* weaker operations which would still do the job.
*/
+#include <stdio.h>
#include "common.h"
#include "murmur.h"
#include "mem.h"
-#include "mlocal.h"
-#include "nstring.h"
+#include "hashtable.h"
-#define GET_PTR(x) ((nstring_t *)((x) & MASK(48))) // low-order 48 bits is a pointer to a nstring_t
+#define GET_PTR(x) ((void *)((x) & MASK(48))) // low-order 48 bits is a pointer to a nstring_t
typedef struct ht_entry {
- uint64_t key; // ptr to nstring_t
- uint64_t value;
+ uint64_t key;
+ uint64_t val;
} entry_t;
typedef struct hti {
volatile entry_t *table;
hashtable_t *ht; // parent ht;
struct hti *next;
- struct hti *next_free;
unsigned int scale;
int max_probe;
int count; // TODO: make these counters distributed
int num_entries_copied;
int scan;
-} hashtable_i_t;
+} hti_t;
struct ht {
- hashtable_i_t *hti;
-};
-
-static const map_impl_t ht_map_impl = {
- (map_alloc_t)ht_alloc, (map_cas_t)ht_cas, (map_get_t)ht_get, (map_remove_t)ht_remove,
- (map_count_t)ht_count, (map_print_t)ht_print, (map_free_t)ht_free
+ hti_t *hti;
+ const datatype_t *key_type;
};
-const map_impl_t *MAP_TYPE_HASHTABLE = &ht_map_impl;
-
static const uint64_t COPIED_VALUE = -1;
-static const uint64_t TOMBSTONE = STRIP_TAG(-1);
+static const uint64_t TOMBSTONE = STRIP_TAG(-1, TAG1);
static const unsigned ENTRIES_PER_BUCKET = CACHE_LINE_SIZE/sizeof(entry_t);
static const unsigned ENTRIES_PER_COPY_CHUNK = CACHE_LINE_SIZE/sizeof(entry_t)*2;
static const unsigned MIN_SCALE = 4; // min 16 entries (4 buckets)
static const unsigned MAX_BUCKETS_TO_PROBE = 250;
-static int hti_copy_entry (hashtable_i_t *ht1, volatile entry_t *e, uint32_t e_key_hash, hashtable_i_t *ht2);
+static int hti_copy_entry (hti_t *ht1, volatile entry_t *ent, uint32_t ent_key_hash, hti_t *ht2);
// Choose the next bucket to probe using the high-order bits of <key_hash>.
static inline int get_next_ndx(int old_ndx, uint32_t key_hash, int ht_scale) {
return (old_ndx + incr) & MASK(ht_scale);
}
-// Compare two keys.
-//
-// A key is made up of two parts. The 48 low-order bits are a pointer to a null terminated string.
-// The high-order 16 bits are taken from the hash of that string. The bits from the hash are used
-// as a quick check to rule out non-equal keys without doing a complete string compare.
-static inline int ht_key_equals (uint64_t a, uint32_t b_hash, const char *b_value, uint32_t b_len) {
- if ((b_hash >> 16) != (a >> 48)) // high-order 16 bits are from the hash value
- return FALSE;
- return ns_cmp_raw(GET_PTR(a), b_value, b_len) == 0;
-}
-
// Lookup <key> in <hti>.
//
// Return the entry that <key> is in, or if <key> isn't in <hti> return the entry that it would be
// in if it were inserted into <hti>. If there is no room for <key> in <hti> then return NULL, to
// indicate that the caller should look in <hti->next>.
//
-// Record if the entry being returned is empty. Otherwise the caller will have to waste time with
-// ht_key_equals() to confirm that it did not lose a race to fill an empty entry.
-static volatile entry_t *hti_lookup (hashtable_i_t *hti, uint32_t key_hash, const char *key_data, uint32_t key_len, int *is_empty) {
- TRACE("h2", "hti_lookup(key %p in hti %p)", key_data, hti);
+// Record if the entry being returned is empty. Otherwise the caller will have to waste time
+// re-comparing the keys to confirm that it did not lose a race to fill an empty entry.
