/*
DESCRIPTION
deletes an element with the given key from the hash (if a hash is
not unique and there're many elements with this key - the "first"
matching element is deleted)
RETURN
0 - deleted
1 - didn't (not found)
-1 - out of memory
NOTE
see ldelete() for pin usage notes
*/
int lf_hash_delete(LF_HASH *hash, LF_PINS *pins, const void *key, uint keylen)
{
LF_SLIST * volatile *el;
uint bucket, hashnr= calc_hash(hash, (uchar *)key, keylen);
bucket= hashnr % hash->size;
lf_rwlock_by_pins(pins);
el= _lf_dynarray_lvalue(&hash->array, bucket);
if (unlikely(!el))
return -1;
/*
note that we still need to initialize_bucket here,
we cannot return "node not found", because an old bucket of that
node may've been split and the node was assigned to a new bucket
that was never accessed before and thus is not initialized.
*/
if (*el == NULL && unlikely(initialize_bucket(hash, el, bucket, pins)))
return -1;
if (ldelete(el, hash->charset, my_reverse_bits(hashnr) | 1,
(uchar *)key, keylen, pins))
{
lf_rwunlock_by_pins(pins);
return 1;
}
my_atomic_add32(&hash->count, -1);
lf_rwunlock_by_pins(pins);
return 0;
}
/*
Allocate and return an new object.
DESCRIPTION
Pop an unused object from the stack or malloc it is the stack is empty.
pin[0] is used, it's removed on return.
*/
void *_lf_alloc_new(LF_PINS *pins)
{
LF_ALLOCATOR *allocator= (LF_ALLOCATOR *)(pins->pinbox->free_func_arg);
uchar *node;
for (;;)
{
do
{
node= allocator->top;
_lf_pin(pins, 0, node);
} while (node != allocator->top && LF_BACKOFF);
if (!node)
{
node= (void *)my_malloc(allocator->element_size, MYF(MY_WME));
if (allocator->constructor)
allocator->constructor(node);
#ifdef MY_LF_EXTRA_DEBUG
if (likely(node != 0))
my_atomic_add32(&allocator->mallocs, 1);
#endif
break;
}
if (my_atomic_casptr((void **)(char *)&allocator->top,
(void *)&node, anext_node(node)))
break;
}
_lf_unpin(pins, 0);
return node;
}
/*
DESCRIPTION
inserts a new element to a hash. it will have a _copy_ of
data, not a pointer to it.
RETURN
0 - inserted
1 - didn't (unique key conflict)
-1 - out of memory
NOTE
see linsert() for pin usage notes
*/
int lf_hash_insert(LF_HASH *hash, LF_PINS *pins, const void *data)
{
int csize, bucket, hashnr;
LF_SLIST *node, * volatile *el;
lf_rwlock_by_pins(pins);
node= (LF_SLIST *)_lf_alloc_new(pins);
if (unlikely(!node))
return -1;
memcpy(node+1, data, hash->element_size);
node->key= hash_key(hash, (uchar *)(node+1), &node->keylen);
hashnr= calc_hash(hash, node->key, node->keylen);
bucket= hashnr % hash->size;
el= _lf_dynarray_lvalue(&hash->array, bucket);
if (unlikely(!el))
return -1;
if (*el == NULL && unlikely(initialize_bucket(hash, el, bucket, pins)))
return -1;
node->hashnr= my_reverse_bits(hashnr) | 1; /* normal node */
if (linsert(el, hash->charset, node, pins, hash->flags))
{
_lf_alloc_free(pins, node);
lf_rwunlock_by_pins(pins);
return 1;
}
csize= hash->size;
if ((my_atomic_add32(&hash->count, 1)+1.0) / csize > MAX_LOAD)
my_atomic_cas32(&hash->size, &csize, csize*2);
lf_rwunlock_by_pins(pins);
return 0;
}
/* add and sub a random number in a loop. Must get 0 at the end */
pthread_handler_t test_atomic_add(void *arg)
{
int m= (*(int *)arg)/2;
GCC_BUG_WORKAROUND int32 x;
for (x= ((int)(intptr)(&m)); m ; m--)
{
x= (x*m+0x87654321) & INT_MAX32;
my_atomic_rwlock_wrlock(&rwl);
my_atomic_add32(&bad, x);
my_atomic_rwlock_wrunlock(&rwl);
my_atomic_rwlock_wrlock(&rwl);
my_atomic_add32(&bad, -x);
my_atomic_rwlock_wrunlock(&rwl);
}
pthread_mutex_lock(&mutex);
if (!--running_threads) pthread_cond_signal(&cond);
pthread_mutex_unlock(&mutex);
return 0;
}
/*
Get pins from a pinbox. Usually called via lf_alloc_get_pins() or
lf_hash_get_pins().
