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lib/eal/include/rte_bitmap.h
584 строки
15 KB
Stephen Hemminger
bitmap: change return type of free function
11 ноя 2025, 17:19
11 ноя 2025, 17:19
874581d
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/* SPDX-License-Identifier: BSD-3-Clause * Copyright(c) 2010-2014 Intel Corporation */ #ifndef __INCLUDE_RTE_BITMAP_H__ #define __INCLUDE_RTE_BITMAP_H__ /** * @file * RTE Bitmap * * The bitmap component provides a mechanism to manage large arrays of bits * through bit get/set/clear and bit array scan operations. * * The bitmap scan operation is optimized for 64-bit CPUs using 64/128 byte cache * lines. The bitmap is hierarchically organized using two arrays (array1 and * array2), with each bit in array1 being associated with a full cache line * (512/1024 bits) of bitmap bits, which are stored in array2: the bit in array1 * is set only when there is at least one bit set within its associated array2 * bits, otherwise the bit in array1 is cleared. The read and write operations * for array1 and array2 are always done in slabs of 64 bits. * * This bitmap is not thread safe. For lock free operation on a specific bitmap * instance, a single writer thread performing bit set/clear operations is * allowed, only the writer thread can do bitmap scan operations, while there * can be several reader threads performing bit get operations in parallel with * the writer thread. When the use of locking primitives is acceptable, the * serialization of the bit set/clear and bitmap scan operations needs to be * enforced by the caller, while the bit get operation does not require locking * the bitmap. */ #include <string.h> #include <rte_common.h> #include <rte_config.h> #include <rte_debug.h> #include <rte_memory.h> #include <rte_branch_prediction.h> #include <rte_prefetch.h> #ifdef __cplusplus extern "C" { #endif /* Slab */ #define RTE_BITMAP_SLAB_BIT_SIZE 64 #define RTE_BITMAP_SLAB_BIT_SIZE_LOG2 6 #define RTE_BITMAP_SLAB_BIT_MASK (RTE_BITMAP_SLAB_BIT_SIZE - 1) /* Cache line (CL) */ #define RTE_BITMAP_CL_BIT_SIZE (RTE_CACHE_LINE_SIZE * 8) #define RTE_BITMAP_CL_BIT_SIZE_LOG2 (RTE_CACHE_LINE_SIZE_LOG2 + 3) #define RTE_BITMAP_CL_BIT_MASK (RTE_BITMAP_CL_BIT_SIZE - 1) #define RTE_BITMAP_CL_SLAB_SIZE (RTE_BITMAP_CL_BIT_SIZE / RTE_BITMAP_SLAB_BIT_SIZE) #define RTE_BITMAP_CL_SLAB_SIZE_LOG2 (RTE_BITMAP_CL_BIT_SIZE_LOG2 - RTE_BITMAP_SLAB_BIT_SIZE_LOG2) #define RTE_BITMAP_CL_SLAB_MASK (RTE_BITMAP_CL_SLAB_SIZE - 1) /** Bitmap data structure */ struct rte_bitmap { /* Context for array1 and array2 */ uint64_t *array1; /**< Bitmap array1 */ uint64_t *array2; /**< Bitmap array2 */ uint32_t array1_size; /**< Number of 64-bit slabs in array1 that are actually used */ uint32_t array2_size; /**< Number of 64-bit slabs in array2 */ /* Context for the "scan next" operation */ uint32_t index1; /**< Bitmap scan: Index of current array1 slab */ uint32_t offset1; /**< Bitmap scan: Offset of current bit within current array1 slab */ uint32_t index2; /**< Bitmap scan: Index of current array2 slab */ uint32_t go2; /**< Bitmap scan: Go/stop condition for current array2 cache line */ /* Storage space for array1 and array2 */ uint8_t memory[]; }; static inline void __rte_bitmap_index1_inc(struct rte_bitmap *bmp) { bmp->index1 = (bmp->index1 + 1) & (bmp->array1_size - 1); } static inline uint64_t __rte_bitmap_mask1_get(struct rte_bitmap *bmp) { return (~1llu) << bmp->offset1; } static inline void __rte_bitmap_index2_set(struct rte_bitmap *bmp) { bmp->index2 = (((bmp->index1 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2) + bmp->offset1) << RTE_BITMAP_CL_SLAB_SIZE_LOG2); } static inline uint32_t __rte_bitmap_get_memory_footprint(uint32_t n_bits, uint32_t *array1_byte_offset, uint32_t *array1_slabs, uint32_t *array2_byte_offset, uint32_t *array2_slabs) { uint32_t n_slabs_context, n_slabs_array1, n_cache_lines_context_and_array1; uint32_t n_cache_lines_array2; uint32_t n_bytes_total; n_cache_lines_array2 = (n_bits + RTE_BITMAP_CL_BIT_SIZE - 1) / RTE_BITMAP_CL_BIT_SIZE; n_slabs_array1 = (n_cache_lines_array2 + RTE_BITMAP_SLAB_BIT_SIZE - 1) / RTE_BITMAP_SLAB_BIT_SIZE; n_slabs_array1 = rte_align32pow2(n_slabs_array1); n_slabs_context = (sizeof(struct rte_bitmap) + (RTE_BITMAP_SLAB_BIT_SIZE / 8) - 1) / (RTE_BITMAP_SLAB_BIT_SIZE / 8); n_cache_lines_context_and_array1 = (n_slabs_context + n_slabs_array1 + RTE_BITMAP_CL_SLAB_SIZE - 1) / RTE_BITMAP_CL_SLAB_SIZE; n_bytes_total = (n_cache_lines_context_and_array1 + n_cache_lines_array2) * RTE_CACHE_LINE_SIZE; if (array1_byte_offset) { *array1_byte_offset = n_slabs_context * (RTE_BITMAP_SLAB_BIT_SIZE / 8); } if (array1_slabs) { *array1_slabs = n_slabs_array1; } if (array2_byte_offset) { *array2_byte_offset = n_cache_lines_context_and_array1 * RTE_CACHE_LINE_SIZE; } if (array2_slabs) { *array2_slabs = n_cache_lines_array2 * RTE_BITMAP_CL_SLAB_SIZE; } return n_bytes_total; } static inline void __rte_bitmap_scan_init(struct rte_bitmap *bmp) { bmp->index1 = bmp->array1_size - 1; bmp->offset1 = RTE_BITMAP_SLAB_BIT_SIZE - 1; __rte_bitmap_index2_set(bmp); bmp->index2 += RTE_BITMAP_CL_SLAB_SIZE; bmp->go2 = 0; } /** * Bitmap memory footprint calculation * * @param n_bits * Number of bits in the bitmap * @return * Bitmap memory footprint measured in bytes on success, 0 on error */ static inline uint32_t rte_bitmap_get_memory_footprint(uint32_t n_bits) { /* Check input arguments */ if (n_bits == 0) { return 0; } return __rte_bitmap_get_memory_footprint(n_bits, NULL, NULL, NULL, NULL); } /** * Bitmap initialization * * @param n_bits * Number of pre-allocated bits in array2. * @param mem * Base address of array1 and array2. * @param mem_size * Minimum expected size of bitmap. * @return * Handle to bitmap instance. */ static inline struct rte_bitmap * rte_bitmap_init(uint32_t n_bits, uint8_t *mem, uint32_t mem_size) { struct rte_bitmap *bmp; uint32_t array1_byte_offset, array1_slabs, array2_byte_offset, array2_slabs; uint32_t size; /* Check input arguments */ if (n_bits == 0) { return NULL; } if ((mem == NULL) || (((uintptr_t) mem) & RTE_CACHE_LINE_MASK)) { return NULL; } size = __rte_bitmap_get_memory_footprint(n_bits, &array1_byte_offset, &array1_slabs, &array2_byte_offset, &array2_slabs); if (size > mem_size) return NULL; /* Setup bitmap */ memset(mem, 0, size); bmp = (struct rte_bitmap *) mem; bmp->array1 = (uint64_t *) &mem[array1_byte_offset]; bmp->array1_size = array1_slabs; bmp->array2 = (uint64_t *) &mem[array2_byte_offset]; bmp->array2_size = array2_slabs; __rte_bitmap_scan_init(bmp); return bmp; } /** * Bitmap clear slab overhead bits. * * @param slabs * Slab array. * @param slab_size * Number of 64-bit slabs in the slabs array. * @param pos * The start bit position in the slabs to be cleared. */ static inline void __rte_bitmap_clear_slab_overhead_bits(uint64_t *slabs, uint32_t slab_size, uint32_t pos) { uint32_t i; uint32_t index = pos / RTE_BITMAP_SLAB_BIT_SIZE; uint32_t offset = pos & RTE_BITMAP_SLAB_BIT_MASK; if (offset) { for (i = offset; i < RTE_BITMAP_SLAB_BIT_SIZE; i++) slabs[index] &= ~(1llu << i); index++; } if (index < slab_size) memset(&slabs[index], 0, sizeof(slabs[0]) * (slab_size - index)); } /** * Bitmap initialization with all bits set * * @param n_bits * Number of pre-allocated bits in array2. * @param mem * Base address of array1 and array2. * @param mem_size * Minimum expected size of bitmap. * @return * Handle to bitmap instance. */ static inline struct rte_bitmap * rte_bitmap_init_with_all_set(uint32_t n_bits, uint8_t *mem, uint32_t mem_size) { struct rte_bitmap *bmp; uint32_t array1_byte_offset, array1_slabs; uint32_t