offset) {
154  *array1_byte_offset = n_slabs_context * (RTE_BITMAP_SLAB_BIT_SIZE / 8);
155  }
156  if (array1_slabs) {
157  *array1_slabs = n_slabs_array1;
158  }
159  if (array2_byte_offset) {
160  *array2_byte_offset = n_cache_lines_context_and_array1 * RTE_CACHE_LINE_SIZE;
161  }
162  if (array2_slabs) {
163  *array2_slabs = n_cache_lines_array2 * RTE_BITMAP_CL_SLAB_SIZE;
164  }
165 
166  return n_bytes_total;
167 }
168 
169 static inline void
170 __rte_bitmap_scan_init(struct rte_bitmap *bmp)
171 {
172  bmp->index1 = bmp->array1_size - 1;
173  bmp->offset1 = RTE_BITMAP_SLAB_BIT_SIZE - 1;
174  __rte_bitmap_index2_set(bmp);
175  bmp->index2 += RTE_BITMAP_CL_SLAB_SIZE;
176 
177  bmp->go2 = 0;
178 }
179 
188 static inline uint32_t
189 rte_bitmap_get_memory_footprint(uint32_t n_bits) {
190  /* Check input arguments */
191  if (n_bits == 0) {
192  return 0;
193  }
194 
195  return __rte_bitmap_get_memory_footprint(n_bits, NULL, NULL, NULL, NULL);
196 }
197 
210 static inline struct rte_bitmap *
211 rte_bitmap_init(uint32_t n_bits, uint8_t *mem, uint32_t mem_size)
212 {
213  struct rte_bitmap *bmp;
214  uint32_t array1_byte_offset, array1_slabs, array2_byte_offset, array2_slabs;
215  uint32_t size;
216 
217  /* Check input arguments */
218  if (n_bits == 0) {
219  return NULL;
220  }
221 
222  if ((mem == NULL) || (((uintptr_t) mem) & RTE_CACHE_LINE_MASK)) {
223  return NULL;
224  }
225 
226  size = __rte_bitmap_get_memory_footprint(n_bits,
227  &array1_byte_offset, &array1_slabs,
228  &array2_byte_offset, &array2_slabs);
229  if (size < mem_size) {
230  return NULL;
231  }
232 
233  /* Setup bitmap */
234  memset(mem, 0, size);
235  bmp = (struct rte_bitmap *) mem;
236 
237  bmp->array1 = (uint64_t *) &mem[array1_byte_offset];
238  bmp->array1_size = array1_slabs;
239  bmp->array2 = (uint64_t *) &mem[array2_byte_offset];
240  bmp->array2_size = array2_slabs;
241 
242  __rte_bitmap_scan_init(bmp);
243 
244  return bmp;
245 }
246 
255 static inline int
256 rte_bitmap_free(struct rte_bitmap *bmp)
257 {
258  /* Check input arguments */
259  if (bmp == NULL) {
260  return -1;
261  }
262 
263  return 0;
264 }
265 
272 static inline void
273 rte_bitmap_reset(struct rte_bitmap *bmp)
274 {
275  memset(bmp->array1, 0, bmp->array1_size * sizeof(uint64_t));
276  memset(bmp->array2, 0, bmp->array2_size * sizeof(uint64_t));
277  __rte_bitmap_scan_init(bmp);
278 }
279 
290 static inline void
291 rte_bitmap_prefetch0(struct rte_bitmap *bmp, uint32_t pos)
292 {
293  uint64_t *slab2;
294  uint32_t index2;
295 
296  index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
297  slab2 = bmp->array2 + index2;
298  rte_prefetch0((void *) slab2);
299 }
300 
311 static inline uint64_t
312 rte_bitmap_get(struct rte_bitmap *bmp, uint32_t pos)
313 {
314  uint64_t *slab2;
315  uint32_t index2, offset2;
316 
317  index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
318  offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK;
319  slab2 = bmp->array2 + index2;
320  return (*slab2) & (1lu << offset2);
321 }
322 
331 static inline void
332 rte_bitmap_set(struct rte_bitmap *bmp, uint32_t pos)
333 {
334  uint64_t *slab1, *slab2;
335  uint32_t index1, index2, offset1, offset2;
336 
337  /* Set bit in array2 slab and set bit in array1 slab */
338  index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
339  offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK;
340  index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2);
341  offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK;
342  slab2 = bmp->array2 + index2;
343  slab1 = bmp->array1 + index1;
344 
345  *slab2 |= 1lu << offset2;
346  *slab1 |= 1lu << offset1;
347 }
348 
359 static inline void
360 rte_bitmap_set_slab(struct rte_bitmap *bmp, uint32_t pos, uint64_t slab)
361 {
362  uint64_t *slab1, *slab2;
