diff options
Diffstat (limited to 'database/engine/pagecache.h')
| -rw-r--r-- | database/engine/pagecache.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/database/engine/pagecache.h b/database/engine/pagecache.h index d464211e9..ab1a5c1ad 100644 --- a/database/engine/pagecache.h +++ b/database/engine/pagecache.h @@ -183,4 +183,42 @@ extern void free_page_cache(struct rrdengine_instance *ctx); extern void pg_cache_add_new_metric_time(struct pg_cache_page_index *page_index, struct rrdeng_page_descr *descr); extern void pg_cache_update_metric_times(struct pg_cache_page_index *page_index); +static inline void + pg_cache_atomic_get_pg_info(struct rrdeng_page_descr *descr, usec_t *end_timep, uint32_t *page_lengthp) +{ + usec_t end_time, old_end_time; + uint32_t page_length; + + if (NULL == descr->extent) { + /* this page is currently being modified, get consistent info locklessly */ + do { + end_time = descr->end_time; + __sync_synchronize(); + old_end_time = end_time; + page_length = descr->page_length; + __sync_synchronize(); + end_time = descr->end_time; + __sync_synchronize(); + } while ((end_time != old_end_time || (end_time & 1) != 0)); + + *end_timep = end_time; + *page_lengthp = page_length; + } else { + *end_timep = descr->end_time; + *page_lengthp = descr->page_length; + } +} + +/* The caller must hold a reference to the page and must have already set the new data */ +static inline void pg_cache_atomic_set_pg_info(struct rrdeng_page_descr *descr, usec_t end_time, uint32_t page_length) +{ + assert(!(end_time & 1)); + __sync_synchronize(); + descr->end_time |= 1; /* mark start of uncertainty period by adding 1 microsecond */ + __sync_synchronize(); + descr->page_length = page_length; + __sync_synchronize(); + descr->end_time = end_time; /* mark end of uncertainty period */ +} + #endif /* NETDATA_PAGECACHE_H */ |