+static volatile entry_t *hti_lookup (hti_t *hti, void *key, uint32_t key_hash, int *is_empty) {
+ TRACE("h2", "hti_lookup(key %p in hti %p)", key, hti);
*is_empty = 0;
// Probe one cache line at a time
// Start searching at the indexed entry. Then loop around to the begining of the cache line.
for (int j = 0; j < ENTRIES_PER_BUCKET; ++j) {
- volatile entry_t *e = bucket + ((ndx + j) & (ENTRIES_PER_BUCKET-1));
-
- uint64_t e_key = e->key;
- if (e_key == DOES_NOT_EXIST) {
- TRACE("h1", "hti_lookup: entry %p for key \"%s\" is empty", e, GET_PTR(e_key)->data);
- *is_empty = 1; // indicate an empty so the caller avoids an expensive ht_key_equals
- return e;
+ volatile entry_t *ent = bucket + ((ndx + j) & (ENTRIES_PER_BUCKET-1));
+
+ uint64_t ent_key = ent->key;
+ if (ent_key == DOES_NOT_EXIST) {
+ TRACE("h1", "hti_lookup: entry %p for key %p is empty", ent,
+ (hti->ht->key_type == NULL) ? (void *)ent_key : GET_PTR(ent_key));
+ *is_empty = 1; // indicate an empty so the caller avoids an expensive key compare
+ return ent;
}
- if (ht_key_equals(e_key, key_hash, key_data, key_len)) {
- TRACE("h1", "hti_lookup: entry %p key \"%s\"", e, GET_PTR(e_key)->data);
- TRACE("h2", "hti_lookup: entry key len %llu, value %p", GET_PTR(e_key)->len, e->value);
- return e;
+ // Compare <key> with the key in the entry.
+ if (EXPECT_TRUE(hti->ht->key_type == NULL)) {
+ // fast path for integer keys
+ if (ent_key == (uint64_t)key) {
+ TRACE("h1", "hti_lookup: found entry %p with key %p", ent, ent_key);
+ return ent;
+ }
+ } else {
+ // The key in <ent> is made up of two parts. The 48 low-order bits are a pointer. The
+ // high-order 16 bits are taken from the hash. The bits from the hash are used as a
+ // quick check to rule out non-equal keys without doing a complete compare.
+ if ((key_hash >> 16) == (ent_key >> 48) && hti->ht->key_type->cmp(GET_PTR(ent_key), key) == 0) {
+ TRACE("h1", "hti_lookup: found entry %p with key %p", ent, GET_PTR(ent_key));
+ return ent;
+ }
}
}
return NULL;
}
-// Allocate and initialize a hashtable_i_t with 2^<scale> entries.
-static hashtable_i_t *hti_alloc (hashtable_t *parent, int scale) {
+// Allocate and initialize a hti_t with 2^<scale> entries.
+static hti_t *hti_alloc (hashtable_t *parent, int scale) {
// Include enough slop to align the actual table on a cache line boundry
- size_t n = sizeof(hashtable_i_t)
+ size_t n = sizeof(hti_t)
+ sizeof(entry_t) * (1 << scale)
+ (CACHE_LINE_SIZE - 1);
- hashtable_i_t *hti = (hashtable_i_t *)calloc(n, 1);
+ hti_t *hti = (hti_t *)calloc(n, 1);
// Align the table of hash entries on a cache line boundry.
- hti->table = (entry_t *)(((uint64_t)hti + sizeof(hashtable_i_t) + (CACHE_LINE_SIZE-1))
+ hti->table = (entry_t *)(((uint64_t)hti + sizeof(hti_t) + (CACHE_LINE_SIZE-1))
& ~(CACHE_LINE_SIZE-1));
hti->scale = scale;
// When searching for a key probe a maximum of 1/4 of the buckets up to 1000 buckets.
- hti->max_probe = ((1 << (hti->scale - 2)) / ENTRIES_PER_BUCKET) + 2;
+ hti->max_probe = ((1 << (hti->scale - 2)) / ENTRIES_PER_BUCKET) + 4;
if (hti->max_probe > MAX_BUCKETS_TO_PROBE) {
hti->max_probe = MAX_BUCKETS_TO_PROBE;
}
// Called when <hti> runs out of room for new keys.
//
-// Initiates a copy by creating a larger hashtable_i_t and installing it in <hti->next>.
-static void hti_start_copy (hashtable_i_t *hti) {
+// Initiates a copy by creating a larger hti_t and installing it in <hti->next>.
+static void hti_start_copy (hti_t *hti) {
TRACE("h0", "hti_start_copy(hti %p scale %llu)", hti, hti->scale);
// heuristics to determine the size of the new table
new_scale += (count > (1 << (new_scale - 2))); // double size again if more than 1/2 full
// Allocate the new table and attempt to install it.
- hashtable_i_t *next = hti_alloc(hti->ht, new_scale);
- hashtable_i_t *old_next = SYNC_CAS(&hti->next, NULL, next);
+ hti_t *next = hti_alloc(hti->ht, new_scale);
+ hti_t *old_next = SYNC_CAS(&hti->next, NULL, next);
if (old_next != NULL) {
// Another thread beat us to it.