array2_byte_offset, array2_slabs; uint32_t size; /* Check input arguments */ if (!n_bits || !mem || (((uintptr_t) mem) & RTE_CACHE_LINE_MASK)) return NULL; size = __rte_bitmap_get_memory_footprint(n_bits, &array1_byte_offset, &array1_slabs, &array2_byte_offset, &array2_slabs); if (size < mem_size) return NULL; /* Setup bitmap */ bmp = (struct rte_bitmap *) mem; bmp->array1 = (uint64_t *) &mem[array1_byte_offset]; bmp->array1_size = array1_slabs; bmp->array2 = (uint64_t *) &mem[array2_byte_offset]; bmp->array2_size = array2_slabs; __rte_bitmap_scan_init(bmp); memset(bmp->array1, 0xff, bmp->array1_size * sizeof(bmp->array1[0])); memset(bmp->array2, 0xff, bmp->array2_size * sizeof(bmp->array2[0])); /* Clear overhead bits. */ __rte_bitmap_clear_slab_overhead_bits(bmp->array1, bmp->array1_size, bmp->array2_size >> RTE_BITMAP_CL_SLAB_SIZE_LOG2); __rte_bitmap_clear_slab_overhead_bits(bmp->array2, bmp->array2_size, n_bits); return bmp; } /** * Bitmap free * * This function does nothing in current implementation. * * @param bmp * Handle to bitmap instance */ static inline void rte_bitmap_free(struct rte_bitmap *bmp) { RTE_SET_USED(bmp); } /** * Bitmap reset * * @param bmp * Handle to bitmap instance */ static inline void rte_bitmap_reset(struct rte_bitmap *bmp) { memset(bmp->array1, 0, bmp->array1_size * sizeof(uint64_t)); memset(bmp->array2, 0, bmp->array2_size * sizeof(uint64_t)); __rte_bitmap_scan_init(bmp); } /** * Bitmap location prefetch into CPU L1 cache * * @param bmp * Handle to bitmap instance * @param pos * Bit position */ static inline void rte_bitmap_prefetch0(struct rte_bitmap *bmp, uint32_t pos) { uint64_t *slab2; uint32_t index2; index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; slab2 = bmp->array2 + index2; rte_prefetch0((void *) slab2); } /** * Bitmap bit get * * @param bmp * Handle to bitmap instance * @param pos * Bit position * @return * 0 when bit is cleared, non-zero when bit is set */ static inline uint64_t rte_bitmap_get(struct rte_bitmap *bmp, uint32_t pos) { uint64_t *slab2; uint32_t index2, offset2; index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK; slab2 = bmp->array2 + index2; return (*slab2) & (1llu << offset2); } /** * Bitmap bit set * * @param bmp * Handle to bitmap instance * @param pos * Bit position */ static inline void rte_bitmap_set(struct rte_bitmap *bmp, uint32_t pos) { uint64_t *slab1, *slab2; uint32_t index1, index2, offset1, offset2; /* Set bit in array2 slab and set bit in array1 slab */ index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK; index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2); offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK; slab2 = bmp->array2 + index2; slab1 = bmp->array1 + index1; *slab2 |= 1llu << offset2; *slab1 |= 1llu << offset1; } /** * Bitmap slab set * * @param bmp * Handle to bitmap instance * @param pos * Bit position identifying the array2 slab * @param slab * Value to be assigned to the 64-bit slab in array2 */ static inline void rte_bitmap_set_slab(struct rte_bitmap *bmp, uint32_t pos, uint64_t slab) { uint64_t *slab1, *slab2; uint32_t index1, index2, offset1; /* Set bits in array2 slab and set bit in array1 slab */ index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2); offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK; slab2 = bmp->array2 + index2; slab1 = bmp->array1 + index1; *slab2 |= slab; *slab1 |= 1llu << offset1; } #if RTE_BITMAP_CL_SLAB_SIZE == 8 static inline uint64_t __rte_bitmap_line_not_empty(uint64_t *slab2) { uint64_t v1, v2, v3, v4; v1 = slab2[0] | slab2[1]; v2 = slab2[2] | slab2[3]; v3 = slab2[4] | slab2[5]; v4 = slab2[6] | slab2[7]; v1 |= v2; v3 |= v4; return v1 | v3; } #elif RTE_BITMAP_CL_SLAB_SIZE == 16 static inline uint64_t __rte_bitmap_line_not_empty(uint64_t *slab2) { uint64_t