diff options
Diffstat (limited to 'items.c')
| -rw-r--r-- | items.c | 142 |
1 files changed, 50 insertions, 92 deletions
@@ -99,124 +99,82 @@ item *do_item_alloc(char *key, const size_t nkey, const int flags, const rel_tim return 0; /* do a quick check if we have any expired items in the tail.. */ - int tries = 50; item *search; rel_time_t oldest_live = settings.oldest_live; - for (search = tails[id]; - tries > 0 && search != NULL; - tries--, search=search->prev) { - if (search->refcount == 0 && - ((search->time < oldest_live) || // dead by flush - (search->exptime != 0 && search->exptime < current_time))) { - it = search; - /* I don't want to actually free the object, just steal - * the item to avoid to grab the slab mutex twice ;-) - */ + search = tails[id]; + if (search == NULL) { + it = slabs_alloc(ntotal, id); + } else if (search->refcount == 0) { + if ((search->time < oldest_live) || // dead by flush + (search->exptime != 0 && search->exptime < current_time)) { STATS_LOCK(); stats.reclaimed++; STATS_UNLOCK(); itemstats[id].reclaimed++; - if ((it->it_flags & ITEM_FETCHED) == 0) { + if ((search->it_flags & ITEM_FETCHED) == 0) { STATS_LOCK(); stats.expired_unfetched++; STATS_UNLOCK(); itemstats[id].expired_unfetched++; } + it = search; it->refcount = 1; slabs_adjust_mem_requested(it->slabs_clsid, ITEM_ntotal(it), ntotal); do_item_unlink(it, hash(ITEM_key(it), it->nkey, 0)); /* Initialize the item block: */ it->slabs_clsid = 0; it->refcount = 0; - break; } } if (it == NULL && (it = slabs_alloc(ntotal, id)) == NULL) { - /* - ** Could not find an expired item at the tail, and memory allocation - ** failed. Try to evict some items! - */ - tries = 50; - - /* If requested to not push old items out of cache when memory runs out, - * we're out of luck at this point... - */ - - if (settings.evict_to_free == 0) { - itemstats[id].outofmemory++; - return NULL; + if (search->refcount == 0 && + (search->exptime == 0 || search->exptime > current_time)) { + if (settings.evict_to_free == 0) { + itemstats[id].outofmemory++; + return NULL; + } + itemstats[id].evicted++; + itemstats[id].evicted_time = current_time - search->time; + if (search->exptime != 0) + itemstats[id].evicted_nonzero++; + if ((search->it_flags & ITEM_FETCHED) == 0) { + STATS_LOCK(); + stats.evicted_unfetched++; + STATS_UNLOCK(); + itemstats[id].evicted_unfetched++; + } + STATS_LOCK(); + stats.evictions++; + STATS_UNLOCK(); + it = search; + it->refcount = 1; + slabs_adjust_mem_requested(it->slabs_clsid, ITEM_ntotal(it), ntotal); + do_item_unlink(it, hash(ITEM_key(it), it->nkey, 0)); + /* Initialize the item block: */ + it->slabs_clsid = 0; + it->refcount = 0; } + } - /* - * try to get one off the right LRU - * don't necessariuly unlink the tail because it may be locked: refcount>0 - * search up from tail an item with refcount==0 and unlink it; give up after 50 - * tries + if (it == NULL) { + itemstats[id].outofmemory++; + /* Last ditch effort. There is a very rare bug which causes + * refcount leaks. We've fixed most of them, but it still happens, + * and it may happen in the future. + * We can reasonably assume no item can stay locked for more than + * three hours, so if we find one in the tail which is that old, + * free it anyway. */ - - if (tails[id] == 0) { - itemstats[id].outofmemory++; - return NULL; - } - - for (search = tails[id]; tries > 0 && search != NULL; tries--, search=search->prev) { - if (search->refcount == 0) { - if (search->exptime == 0 || search->exptime > current_time) { - itemstats[id].evicted++; - itemstats[id].evicted_time = current_time - search->time; - if (search->exptime != 0) - itemstats[id].evicted_nonzero++; - if ((search->it_flags & ITEM_FETCHED) == 0) { - STATS_LOCK(); - stats.evicted_unfetched++; - STATS_UNLOCK(); - itemstats[id].evicted_unfetched++; - } - STATS_LOCK(); - stats.evictions++; - STATS_UNLOCK(); - } else { - itemstats[id].reclaimed++; - STATS_LOCK(); - stats.reclaimed++; - STATS_UNLOCK(); - if ((search->it_flags & ITEM_FETCHED) == 0) { - STATS_LOCK(); - stats.expired_unfetched++; - STATS_UNLOCK(); - itemstats[id].expired_unfetched++; - } - } - do_item_unlink(search, hash(ITEM_key(search), search->nkey, 0)); - break; - } - } - it = slabs_alloc(ntotal, id); - if (it == 0) { - itemstats[id].outofmemory++; - /* Last ditch effort. There is a very rare bug which causes - * refcount leaks. We've fixed most of them, but it still happens, - * and it may happen in the future. - * We can reasonably assume no item can stay locked for more than - * three hours, so if we find one in the tail which is that old, - * free it anyway. - */ - tries = 50; - for (search = tails[id]; tries > 0 && search != NULL; tries--, search=search->prev) { - if (search->refcount != 0 && search->time + TAIL_REPAIR_TIME < current_time) { - itemstats[id].tailrepairs++; - search->refcount = 0; - do_item_unlink(search, hash(ITEM_key(search), search->nkey, 0)); - break; - } - } - it = slabs_alloc(ntotal, id); - if (it == 0) { - return NULL; - } + if (search != NULL && + search->refcount != 0 && + search->time + TAIL_REPAIR_TIME < current_time) { + itemstats[id].tailrepairs++; + search->refcount = 0; + do_item_unlink(search, hash(ITEM_key(search), search->nkey, 0)); } + return NULL; } assert(it->slabs_clsid == 0); |