TRACE("h0", "hti_start_copy: lost race to install new hti; found %p", old_next, 0);
TRACE("h0", "hti_start_copy: new hti %p scale %llu", next, next->scale);
}
-// Copy the key and value stored in <ht1_e> (which must be an entry in <ht1>) to <ht2>.
+// Copy the key and value stored in <ht1_ent> (which must be an entry in <ht1>) to <ht2>.
//
-// Return 1 unless <ht1_e> is already copied (then return 0), so the caller can account for the total
+// Return 1 unless <ht1_ent> is already copied (then return 0), so the caller can account for the total
// number of entries left to copy.
-static int hti_copy_entry (hashtable_i_t *ht1, volatile entry_t *ht1_e, uint32_t key_hash,
- hashtable_i_t *ht2) {
- TRACE("h2", "hti_copy_entry: entry %p to table %p", ht1_e, ht2);
+static int hti_copy_entry (hti_t *ht1, volatile entry_t *ht1_ent, uint32_t key_hash, hti_t *ht2) {
+ TRACE("h2", "hti_copy_entry: entry %p to table %p", ht1_ent, ht2);
assert(ht1);
assert(ht1->next);
assert(ht2);
- assert(ht1_e >= ht1->table && ht1_e < ht1->table + (1 << ht1->scale));
- assert(key_hash == 0 || (key_hash >> 16) == (ht1_e->key >> 48));
+ assert(ht1_ent >= ht1->table && ht1_ent < ht1->table + (1 << ht1->scale));
+ assert(key_hash == 0 || ht1->ht->key_type == NULL || (key_hash >> 16) == (ht1_ent->key >> 48));
- uint64_t ht1_e_value = ht1_e->value;
- if (EXPECT_FALSE(ht1_e_value == COPIED_VALUE)) {
- TRACE("h1", "hti_copy_entry: entry %p already copied to table %p", ht1_e, ht2);
+ uint64_t ht1_ent_val = ht1_ent->val;
+ if (EXPECT_FALSE(ht1_ent_val == COPIED_VALUE)) {
+ TRACE("h1", "hti_copy_entry: entry %p already copied to table %p", ht1_ent, ht2);
return FALSE; // already copied
}
// Kill empty entries.
- if (EXPECT_FALSE(ht1_e_value == DOES_NOT_EXIST)) {
- uint64_t ht1_e_value = SYNC_CAS(&ht1_e->value, DOES_NOT_EXIST, COPIED_VALUE);
- if (ht1_e_value == DOES_NOT_EXIST) {
- TRACE("h1", "hti_copy_entry: empty entry %p killed", ht1_e, 0);
+ if (EXPECT_FALSE(ht1_ent_val == DOES_NOT_EXIST)) {
+ uint64_t ht1_ent_val = SYNC_CAS(&ht1_ent->val, DOES_NOT_EXIST, COPIED_VALUE);
+ if (ht1_ent_val == DOES_NOT_EXIST) {
+ TRACE("h1", "hti_copy_entry: empty entry %p killed", ht1_ent, 0);
return TRUE;
}
- if (ht1_e_value == COPIED_VALUE) {
- TRACE("h0", "hti_copy_entry: lost race to kill empty entry %p", ht1_e, 0);
+ if (ht1_ent_val == COPIED_VALUE) {
+ TRACE("h0", "hti_copy_entry: lost race to kill empty entry %p; the entry is already killed", ht1_ent, 0);
return FALSE; // another thread beat us to it
}
- TRACE("h0", "hti_copy_entry: lost race to kill empty entry %p; the entry is now"
- "in use and should be copied", ht1_e, 0);
+ TRACE("h0", "hti_copy_entry: lost race to kill empty entry %p; the entry is not empty", ht1_ent, 0);
}
// Tag the value in the old entry to indicate a copy is in progress.
- ht1_e_value = SYNC_FETCH_AND_OR(&ht1_e->value, TAG_VALUE(0));
- TRACE("h2", "hti_copy_entry: tagged the value %p in old entry %p", ht1_e_value, ht1_e);
- if (ht1_e_value == COPIED_VALUE) {
- TRACE("h1", "hti_copy_entry: entry %p already copied to table %p", ht1_e, ht2);
+ ht1_ent_val = SYNC_FETCH_AND_OR(&ht1_ent->val, TAG_VALUE(0, TAG1));
+ TRACE("h2", "hti_copy_entry: tagged the value %p in old entry %p", ht1_ent_val, ht1_ent);
+ if (ht1_ent_val == COPIED_VALUE) {
+ TRACE("h1", "hti_copy_entry: entry %p already copied to table %p", ht1_ent, ht2);
return FALSE; // <value> was already copied by another thread.
