On 29/05/16 22:52, Sergey Fedorov wrote:
> On 25/05/16 04:13, Emilio G. Cota wrote:
>> +
>> +/* call with head->lock held */
>> +static bool qht_insert__locked(struct qht *ht, struct qht_map *map,
>> + struct qht_bucket *head, void *p, uint32_t
>> hash,
>> + bool *needs_resize)
>> +{
>> + struct qht_bucket *b = head;
>> + struct qht_bucket *prev = NULL;
>> + struct qht_bucket *new = NULL;
>> + int i;
>> +
>> + for (;;) {
>> + if (b == NULL) {
>> + b = qemu_memalign(QHT_BUCKET_ALIGN, sizeof(*b));
>> + memset(b, 0, sizeof(*b));
>> + new = b;
>> + atomic_inc(&map->n_added_buckets);
>> + if (unlikely(qht_map_needs_resize(map)) && needs_resize) {
>> + *needs_resize = true;
>> + }
>> + }
>> + for (i = 0; i < QHT_BUCKET_ENTRIES; i++) {
>> + if (b->pointers[i]) {
>> + if (unlikely(b->pointers[i] == p)) {
>> + return false;
>> + }
>> + continue;
>> + }
>> + /* found an empty key: acquire the seqlock and write */
>> + seqlock_write_begin(&head->sequence);
>> + if (new) {
>> + atomic_rcu_set(&prev->next, b);
>> + }
>> + b->hashes[i] = hash;
>> + atomic_set(&b->pointers[i], p);
>> + seqlock_write_end(&head->sequence);
>> + return true;
>> + }
>> + prev = b;
>> + b = b->next;
>> + }
>> +}
> Here is my attempt:
static bool qht_insert__locked(struct qht *ht, struct qht_map *map,
struct qht_bucket *head, void *p,
uint32_t hash,
bool *needs_resize)
{
struct qht_bucket **bpp = &head, *new;
int i = 0;
do {
while (i < QHT_BUCKET_ENTRIES) {
if ((*bpp)->pointers[i]) {
if (unlikely((*bpp)->pointers[i] == p)) {
return false;
}
i++;
continue;
}
goto found;
}
bpp = &(*bpp)->next;
i = 0;
} while (*bpp);
new = qemu_memalign(QHT_BUCKET_ALIGN, sizeof(*new));
memset(new, 0, sizeof(*new));
atomic_rcu_set(bpp, new);
atomic_inc(&map->n_added_buckets);
if (unlikely(qht_map_needs_resize(map)) && needs_resize) {
*needs_resize = true;
}
found:
/* found an empty key: acquire the seqlock and write */
seqlock_write_begin(&head->sequence);
(*bpp)->hashes[i] = hash;
atomic_set(&(*bpp)->pointers[i], p);
seqlock_write_end(&head->sequence);
return true;
}
> Feel free to use it as you wish.
Sorry for the chopped email. Hope this one will be better :)
Kind regards,
Sergey