363  uint32_t index1, index2, offset1;
364 
365  /* Set bits in array2 slab and set bit in array1 slab */
366  index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
367  index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2);
368  offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK;
369  slab2 = bmp->array2 + index2;
370  slab1 = bmp->array1 + index1;
371 
372  *slab2 |= slab;
373  *slab1 |= 1lu << offset1;
374 }
375 
376 static inline uint64_t
377 __rte_bitmap_line_not_empty(uint64_t *slab2)
378 {
379  uint64_t v1, v2, v3, v4;
380 
381  v1 = slab2[0] | slab2[1];
382  v2 = slab2[2] | slab2[3];
383  v3 = slab2[4] | slab2[5];
384  v4 = slab2[6] | slab2[7];
385  v1 |= v2;
386  v3 |= v4;
387 
388  return v1 | v3;
389 }
390 
399 static inline void
400 rte_bitmap_clear(struct rte_bitmap *bmp, uint32_t pos)
401 {
402  uint64_t *slab1, *slab2;
403  uint32_t index1, index2, offset1, offset2;
404 
405  /* Clear bit in array2 slab */
406  index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
407  offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK;
408  slab2 = bmp->array2 + index2;
409 
410  /* Return if array2 slab is not all-zeros */
411  *slab2 &= ~(1lu << offset2);
412  if (*slab2){
413  return;
414  }
415 
416  /* Check the entire cache line of array2 for all-zeros */
417  index2 &= ~ RTE_BITMAP_CL_SLAB_MASK;
418  slab2 = bmp->array2 + index2;
419  if (__rte_bitmap_line_not_empty(slab2)) {
420  return;
421  }
422 
423  /* The array2 cache line is all-zeros, so clear bit in array1 slab */
424  index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2);
425  offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK;
426  slab1 = bmp->array1 + index1;
427  *slab1 &= ~(1lu << offset1);
428 
429  return;
430 }
431 
432 static inline int
433 __rte_bitmap_scan_search(struct rte_bitmap *bmp)
434 {
435  uint64_t value1;
436  uint32_t i;
437 
438  /* Check current array1 slab */
439  value1 = bmp->array1[bmp->index1];
440  value1 &= __rte_bitmap_mask1_get(bmp);
441 
442  if (rte_bsf64(value1, &bmp->offset1)) {
443  return 1;
444  }
445 
446  __rte_bitmap_index1_inc(bmp);
447  bmp->offset1 = 0;
448 
449  /* Look for another array1 slab */
450  for (i = 0; i < bmp->array1_size; i ++, __rte_bitmap_index1_inc(bmp)) {
451  value1 = bmp->array1[bmp->index1];
452 
453  if (rte_bsf64(value1, &bmp->offset1)) {
454  return 1;
455  }
456  }
457 
458  return 0;
459 }
460 
461 static inline void
462 __rte_bitmap_scan_read_init(struct rte_bitmap *bmp)
463 {
464  __rte_bitmap_index2_set(bmp);
465  bmp->go2 = 1;
466  rte_prefetch1((void *)(bmp->array2 + bmp->index2 + 8));
467 }
468 
469 static inline int
470 __rte_bitmap_scan_read(struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab)
471 {
472  uint64_t *slab2;
473 
474  slab2 = bmp->array2 + bmp->index2;
475  for ( ; bmp->go2 ; bmp->index2 ++, slab2 ++, bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK) {
476  if (*slab2) {
477  *pos = bmp->index2 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
478  *slab = *slab2;
479 
480  bmp->index2 ++;
481  slab2 ++;
482  bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK;
483  return 1;
484  }
485  }
486 
487  return 0;
488 }
489 
510 static inline int
511 rte_bitmap_scan(struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab)
512 {
513  /* Return data from current array2 line if available */
514  if (__rte_bitmap_scan_read(bmp, pos, slab)) {
515  return 1;
516  }
517 
518  /* Look for non-empty array2 line */
519  if (__rte_bitmap_scan_search(bmp)) {
520  __rte_bitmap_scan_read_init(bmp);
521  __rte_bitmap_scan_read(bmp, pos, slab);
522  return 1;
523  }
524 
525  /* Empty bitmap */
526  return 0;
527 }
528 
529 #ifdef __cplusplus
530 }
531 #endif
532 
533 #endif /* __INCLUDE_RTE_BITMAP_H__ */
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