}
- // The old table's deleted entries don't need to be copied to the new table, but their keys need
- // to be freed.
- assert(COPIED_VALUE == TAG_VALUE(TOMBSTONE));
- if (ht1_e_value == TOMBSTONE) {
- TRACE("h1", "hti_copy_entry: entry %p old value was deleted, now freeing key %p", ht1_e, GET_PTR(ht1_e->key));
- nbd_defer_free(GET_PTR(ht1_e->key));
+ // Install the key in the new table.
+ uint64_t ht1_ent_key = ht1_ent->key;
+ void *key = (ht1->ht->key_type == NULL) ? (void *)ht1_ent_key : GET_PTR(ht1_ent_key);
+
+ // The old table's dead entries don't need to be copied to the new table, but their keys need to be freed.
+ assert(COPIED_VALUE == TAG_VALUE(TOMBSTONE, TAG1));
+ if (ht1_ent_val == TOMBSTONE) {
+ TRACE("h1", "hti_copy_entry: entry %p old value was deleted, now freeing key %p", ht1_ent, key);
+ if (EXPECT_FALSE(ht1->ht->key_type != NULL)) {
+ nbd_defer_free(key);
+ }
return TRUE;
}
- // Install the key in the new table.
- uint64_t key = ht1_e->key;
- nstring_t *key_string = GET_PTR(key);
- uint64_t value = STRIP_TAG(ht1_e_value);
-
- // We use 0 to indicate that <key_hash> isn't initiallized. Occasionally the <key_hash> will
- // really be 0 and we will waste time recomputing it. That is rare enough that it is OK.
+ // We use 0 to indicate that <key_hash> is uninitiallized. Occasionally the key's hash will really be 0 and we
+ // waste time recomputing it every time. It is rare enough (1 in 65k) that it won't hurt performance.
if (key_hash == 0) {
- key_hash = murmur32(key_string->data, key_string->len);
+ key_hash = (ht1->ht->key_type == NULL) ? murmur32_8b(ht1_ent_key) : ht1->ht->key_type->hash(key);
}
- int is_empty;
- volatile entry_t *ht2_e = hti_lookup(ht2, key_hash, key_string->data, key_string->len, &is_empty);
- TRACE("h0", "hti_copy_entry: copy entry %p to entry %p", ht1_e, ht2_e);
+ int ht2_ent_is_empty;
+ volatile entry_t *ht2_ent = hti_lookup(ht2, key, key_hash, &ht2_ent_is_empty);
+ TRACE("h0", "hti_copy_entry: copy entry %p to entry %p", ht1_ent, ht2_ent);
- // it is possible that there is not any room in the new table either
- if (EXPECT_FALSE(ht2_e == NULL)) {
+ // It is possible that there isn't any room in the new table either.
+ if (EXPECT_FALSE(ht2_ent == NULL)) {
TRACE("h0", "hti_copy_entry: no room in table %p copy to next table %p", ht2, ht2->next);
if (ht2->next == NULL) {
hti_start_copy(ht2); // initiate nested copy, if not already started
}
- return hti_copy_entry(ht1, ht1_e, key_hash, ht2->next); // recursive tail-call
+ return hti_copy_entry(ht1, ht1_ent, key_hash, ht2->next); // recursive tail-call
}
- // a tagged entry returned from hti_lookup() means it is either empty or has a new key
- if (is_empty) {
- uint64_t old_ht2_e_key = SYNC_CAS(&ht2_e->key, DOES_NOT_EXIST, key);
- if (old_ht2_e_key != DOES_NOT_EXIST) {
+ if (ht2_ent_is_empty) {
+ uint64_t old_ht2_ent_key = SYNC_CAS(&ht2_ent->key, DOES_NOT_EXIST, ht1_ent_key);
+ if (old_ht2_ent_key != DOES_NOT_EXIST) {
TRACE("h0", "hti_copy_entry: lost race to CAS key %p into new entry; found %p",
- key, old_ht2_e_key);
- return hti_copy_entry(ht1, ht1_e, key_hash, ht2); // recursive tail-call
+ ht1_ent_key, old_ht2_ent_key);
+ return hti_copy_entry(ht1, ht1_ent, key_hash, ht2); // recursive tail-call
}
}
// Copy the value to the entry in the new table.
- uint64_t old_ht2_e_value = SYNC_CAS(&ht2_e->value, DOES_NOT_EXIST, value);
+ ht1_ent_val = STRIP_TAG(ht1_ent_val, TAG1);
+ uint64_t old_ht2_ent_val = SYNC_CAS(&ht2_ent->val, DOES_NOT_EXIST, ht1_ent_val);
// If there is a nested copy in progress, we might have installed the key into a dead entry.
