| 68,8 → 68,23 |
|---|
| link_t freed_head; |
| } unused_t; |
| |
| /** Futex protecting the list of unused structures. */ |
| static futex_t unused_futex = FUTEX_INITIALIZER; |
| |
| /** List of unused structures. */ |
| static LIST_INITIALIZE(unused_head); |
| |
| /** Futex protecting the up_hash and ui_hash. |
| * |
| * The locking strategy assumes that there will be at most one fibril for each |
| * dev_handle. Therefore it will be sufficient to hold the futex for shorter |
| * times (i.e. only during hash table operations as opposed to holding it the |
| * whole time between an unsuccessful find and the following insert). Should the |
| * assumption break, the locking strategy for this futex will have to be |
| * reconsidered. |
| */ |
| static futex_t used_futex = FUTEX_INITIALIZER; |
| |
| /** |
| * Global hash table of all used fat_idx_t structures. |
| * The index structures are hashed by the dev_handle, parent node's first |
| 187,12 → 202,14 |
|---|
| unused_t *u; |
| |
| assert(index); |
| futex_down(&unused_futex); |
| for (l = unused_head.next; l != &unused_head; l = l->next) { |
| u = list_get_instance(l, unused_t, link); |
| if (u->dev_handle == dev_handle) |
| goto hit; |
| } |
| |
| futex_up(&unused_futex); |
| |
| /* dev_handle not found */ |
| return false; |
| |
| 205,6 → 222,7 |
|---|
| */ |
| *index = u->next++; |
| --u->remaining; |
| futex_up(&unused_futex); |
| return true; |
| } |
| } else { |
| 217,6 → 235,7 |
|---|
| list_remove(&f->link); |
| free(f); |
| } |
| futex_up(&unused_futex); |
| return true; |
| } |
| /* |
| 224,6 → 243,7 |
|---|
| * theoretically still possible (e.g. too many open unlinked nodes or |
| * too many zero-sized nodes). |
| */ |
| futex_up(&unused_futex); |
| return false; |
| } |
| |
| 252,11 → 272,13 |
|---|
| link_t *l; |
| unused_t *u; |
| |
| futex_down(&unused_futex); |
| for (l = unused_head.next; l != &unused_head; l = l->next) { |
| u = list_get_instance(l, unused_t, link); |
| if (u->dev_handle == dev_handle) |
| goto hit; |
| } |
| futex_up(&unused_futex); |
| |
| /* should not happen */ |
| assert(0); |
| 266,7 → 288,6 |
|---|
| /* The index can be returned directly to the counter. */ |
| u->next--; |
| u->remaining++; |
| return; |
| } else { |
| /* |
| * The index must be returned either to an existing freed |
| 282,6 → 303,7 |
|---|
| if (lnk->prev != &u->freed_head) |
| try_coalesce_intervals(lnk->prev, lnk, |
| lnk); |
| futex_up(&unused_futex); |
| return; |
| } |
| if (f->last == index - 1) { |
| 289,6 → 311,7 |
|---|
| if (lnk->next != &u->freed_head) |
| try_coalesce_intervals(lnk, lnk->next, |
| lnk); |
| futex_up(&unused_futex); |
| return; |
| } |
| if (index > f->first) { |
| 299,6 → 322,7 |
|---|
| n->first = index; |
| n->last = index; |
| list_insert_before(&n->link, lnk); |
| futex_up(&unused_futex); |
| return; |
| } |
| |
| 312,6 → 336,7 |
|---|
| n->last = index; |
| list_append(&n->link, &u->freed_head); |
| } |
| futex_up(&unused_futex); |
| } |
| |
| fat_idx_t * |
| 325,7 → 350,9 |
|---|
| [UPH_PDI_KEY] = pdi, |
| }; |
| |
| futex_down(&used_futex); |
| l = hash_table_find(&up_hash, pkey); |
| futex_up(&used_futex); |
| if (l) { |
| fidx = hash_table_get_instance(l, fat_idx_t, uph_link); |
| } else { |
| 350,8 → 377,10 |
|---|
| fidx->pdi = pdi; |
| fidx->nodep = NULL; |
| |
| futex_down(&used_futex); |
| hash_table_insert(&up_hash, pkey, &fidx->uph_link); |
| hash_table_insert(&ui_hash, ikey, &fidx->uih_link); |
| futex_up(&used_futex); |
| } |
| |
| return fidx; |
| 367,7 → 396,9 |
|---|
| [UIH_INDEX_KEY] = index, |
| }; |
| |
| futex_down(&used_futex); |
| l = hash_table_find(&ui_hash, ikey); |
| futex_up(&used_futex); |
| if (l) { |
| fidx = hash_table_get_instance(l, fat_idx_t, uih_link); |
| } |