diff options
| -rw-r--r-- | doc/protocol.txt | 3 | ||||
| -rw-r--r-- | items.c | 24 |
2 files changed, 26 insertions, 1 deletions
diff --git a/doc/protocol.txt b/doc/protocol.txt index 6dd4cf6..6ce04eb 100644 --- a/doc/protocol.txt +++ b/doc/protocol.txt @@ -478,6 +478,9 @@ evicted_time Seconds since the last access for the most recent item outofmemory Number of times the underlying slab class was unable to store a new item. This means you are running with -M or an eviction failed. +tailrepairs Number of times we self-healed a slab with a refcount + leak. If this counter is increasing a lot, please + report your situation to the developers. Note this will only display information about slabs which exist, so an empty cache will return an empty set. @@ -29,6 +29,7 @@ typedef struct { unsigned int evicted; rel_time_t evicted_time; unsigned int outofmemory; + unsigned int tailrepairs; } itemstats_t; static item *heads[LARGEST_ID]; @@ -169,7 +170,26 @@ item *do_item_alloc(char *key, const size_t nkey, const int flags, const rel_tim it = slabs_alloc(ntotal, id); if (it == 0) { itemstats[id].outofmemory++; - return NULL; + /* 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 + 10800 < current_time) { + itemstats[id].tailrepairs++; + search->refcount = 0; + do_item_unlink(search); + break; + } + } + it = slabs_alloc(ntotal, id); + if (it == 0) { + return NULL; + } } } @@ -402,6 +422,8 @@ char *do_item_stats(uint32_t (*add_stats)(char *buf, "%u", itemstats[i].evicted_time); APPEND_NUM_FMT_STAT(fmt, i, "outofmemory", "%u", itemstats[i].outofmemory); + APPEND_NUM_FMT_STAT(fmt, i, "tailrepairs", + "%u", itemstats[i].tailrepairs);; /* check whether binary protocol terminator will fit */ if (*buflen + hdrsiz > allocated) { |