- if (old_ht2_e_value == COPIED_VALUE) {
- TRACE("h0", "hti_copy_entry: nested copy in progress; copy %p to next table %p", ht2_e, ht2->next);
- return hti_copy_entry(ht1, ht1_e, key_hash, ht2->next); // recursive tail-call
+ if (old_ht2_ent_val == COPIED_VALUE) {
+ TRACE("h0", "hti_copy_entry: nested copy in progress; copy %p to next table %p", ht2_ent, ht2->next);
+ return hti_copy_entry(ht1, ht1_ent, key_hash, ht2->next); // recursive tail-call
}
// Mark the old entry as dead.
- ht1_e->value = COPIED_VALUE;
+ ht1_ent->val = COPIED_VALUE;
// Update the count if we were the one that completed the copy.
- if (old_ht2_e_value == DOES_NOT_EXIST) {
- TRACE("h0", "hti_copy_entry: key \"%s\" value %p copied to new entry", key_string->data, value);
+ if (old_ht2_ent_val == DOES_NOT_EXIST) {
+ TRACE("h0", "hti_copy_entry: key %p value %p copied to new entry", key, ht1_ent_val);
SYNC_ADD(&ht1->count, -1);
SYNC_ADD(&ht2->count, 1);
return TRUE;
}
TRACE("h0", "hti_copy_entry: lost race to install value %p in new entry; found value %p",
- value, old_ht2_e_value);
+ ht1_ent_val, old_ht2_ent_val);
return FALSE; // another thread completed the copy
}
// Compare <expected> with the existing value associated with <key>. If the values match then
-// replace the existing value with <new>. If <new> is TOMBSTONE, delete the value associated with
+// replace the existing value with <new>. If <new> is DOES_NOT_EXIST, delete the value associated with
// the key by replacing it with a TOMBSTONE.
//
// Return the previous value associated with <key>, or DOES_NOT_EXIST if <key> is not in the table
// NOTE: the returned value matches <expected> iff the set succeeds
//
// Certain values of <expected> have special meaning. If <expected> is CAS_EXPECT_EXISTS then any
-// real value matches (i.e. not a TOMBSTONE or DOES_NOT_EXIST) as long as <key> is in the table. If
+// real value matches (i.ent. not a TOMBSTONE or DOES_NOT_EXIST) as long as <key> is in the table. If
// <expected> is CAS_EXPECT_WHATEVER then skip the test entirely.
//
-static uint64_t hti_cas (hashtable_i_t *hti, uint32_t key_hash, const char *key_data, uint32_t key_len,
- uint64_t expected, uint64_t new) {
- TRACE("h1", "hti_cas: hti %p key %p", hti, key_data);
+static uint64_t hti_cas (hti_t *hti, void *key, uint32_t key_hash, uint64_t expected, uint64_t new) {
+ TRACE("h1", "hti_cas: hti %p key %p", hti, key);
TRACE("h1", "hti_cas: value %p expect %p", new, expected);
assert(hti);
- assert(new != DOES_NOT_EXIST && !IS_TAGGED(new));
- assert(key_data);
+ assert(!IS_TAGGED(new, TAG1));
+ assert(key);
int is_empty;
- volatile entry_t *e = hti_lookup(hti, key_hash, key_data, key_len, &is_empty);
+ volatile entry_t *ent = hti_lookup(hti, key, key_hash, &is_empty);
// There is no room for <key>, grow the table and try again.
- if (e == NULL) {
+ if (ent == NULL) {
if (hti->next == NULL) {
hti_start_copy(hti);
}
// Install <key> in the table if it doesn't exist.
if (is_empty) {
- TRACE("h0", "hti_cas: entry %p is empty", e, 0);
+ TRACE("h0", "hti_cas: entry %p is empty", ent, 0);
if (expected != CAS_EXPECT_WHATEVER && expected != CAS_EXPECT_DOES_NOT_EXIST)
return DOES_NOT_EXIST;
// No need to do anything, <key> is already deleted.
- if (new == TOMBSTONE)
+ if (new == DOES_NOT_EXIST)
return DOES_NOT_EXIST;
- // Allocate <key>.
- nstring_t *key = ns_alloc(key_data, key_len);
+ // Allocate <new_key>.
+ uint64_t new_key = (uint64_t)((hti->ht->key_type == NULL) ? key : hti->ht->key_type->clone(key));
+ if (EXPECT_FALSE(hti->ht->key_type != NULL)) {
+ // Combine <new_key> pointer with bits from its hash
+ new_key = ((uint64_t)(key_hash >> 16) << 48) | new_key;
+ }
- // Combine <key> pointer with bits from its hash, CAS it into the table.