SYNOPSYS
pinbox -
DESCRIPTION
get a new LF_PINS structure from a stack of unused pins,
or allocate a new one out of dynarray.
NOTE
It is assumed that pins belong to a thread and are not transferable
between threads.
*/
LF_PINS *_lf_pinbox_get_pins(LF_PINBOX *pinbox)
{
struct st_my_thread_var *var;
uint32 pins, next, top_ver;
LF_PINS *el;
/*
We have an array of max. 64k elements.
The highest index currently allocated is pinbox->pins_in_array.
Freed elements are in a lifo stack, pinstack_top_ver.
pinstack_top_ver is 32 bits; 16 low bits are the index in the
array, to the first element of the list. 16 high bits are a version
(every time the 16 low bits are updated, the 16 high bits are
incremented). Versioniong prevents the ABA problem.
*/
top_ver= pinbox->pinstack_top_ver;
do
{
if (!(pins= top_ver % LF_PINBOX_MAX_PINS))
{
/* the stack of free elements is empty */
pins= my_atomic_add32((int32 volatile*) &pinbox->pins_in_array, 1)+1;
if (unlikely(pins >= LF_PINBOX_MAX_PINS))
return 0;
/*
note that the first allocated element has index 1 (pins==1).
index 0 is reserved to mean "NULL pointer"
*/
el= (LF_PINS *)_lf_dynarray_lvalue(&pinbox->pinarray, pins);
if (unlikely(!el))
return 0;
break;
}
el= (LF_PINS *)_lf_dynarray_value(&pinbox->pinarray, pins);
next= el->link;
} while (!my_atomic_cas32((int32 volatile*) &pinbox->pinstack_top_ver,
(int32*) &top_ver,
top_ver-pins+next+LF_PINBOX_MAX_PINS));
/*
set el->link to the index of el in the dynarray (el->link has two usages:
- if element is allocated, it's its own index
- if element is free, it's its next element in the free stack
*/
el->link= pins;
el->purgatory_count= 0;
el->pinbox= pinbox;
var= my_thread_var;
/*
Threads that do not call my_thread_init() should still be
able to use the LF_HASH.
*/
el->stack_ends_here= (var ? & var->stack_ends_here : NULL);
return el;
}
/*
1. generate thread number 0..N-1 from b32
2. add it to bad
3. swap thread numbers in c32
4. (optionally) one more swap to avoid 0 as a result
5. subtract result from bad
must get 0 in bad at the end
*/
pthread_handler_t test_atomic_fas(void *arg)
{
int m= *(int *)arg;
int32 x;
my_atomic_rwlock_wrlock(&rwl);
x= my_atomic_add32(&b32, 1);
my_atomic_rwlock_wrunlock(&rwl);
my_atomic_rwlock_wrlock(&rwl);
my_atomic_add32(&bad, x);
my_atomic_rwlock_wrunlock(&rwl);
for (; m ; m--)
{
my_atomic_rwlock_wrlock(&rwl);
x= my_atomic_fas32(&c32, x);
my_atomic_rwlock_wrunlock(&rwl);
}
if (!x)
{
my_atomic_rwlock_wrlock(&rwl);
x= my_atomic_fas32(&c32, x);
my_atomic_rwlock_wrunlock(&rwl);
}
my_atomic_rwlock_wrlock(&rwl);
my_atomic_add32(&bad, -x);
my_atomic_rwlock_wrunlock(&rwl);
pthread_mutex_lock(&mutex);
if (!--running_threads) pthread_cond_signal(&cond);
pthread_mutex_unlock(&mutex);
return 0;
}
/*
DESCRIPTION
deletes an element with the given key from the hash (if a hash is
not unique and there're many elements with this key - the "first"
matching element is deleted)
RETURN
0 - deleted
1 - didn't (not found)
NOTE
see l_delete() for pin usage notes
*/
int lf_hash_delete(LF_HASH *hash, LF_PINS *pins, const void *key, uint keylen)
{
LF_SLIST * volatile *el;
uint bucket, hashnr;
hashnr= hash->hash_function(hash->charset, (uchar *)key, keylen) & INT_MAX32;
/* hide OOM errors - if we cannot initalize a bucket, try the previous one */
for (bucket= hashnr % hash->size; ;bucket= my_clear_highest_bit(bucket))
{
el= lf_dynarray_lvalue(&hash->array, bucket);
if (el && (*el || initialize_bucket(hash, el, bucket, pins) == 0))
break;
if (unlikely(bucket == 0))
return 1; /* if there's no bucket==0, the hash is empty */
}
if (l_delete(el, hash->charset, my_reverse_bits(hashnr) | 1,
(uchar *)key, keylen, pins))
{
return 1;
}
my_atomic_add32(&hash->count, -1);
return 0;
}