v1, v2, v3, v4, v5, v6, v7, v8; v1 = slab2[0] | slab2[1]; v2 = slab2[2] | slab2[3]; v3 = slab2[4] | slab2[5]; v4 = slab2[6] | slab2[7]; v5 = slab2[8] | slab2[9]; v6 = slab2[10] | slab2[11]; v7 = slab2[12] | slab2[13]; v8 = slab2[14] | slab2[15]; v1 |= v2; v3 |= v4; v5 |= v6; v7 |= v8; return v1 | v3 | v5 | v7; } #endif /* RTE_BITMAP_CL_SLAB_SIZE */ /** * Bitmap bit clear * * @param bmp * Handle to bitmap instance * @param pos * Bit position */ static inline void rte_bitmap_clear(struct rte_bitmap *bmp, uint32_t pos) { uint64_t *slab1, *slab2; uint32_t index1, index2, offset1, offset2; /* Clear bit in array2 slab */ index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2; offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK; slab2 = bmp->array2 + index2; /* Return if array2 slab is not all-zeros */ *slab2 &= ~(1llu << offset2); if (*slab2){ return; } /* Check the entire cache line of array2 for all-zeros */ index2 &= ~ RTE_BITMAP_CL_SLAB_MASK; slab2 = bmp->array2 + index2; if (__rte_bitmap_line_not_empty(slab2)) { return; } /* The array2 cache line is all-zeros, so clear bit in array1 slab */ index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + RTE_BITMAP_CL_BIT_SIZE_LOG2); offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & RTE_BITMAP_SLAB_BIT_MASK; slab1 = bmp->array1 + index1; *slab1 &= ~(1llu << offset1); return; } static inline int __rte_bitmap_scan_search(struct rte_bitmap *bmp) { uint64_t value1; uint32_t i; /* Check current array1 slab */ value1 = bmp->array1[bmp->index1]; value1 &= __rte_bitmap_mask1_get(bmp); if (rte_bsf64_safe(value1, &bmp->offset1)) return 1; __rte_bitmap_index1_inc(bmp); bmp->offset1 = 0; /* Look for another array1 slab */ for (i = 0; i < bmp->array1_size; i ++, __rte_bitmap_index1_inc(bmp)) { value1 = bmp->array1[bmp->index1]; if (rte_bsf64_safe(value1, &bmp->offset1)) return 1; } return 0; } static inline void __rte_bitmap_scan_read_init(struct rte_bitmap *bmp) { __rte_bitmap_index2_set(bmp); bmp->go2 = 1; rte_prefetch1((void *)(bmp->array2 + bmp->index2 + 8)); } static inline int __rte_bitmap_scan_read(struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab) { uint64_t *slab2; slab2 = bmp->array2 + bmp->index2; for ( ; bmp->go2 ; bmp->index2 ++, slab2 ++, bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK) { if (*slab2) { *pos = bmp->index2 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2; *slab = *slab2; bmp->index2 ++; slab2 ++; bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK; return 1; } } return 0; } /** * Bitmap scan (with automatic wrap-around) * * @param bmp * Handle to bitmap instance * @param pos * When function call returns 1, pos contains the position of the next set * bit, otherwise not modified * @param slab * When function call returns 1, slab contains the value of the entire 64-bit * slab where the bit indicated by pos is located. Slabs are always 64-bit * aligned, so the position of the first bit of the slab (this bit is not * necessarily set) is pos / 64. Once a slab has been returned by the bitmap * scan operation, the internal pointers of the bitmap are updated to point * after this slab, so the same slab will not be returned again if it * contains more than one bit which is set. When function call returns 0, * slab is not modified. * @return * 0 if there is no bit set in the bitmap, 1 otherwise */ static inline int rte_bitmap_scan(struct rte_bitmap *bmp, uint32_t *pos, uint64_t *slab) { /* Return data from current array2 line if available */ if (__rte_bitmap_scan_read(bmp, pos, slab)) { return 1; } /* Look for non-empty array2 line */ if (__rte_bitmap_scan_search(bmp)) { __rte_bitmap_scan_read_init(bmp); __rte_bitmap_scan_read(bmp, pos, slab); return 1; } /* Empty bitmap */ return 0; } #ifdef __cplusplus } #endif #endif /* __INCLUDE_RTE_BITMAP_H__ */