- uint64_t temp = ((uint64_t)(key_hash >> 16) << 48) | (uint64_t)key;
- uint64_t e_key = SYNC_CAS(&e->key, DOES_NOT_EXIST, temp);
+ // CAS the key into the table.
+ uint64_t old_ent_key = SYNC_CAS(&ent->key, DOES_NOT_EXIST, new_key);
// Retry if another thread stole the entry out from under us.
- if (e_key != DOES_NOT_EXIST) {
- TRACE("h0", "hti_cas: lost race to install key %p in entry %p", key, e);
- TRACE("h0", "hti_cas: found %p instead of NULL", GET_PTR(e_key), 0);
- nbd_free(key);
- return hti_cas(hti, key_hash, key_data, key_len, expected, new); // tail-call
+ if (old_ent_key != DOES_NOT_EXIST) {
+ TRACE("h0", "hti_cas: lost race to install key %p in entry %p", new_key, ent);
+ TRACE("h0", "hti_cas: found %p instead of NULL",
+ (hti->ht->key_type == NULL) ? (void *)old_ent_key : GET_PTR(old_ent_key), 0);
+ if (hti->ht->key_type != NULL) {
+ nbd_free(GET_PTR(new_key));
+ }
+ return hti_cas(hti, key, key_hash, expected, new); // tail-call
}
- TRACE("h2", "hti_cas: installed key %p in entry %p", key, e);
+ TRACE("h2", "hti_cas: installed key %p in entry %p", new_key, ent);
}
- TRACE("h0", "hti_cas: entry for key \"%s\" is %p", GET_PTR(e->key)->data, e);
+ TRACE("h0", "hti_cas: entry for key %p is %p",
+ (hti->ht->key_type == NULL) ? (void *)ent->key : GET_PTR(ent->key), ent);
// If the entry is in the middle of a copy, the copy must be completed first.
- uint64_t e_value = e->value;
- if (EXPECT_FALSE(IS_TAGGED(e_value))) {
- if (e_value != COPIED_VALUE) {
- int did_copy = hti_copy_entry(hti, e, key_hash, ((volatile hashtable_i_t *)hti)->next);
+ uint64_t ent_val = ent->val;
+ if (EXPECT_FALSE(IS_TAGGED(ent_val, TAG1))) {
+ if (ent_val != COPIED_VALUE) {
+ int did_copy = hti_copy_entry(hti, ent, key_hash, ((volatile hti_t *)hti)->next);
if (did_copy) {
SYNC_ADD(&hti->num_entries_copied, 1);
}
}
// Fail if the old value is not consistent with the caller's expectation.
- int old_existed = (e_value != TOMBSTONE && e_value != DOES_NOT_EXIST);
- if (EXPECT_FALSE(expected != CAS_EXPECT_WHATEVER && expected != e_value)) {
+ int old_existed = (ent_val != TOMBSTONE && ent_val != DOES_NOT_EXIST);
+ if (EXPECT_FALSE(expected != CAS_EXPECT_WHATEVER && expected != ent_val)) {
if (EXPECT_FALSE(expected != (old_existed ? CAS_EXPECT_EXISTS : CAS_EXPECT_DOES_NOT_EXIST))) {
TRACE("h1", "hti_cas: value %p expected by caller not found; found value %p",
- expected, e_value);
- return e_value;
+ expected, ent_val);
+ return ent_val;
}
}
// No need to update if value is unchanged.
- if ((new == TOMBSTONE && !old_existed) || e_value == new) {
+ if ((new == DOES_NOT_EXIST && !old_existed) || ent_val == new) {
TRACE("h1", "hti_cas: old value and new value were the same", 0, 0);
- return e_value;
+ return ent_val;
}
// CAS the value into the entry. Retry if it fails.
- uint64_t v = SYNC_CAS(&e->value, e_value, new);
- if (EXPECT_FALSE(v != e_value)) {
- TRACE("h0", "hti_cas: value CAS failed; expected %p found %p", e_value, v);
- return hti_cas(hti, key_hash, key_data, key_len, expected, new); // recursive tail-call
+ uint64_t v = SYNC_CAS(&ent->val, ent_val, new == DOES_NOT_EXIST ? TOMBSTONE : new);
+ if (EXPECT_FALSE(v != ent_val)) {
+ TRACE("h0", "hti_cas: value CAS failed; expected %p found %p", ent_val, v);
+ return hti_cas(hti, key, key_hash, expected, new); // recursive tail-call
}
// The set succeeded. Adjust the value count.
