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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-03-09 13:19:48 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-03-09 13:20:02 +0000 |
commit | 58daab21cd043e1dc37024a7f99b396788372918 (patch) | |
tree | 96771e43bb69f7c1c2b0b4f7374cb74d7866d0cb /fluent-bit/lib/jemalloc-5.3.0/src/ckh.c | |
parent | Releasing debian version 1.43.2-1. (diff) | |
download | netdata-58daab21cd043e1dc37024a7f99b396788372918.tar.xz netdata-58daab21cd043e1dc37024a7f99b396788372918.zip |
Merging upstream version 1.44.3.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fluent-bit/lib/jemalloc-5.3.0/src/ckh.c')
-rw-r--r-- | fluent-bit/lib/jemalloc-5.3.0/src/ckh.c | 569 |
1 files changed, 569 insertions, 0 deletions
diff --git a/fluent-bit/lib/jemalloc-5.3.0/src/ckh.c b/fluent-bit/lib/jemalloc-5.3.0/src/ckh.c new file mode 100644 index 000000000..8db4319c5 --- /dev/null +++ b/fluent-bit/lib/jemalloc-5.3.0/src/ckh.c @@ -0,0 +1,569 @@ +/* + ******************************************************************************* + * Implementation of (2^1+,2) cuckoo hashing, where 2^1+ indicates that each + * hash bucket contains 2^n cells, for n >= 1, and 2 indicates that two hash + * functions are employed. The original cuckoo hashing algorithm was described + * in: + * + * Pagh, R., F.F. Rodler (2004) Cuckoo Hashing. Journal of Algorithms + * 51(2):122-144. + * + * Generalization of cuckoo hashing was discussed in: + * + * Erlingsson, U., M. Manasse, F. McSherry (2006) A cool and practical + * alternative to traditional hash tables. In Proceedings of the 7th + * Workshop on Distributed Data and Structures (WDAS'06), Santa Clara, CA, + * January 2006. + * + * This implementation uses precisely two hash functions because that is the + * fewest that can work, and supporting multiple hashes is an implementation + * burden. Here is a reproduction of Figure 1 from Erlingsson et al. (2006) + * that shows approximate expected maximum load factors for various + * configurations: + * + * | #cells/bucket | + * #hashes | 1 | 2 | 4 | 8 | + * --------+-------+-------+-------+-------+ + * 1 | 0.006 | 0.006 | 0.03 | 0.12 | + * 2 | 0.49 | 0.86 |>0.93< |>0.96< | + * 3 | 0.91 | 0.97 | 0.98 | 0.999 | + * 4 | 0.97 | 0.99 | 0.999 | | + * + * The number of cells per bucket is chosen such that a bucket fits in one cache + * line. So, on 32- and 64-bit systems, we use (8,2) and (4,2) cuckoo hashing, + * respectively. + * + ******************************************************************************/ +#include "jemalloc/internal/jemalloc_preamble.h" + +#include "jemalloc/internal/ckh.h" + +#include "jemalloc/internal/jemalloc_internal_includes.h" + +#include "jemalloc/internal/assert.h" +#include "jemalloc/internal/hash.h" +#include "jemalloc/internal/malloc_io.h" +#include "jemalloc/internal/prng.h" +#include "jemalloc/internal/util.h" + +/******************************************************************************/ +/* Function prototypes for non-inline static functions. */ + +static bool ckh_grow(tsd_t *tsd, ckh_t *ckh); +static void ckh_shrink(tsd_t *tsd, ckh_t *ckh); + +/******************************************************************************/ + +/* + * Search bucket for key and return the cell number if found; SIZE_T_MAX + * otherwise. + */ +static size_t +ckh_bucket_search(ckh_t *ckh, size_t bucket, const void *key) { + ckhc_t *cell; + unsigned i; + + for (i = 0; i < (ZU(1) << LG_CKH_BUCKET_CELLS); i++) { + cell = &ckh->tab[(bucket << LG_CKH_BUCKET_CELLS) + i]; + if (cell->key != NULL && ckh->keycomp(key, cell->key)) { + return (bucket << LG_CKH_BUCKET_CELLS) + i; + } + } + + return SIZE_T_MAX; +} + +/* + * Search table for key and return cell number if found; SIZE_T_MAX otherwise. + */ +static size_t +ckh_isearch(ckh_t *ckh, const void *key) { + size_t hashes[2], bucket, cell; + + assert(ckh != NULL); + + ckh->hash(key, hashes); + + /* Search primary bucket. */ + bucket = hashes[0] & ((ZU(1) << ckh->lg_curbuckets) - 1); + cell = ckh_bucket_search(ckh, bucket, key); + if (cell != SIZE_T_MAX) { + return cell; + } + + /* Search secondary bucket. */ + bucket = hashes[1] & ((ZU(1) << ckh->lg_curbuckets) - 1); + cell = ckh_bucket_search(ckh, bucket, key); + return cell; +} + +static bool +ckh_try_bucket_insert(ckh_t *ckh, size_t bucket, const void *key, + const void *data) { + ckhc_t *cell; + unsigned offset, i; + + /* + * Cycle through the cells in the bucket, starting at a random position. + * The randomness avoids worst-case search overhead as buckets fill up. + */ + offset = (unsigned)prng_lg_range_u64(&ckh->prng_state, + LG_CKH_BUCKET_CELLS); + for (i = 0; i < (ZU(1) << LG_CKH_BUCKET_CELLS); i++) { + cell = &ckh->tab[(bucket << LG_CKH_BUCKET_CELLS) + + ((i + offset) & ((ZU(1) << LG_CKH_BUCKET_CELLS) - 1))]; + if (cell->key == NULL) { + cell->key = key; + cell->data = data; + ckh->count++; + return false; + } + } + + return true; +} + +/* + * No space is available in bucket. Randomly evict an item, then try to find an + * alternate location for that item. Iteratively repeat this + * eviction/relocation procedure until either success or detection of an + * eviction/relocation bucket cycle. + */ +static bool +ckh_evict_reloc_insert(ckh_t *ckh, size_t argbucket, void const **argkey, + void const **argdata) { + const void *key, *data, *tkey, *tdata; + ckhc_t *cell; + size_t hashes[2], bucket, tbucket; + unsigned i; + + bucket = argbucket; + key = *argkey; + data = *argdata; + while (true) { + /* + * Choose a random item within the bucket to evict. This is + * critical to correct function, because without (eventually) + * evicting all items within a bucket during iteration, it + * would be possible to get stuck in an infinite loop if there + * were an item for which both hashes indicated the same + * bucket. + */ + i = (unsigned)prng_lg_range_u64(&ckh->prng_state, + LG_CKH_BUCKET_CELLS); + cell = &ckh->tab[(bucket << LG_CKH_BUCKET_CELLS) + i]; + assert(cell->key != NULL); + + /* Swap cell->{key,data} and {key,data} (evict). */ + tkey = cell->key; tdata = cell->data; + cell->key = key; cell->data = data; + key = tkey; data = tdata; + +#ifdef CKH_COUNT + ckh->nrelocs++; +#endif + + /* Find the alternate bucket for the evicted item. */ + ckh->hash(key, hashes); + tbucket = hashes[1] & ((ZU(1) << ckh->lg_curbuckets) - 1); + if (tbucket == bucket) { + tbucket = hashes[0] & ((ZU(1) << ckh->lg_curbuckets) + - 1); + /* + * It may be that (tbucket == bucket) still, if the + * item's hashes both indicate this bucket. However, + * we are guaranteed to eventually escape this bucket + * during iteration, assuming pseudo-random item + * selection (true randomness would make infinite + * looping a remote possibility). The reason we can + * never get trapped forever is that there are two + * cases: + * + * 1) This bucket == argbucket, so we will quickly + * detect an eviction cycle and terminate. + * 2) An item was evicted to this bucket from another, + * which means that at least one item in this bucket + * has hashes that indicate distinct buckets. + */ + } + /* Check for a cycle. */ + if (tbucket == argbucket) { + *argkey = key; + *argdata = data; + return true; + } + + bucket = tbucket; + if (!ckh_try_bucket_insert(ckh, bucket, key, data)) { + return false; + } + } +} + +static bool +ckh_try_insert(ckh_t *ckh, void const**argkey, void const**argdata) { + size_t hashes[2], bucket; + const void *key = *argkey; + const void *data = *argdata; + + ckh->hash(key, hashes); + + /* Try to insert in primary bucket. */ + bucket = hashes[0] & ((ZU(1) << ckh->lg_curbuckets) - 1); + if (!ckh_try_bucket_insert(ckh, bucket, key, data)) { + return false; + } + + /* Try to insert in secondary bucket. */ + bucket = hashes[1] & ((ZU(1) << ckh->lg_curbuckets) - 1); + if (!ckh_try_bucket_insert(ckh, bucket, key, data)) { + return false; + } + + /* + * Try to find a place for this item via iterative eviction/relocation. + */ + return ckh_evict_reloc_insert(ckh, bucket, argkey, argdata); +} + +/* + * Try to rebuild the hash table from scratch by inserting all items from the + * old table into the new. + */ +static bool +ckh_rebuild(ckh_t *ckh, ckhc_t *aTab) { + size_t count, i, nins; + const void *key, *data; + + count = ckh->count; + ckh->count = 0; + for (i = nins = 0; nins < count; i++) { + if (aTab[i].key != NULL) { + key = aTab[i].key; + data = aTab[i].data; + if (ckh_try_insert(ckh, &key, &data)) { + ckh->count = count; + return true; + } + nins++; + } + } + + return false; +} + +static bool +ckh_grow(tsd_t *tsd, ckh_t *ckh) { + bool ret; + ckhc_t *tab, *ttab; + unsigned lg_prevbuckets, lg_curcells; + +#ifdef CKH_COUNT + ckh->ngrows++; +#endif + + /* + * It is possible (though unlikely, given well behaved hashes) that the + * table will have to be doubled more than once in order to create a + * usable table. + */ + lg_prevbuckets = ckh->lg_curbuckets; + lg_curcells = ckh->lg_curbuckets + LG_CKH_BUCKET_CELLS; + while (true) { + size_t usize; + + lg_curcells++; + usize = sz_sa2u(sizeof(ckhc_t) << lg_curcells, CACHELINE); + if (unlikely(usize == 0 + || usize > SC_LARGE_MAXCLASS)) { + ret = true; + goto label_return; + } + tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE, + true, NULL, true, arena_ichoose(tsd, NULL)); + if (tab == NULL) { + ret = true; + goto label_return; + } + /* Swap in new table. */ + ttab = ckh->tab; + ckh->tab = tab; + tab = ttab; + ckh->lg_curbuckets = lg_curcells - LG_CKH_BUCKET_CELLS; + + if (!ckh_rebuild(ckh, tab)) { + idalloctm(tsd_tsdn(tsd), tab, NULL, NULL, true, true); + break; + } + + /* Rebuilding failed, so back out partially rebuilt table. */ + idalloctm(tsd_tsdn(tsd), ckh->tab, NULL, NULL, true, true); + ckh->tab = tab; + ckh->lg_curbuckets = lg_prevbuckets; + } + + ret = false; +label_return: + return ret; +} + +static void +ckh_shrink(tsd_t *tsd, ckh_t *ckh) { + ckhc_t *tab, *ttab; + size_t usize; + unsigned lg_prevbuckets, lg_curcells; + + /* + * It is possible (though unlikely, given well behaved hashes) that the + * table rebuild will fail. + */ + lg_prevbuckets = ckh->lg_curbuckets; + lg_curcells = ckh->lg_curbuckets + LG_CKH_BUCKET_CELLS - 1; + usize = sz_sa2u(sizeof(ckhc_t) << lg_curcells, CACHELINE); + if (unlikely(usize == 0 || usize > SC_LARGE_MAXCLASS)) { + return; + } + tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE, true, NULL, + true, arena_ichoose(tsd, NULL)); + if (tab == NULL) { + /* + * An OOM error isn't worth propagating, since it doesn't + * prevent this or future operations from proceeding. + */ + return; + } + /* Swap in new table. */ + ttab = ckh->tab; + ckh->tab = tab; + tab = ttab; + ckh->lg_curbuckets = lg_curcells - LG_CKH_BUCKET_CELLS; + + if (!ckh_rebuild(ckh, tab)) { + idalloctm(tsd_tsdn(tsd), tab, NULL, NULL, true, true); +#ifdef CKH_COUNT + ckh->nshrinks++; +#endif + return; + } + + /* Rebuilding failed, so back out partially rebuilt table. */ + idalloctm(tsd_tsdn(tsd), ckh->tab, NULL, NULL, true, true); + ckh->tab = tab; + ckh->lg_curbuckets = lg_prevbuckets; +#ifdef CKH_COUNT + ckh->nshrinkfails++; +#endif +} + +bool +ckh_new(tsd_t *tsd, ckh_t *ckh, size_t minitems, ckh_hash_t *ckh_hash, + ckh_keycomp_t *keycomp) { + bool ret; + size_t mincells, usize; + unsigned lg_mincells; + + assert(minitems > 0); + assert(ckh_hash != NULL); + assert(keycomp != NULL); + +#ifdef CKH_COUNT + ckh->ngrows = 0; + ckh->nshrinks = 0; + ckh->nshrinkfails = 0; + ckh->ninserts = 0; + ckh->nrelocs = 0; +#endif + ckh->prng_state = 42; /* Value doesn't really matter. */ + ckh->count = 0; + + /* + * Find the minimum power of 2 that is large enough to fit minitems + * entries. We are using (2+,2) cuckoo hashing, which has an expected + * maximum load factor of at least ~0.86, so 0.75 is a conservative load + * factor that will typically allow mincells items to fit without ever + * growing the table. + */ + assert(LG_CKH_BUCKET_CELLS > 0); + mincells = ((minitems + (3 - (minitems % 3))) / 3) << 2; + for (lg_mincells = LG_CKH_BUCKET_CELLS; + (ZU(1) << lg_mincells) < mincells; + lg_mincells++) { + /* Do nothing. */ + } + ckh->lg_minbuckets = lg_mincells - LG_CKH_BUCKET_CELLS; + ckh->lg_curbuckets = lg_mincells - LG_CKH_BUCKET_CELLS; + ckh->hash = ckh_hash; + ckh->keycomp = keycomp; + + usize = sz_sa2u(sizeof(ckhc_t) << lg_mincells, CACHELINE); + if (unlikely(usize == 0 || usize > SC_LARGE_MAXCLASS)) { + ret = true; + goto label_return; + } + ckh->tab = (ckhc_t *)ipallocztm(tsd_tsdn(tsd), usize, CACHELINE, true, + NULL, true, arena_ichoose(tsd, NULL)); + if (ckh->tab == NULL) { + ret = true; + goto label_return; + } + + ret = false; +label_return: + return ret; +} + +void +ckh_delete(tsd_t *tsd, ckh_t *ckh) { + assert(ckh != NULL); + +#ifdef CKH_VERBOSE + malloc_printf( + "%s(%p): ngrows: %"FMTu64", nshrinks: %"FMTu64"," + " nshrinkfails: %"FMTu64", ninserts: %"FMTu64"," + " nrelocs: %"FMTu64"\n", __func__, ckh, + (unsigned long long)ckh->ngrows, + (unsigned long long)ckh->nshrinks, + (unsigned long long)ckh->nshrinkfails, + (unsigned long long)ckh->ninserts, + (unsigned long long)ckh->nrelocs); +#endif + + idalloctm(tsd_tsdn(tsd), ckh->tab, NULL, NULL, true, true); + if (config_debug) { + memset(ckh, JEMALLOC_FREE_JUNK, sizeof(ckh_t)); + } +} + +size_t +ckh_count(ckh_t *ckh) { + assert(ckh != NULL); + + return ckh->count; +} + +bool +ckh_iter(ckh_t *ckh, size_t *tabind, void **key, void **data) { + size_t i, ncells; + + for (i = *tabind, ncells = (ZU(1) << (ckh->lg_curbuckets + + LG_CKH_BUCKET_CELLS)); i < ncells; i++) { + if (ckh->tab[i].key != NULL) { + if (key != NULL) { + *key = (void *)ckh->tab[i].key; + } + if (data != NULL) { + *data = (void *)ckh->tab[i].data; + } + *tabind = i + 1; + return false; + } + } + + return true; +} + +bool +ckh_insert(tsd_t *tsd, ckh_t *ckh, const void *key, const void *data) { + bool ret; + + assert(ckh != NULL); + assert(ckh_search(ckh, key, NULL, NULL)); + +#ifdef CKH_COUNT + ckh->ninserts++; +#endif + + while (ckh_try_insert(ckh, &key, &data)) { + if (ckh_grow(tsd, ckh)) { + ret = true; + goto label_return; + } + } + + ret = false; +label_return: + return ret; +} + +bool +ckh_remove(tsd_t *tsd, ckh_t *ckh, const void *searchkey, void **key, + void **data) { + size_t cell; + + assert(ckh != NULL); + + cell = ckh_isearch(ckh, searchkey); + if (cell != SIZE_T_MAX) { + if (key != NULL) { + *key = (void *)ckh->tab[cell].key; + } + if (data != NULL) { + *data = (void *)ckh->tab[cell].data; + } + ckh->tab[cell].key = NULL; + ckh->tab[cell].data = NULL; /* Not necessary. */ + + ckh->count--; + /* Try to halve the table if it is less than 1/4 full. */ + if (ckh->count < (ZU(1) << (ckh->lg_curbuckets + + LG_CKH_BUCKET_CELLS - 2)) && ckh->lg_curbuckets + > ckh->lg_minbuckets) { + /* Ignore error due to OOM. */ + ckh_shrink(tsd, ckh); + } + + return false; + } + + return true; +} + +bool +ckh_search(ckh_t *ckh, const void *searchkey, void **key, void **data) { + size_t cell; + + assert(ckh != NULL); + + cell = ckh_isearch(ckh, searchkey); + if (cell != SIZE_T_MAX) { + if (key != NULL) { + *key = (void *)ckh->tab[cell].key; + } + if (data != NULL) { + *data = (void *)ckh->tab[cell].data; + } + return false; + } + + return true; +} + +void +ckh_string_hash(const void *key, size_t r_hash[2]) { + hash(key, strlen((const char *)key), 0x94122f33U, r_hash); +} + +bool +ckh_string_keycomp(const void *k1, const void *k2) { + assert(k1 != NULL); + assert(k2 != NULL); + + return !strcmp((char *)k1, (char *)k2); +} + +void +ckh_pointer_hash(const void *key, size_t r_hash[2]) { + union { + const void *v; + size_t i; + } u; + + assert(sizeof(u.v) == sizeof(u.i)); + u.v = key; + hash(&u.i, sizeof(u.i), 0xd983396eU, r_hash); +} + +bool +ckh_pointer_keycomp(const void *k1, const void *k2) { + return (k1 == k2); +} |