- if (old_existed && new == TOMBSTONE) {
+ if (old_existed && new == DOES_NOT_EXIST) {
SYNC_ADD(&hti->count, -1);
- } else if (!old_existed && new != TOMBSTONE) {
+ } else if (!old_existed && new != DOES_NOT_EXIST) {
SYNC_ADD(&hti->count, 1);
}
// Return the previous value.
- TRACE("h0", "hti_cas: CAS succeeded; old value %p new value %p", e_value, new);
- return e_value;
+ TRACE("h0", "hti_cas: CAS succeeded; old value %p new value %p", ent_val, new);
+ return ent_val;
}
//
-static uint64_t hti_get (hashtable_i_t *hti, uint32_t key_hash, const char *key_data, uint32_t key_len) {
- assert(key_data);
-
+static uint64_t hti_get (hti_t *hti, void *key, uint32_t key_hash) {
int is_empty;
- volatile entry_t *e = hti_lookup(hti, key_hash, key_data, key_len, &is_empty);
+ volatile entry_t *ent = hti_lookup(hti, key, key_hash, &is_empty);
// When hti_lookup() returns NULL it means we hit the reprobe limit while
// searching the table. In that case, if a copy is in progress the key
// might exist in the copy.
- if (EXPECT_FALSE(e == NULL)) {
- if (((volatile hashtable_i_t *)hti)->next != NULL)
- return hti_get(hti->next, key_hash, key_data, key_len); // recursive tail-call
+ if (EXPECT_FALSE(ent == NULL)) {
+ if (((volatile hti_t *)hti)->next != NULL)
+ return hti_get(hti->next, key, key_hash); // recursive tail-call
return DOES_NOT_EXIST;
}
return DOES_NOT_EXIST;
// If the entry is being copied, finish the copy and retry on the next table.
- uint64_t e_value = e->value;
- if (EXPECT_FALSE(IS_TAGGED(e_value))) {
- if (EXPECT_FALSE(e_value != COPIED_VALUE)) {
- int did_copy = hti_copy_entry(hti, e, key_hash, ((volatile hashtable_i_t *)hti)->next);
+ uint64_t ent_val = ent->val;
+ if (EXPECT_FALSE(IS_TAGGED(ent_val, TAG1))) {
+ if (EXPECT_FALSE(ent_val != COPIED_VALUE)) {
+ int did_copy = hti_copy_entry(hti, ent, key_hash, ((volatile hti_t *)hti)->next);
if (did_copy) {
SYNC_ADD(&hti->num_entries_copied, 1);
}
}
- return hti_get(((volatile hashtable_i_t *)hti)->next, key_hash, key_data, key_len); // tail-call
+ return hti_get(((volatile hti_t *)hti)->next, key, key_hash); // tail-call
}
- return (e_value == TOMBSTONE) ? DOES_NOT_EXIST : e_value;
+ return (ent_val == TOMBSTONE) ? DOES_NOT_EXIST : ent_val;
}
//
-uint64_t ht_get (hashtable_t *ht, const char *key_data, uint32_t key_len) {
- return hti_get(ht->hti, murmur32(key_data, key_len), key_data, key_len);
+uint64_t ht_get (hashtable_t *ht, void *key) {
+ uint32_t hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash(key);
+ return hti_get(ht->hti, key, hash);
}
//
-uint64_t ht_cas (hashtable_t *ht, const char *key_data, uint32_t key_len, uint64_t expected_val, uint64_t new_val) {
+uint64_t ht_cas (hashtable_t *ht, void *key, uint64_t expected_val, uint64_t new_val) {
- TRACE("h2", "ht_cas: key %p len %u", key_data, key_len);
+ TRACE("h2", "ht_cas: key %p ht %p", key, ht);
TRACE("h2", "ht_cas: expected val %p new val %p", expected_val, new_val);
- assert(key_data);
- assert(!IS_TAGGED(new_val) && new_val != DOES_NOT_EXIST);
+ assert(key != DOES_NOT_EXIST);
+ assert(!IS_TAGGED(new_val, TAG1) && new_val != DOES_NOT_EXIST && new_val != TOMBSTONE);
- hashtable_i_t *hti = ht->hti;
+ hti_t *hti = ht->hti;
// Help with an ongoing copy.
if (EXPECT_FALSE(hti->next != NULL)) {
- volatile entry_t *e;
+ volatile entry_t *ent;
uint64_t limit;
int num_copied = 0;
int x = hti->scan;
// <hti->scan> might be larger than the size of the table, if some thread stalls while
// copying. In that case we just wrap around to the begining and make another pass through
// the table.
- e = hti->table + (x & MASK(hti->scale));
+ ent = hti->table + (x & MASK(hti->scale));
} else {
TRACE("h1", "ht_cas: help copy panic", 0, 0);
// scan the whole table
limit = (1 << hti->scale);
- e = hti->table;
+ ent = hti->table;
}
// Copy the entries
for (int i = 0; i < limit; ++i) {
- num_copied += hti_copy_entry(hti, e++, 0, hti->next);
- assert(e <= hti->table + (1 << hti->scale));
+ num_copied += hti_copy_entry(hti, ent++, 0, hti->next);
+ assert(ent <= hti->table + (1 << hti->scale));
}
if (num_copied != 0) {
SYNC_ADD(&hti->num_entries_copied, num_copied);
}
uint64_t old_val;
- uint32_t key_hash = murmur32(key_data, key_len);
- while ((old_val = hti_cas(hti, key_hash, key_data, key_len, expected_val, new_val))
- == COPIED_VALUE) {
+ uint32_t key_hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash(key);
+ while ((old_val = hti_cas(hti, key, key_hash, expected_val, new_val)) == COPIED_VALUE) {
assert(hti->next);
hti = hti->next;
}
return old_val == TOMBSTONE ? DOES_NOT_EXIST : old_val;
}
-// Remove the value in <ht> associated with <key_data>. Returns the value removed, or
-// DOES_NOT_EXIST if there was no value for that key.
-uint64_t ht_remove (hashtable_t *ht, const char *key_data, uint32_t key_len) {
- hashtable_i_t *hti = ht->hti;
+// Remove the value in <ht> associated with <key>. Returns the value removed, or DOES_NOT_EXIST if there was
+// no value for that key.
+uint64_t ht_remove (hashtable_t *ht, void *key) {
+ hti_t *hti = ht->hti;
uint64_t val;
- uint32_t key_hash = murmur32(key_data, key_len);
+ uint32_t key_hash = (ht->key_type == NULL) ? murmur32_8b((uint64_t)key) : ht->key_type->hash(key);
do {
- val = hti_cas(hti, key_hash, key_data, key_len, CAS_EXPECT_WHATEVER, TOMBSTONE);
+ val = hti_cas(hti, key, key_hash, CAS_EXPECT_WHATEVER, DOES_NOT_EXIST);
if (val != COPIED_VALUE)
return val == TOMBSTONE ? DOES_NOT_EXIST : val;
assert(hti->next);
// Returns the number of key-values pairs in <ht>
uint64_t ht_count (hashtable_t *ht) {
- hashtable_i_t *hti = ht->hti;
+ hti_t *hti = ht->hti;
uint64_t count = 0;
while (hti) {
count += hti->count;
}
// Allocate and initialize a new hash table.
-hashtable_t *ht_alloc (void) {
+hashtable_t *ht_alloc (const datatype_t *key_type) {
hashtable_t *ht = nbd_malloc(sizeof(hashtable_t));
- ht->hti = (hashtable_i_t *)hti_alloc(ht, MIN_SCALE);
+ ht->key_type = key_type;
+ ht->hti = (hti_t *)hti_alloc(ht, MIN_SCALE);
return ht;
}
// Free <ht> and its internal structures.
void ht_free (hashtable_t *ht) {
- hashtable_i_t *hti = ht->hti;
+ hti_t *hti = ht->hti;
do {
for (uint32_t i = 0; i < (1 << hti->scale); ++i) {
- assert(hti->table[i].value == COPIED_VALUE || !IS_TAGGED(hti->table[i].value));
- if (hti->table[i].key != DOES_NOT_EXIST) {
+ assert(hti->table[i].val == COPIED_VALUE || !IS_TAGGED(hti->table[i].val, TAG1));
+ if (ht->key_type != NULL && hti->table[i].key != DOES_NOT_EXIST) {
nbd_free(GET_PTR(hti->table[i].key));
}
}
- hashtable_i_t *next = hti->next;
+ hti_t *next = hti->next;
nbd_free(hti);
hti = next;
} while (hti);
}
void ht_print (hashtable_t *ht) {
+ hti_t *hti = ht->hti;
+ while (hti) {
+ printf("hti:%p scale:%u count:%d copied:%d\n", hti, hti->scale, hti->count, hti->num_entries_copied);
+ for (int i = 0; i < (1 << hti->scale); ++i) {
+ volatile entry_t *ent = hti->table + i;
+ printf("[0x%x] %p:%p\n", i, (void *)ent->key, (void *)ent->val);
+ if (i > 30) {
+ printf("...\n");
+ break;
+ }
+ }
+ hti = hti->next;
+ }
}
projects / nbds / blobdiff