Merging upstream version 1.16.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 60 insertions, 29 deletions

diff --git a/database/engine/pagecache.h b/database/engine/pagecache.h
index d1e29aaab..b5670f82a 100644
--- a/database/engine/pagecache.h
+++ b/database/engine/pagecache.h
@@ -5,9 +5,10 @@
 
 #include "rrdengine.h"
 
-/* Forward declerations */
+/* Forward declarations */
 struct rrdengine_instance;
 struct extent_info;
+struct rrdeng_page_descr;
 
 #define INVALID_TIME (0)
 
@@ -18,24 +19,46 @@ struct extent_info;
 #define RRD_PAGE_WRITE_PENDING  (1LU << 3)
 #define RRD_PAGE_POPULATED      (1LU << 4)
 
-struct rrdeng_page_cache_descr {
+struct page_cache_descr {
+    struct rrdeng_page_descr *descr; /* parent descriptor */
     void *page;
-    uint32_t page_length;
-    usec_t start_time;
-    usec_t end_time;
-    uuid_t *id; /* never changes */
-    struct extent_info *extent;
     unsigned long flags;
-    void *private;
-    struct rrdeng_page_cache_descr *prev;
-    struct rrdeng_page_cache_descr *next;
+    struct page_cache_descr *prev; /* LRU */
+    struct page_cache_descr *next; /* LRU */
 
-    /* TODO: move waiter logic to concurrency table */
     unsigned refcnt;
     uv_mutex_t mutex; /* always take it after the page cache lock or after the commit lock */
     uv_cond_t cond;
     unsigned waiters;
-    struct rrdeng_collect_handle *handle; /* API user */
+};
+
+/* Page cache descriptor flags, state = 0 means no descriptor */
+#define PG_CACHE_DESCR_ALLOCATED    (1LU << 0)
+#define PG_CACHE_DESCR_DESTROY      (1LU << 1)
+#define PG_CACHE_DESCR_LOCKED       (1LU << 2)
+#define PG_CACHE_DESCR_SHIFT        (3)
+#define PG_CACHE_DESCR_USERS_MASK   (((unsigned long)-1) << PG_CACHE_DESCR_SHIFT)
+#define PG_CACHE_DESCR_FLAGS_MASK   (((unsigned long)-1) >> (BITS_PER_ULONG - PG_CACHE_DESCR_SHIFT))
+
+/*
+ * Page cache descriptor state bits (works for both 32-bit and 64-bit architectures):
+ *
+ * 63    ...     31   ...     3 |          2 |          1 |          0|
+ * -----------------------------+------------+------------+-----------|
+ * number of descriptor users   |    DESTROY |     LOCKED | ALLOCATED |
+ */
+struct rrdeng_page_descr {
+    uint32_t page_length;
+    usec_t start_time;
+    usec_t end_time;
+    uuid_t *id; /* never changes */
+    struct extent_info *extent;
+
+    /* points to ephemeral page cache descriptor if the page resides in the cache */
+    struct page_cache_descr *pg_cache_descr;
+
+    /* Compare-And-Swap target for page cache descriptor allocation algorithm */
+    volatile unsigned long pg_cache_descr_state;
 };
 
 #define PAGE_CACHE_MAX_PRELOAD_PAGES    (256)
@@ -61,12 +84,15 @@ struct pg_cache_page_index {
      * It's also written by the data deletion workqueue when data collection is disabled for this metric.
      */
     usec_t latest_time;
+
+    struct pg_cache_page_index *prev;
 };
 
 /* maps UUIDs to page indices */
 struct pg_cache_metrics_index {
     uv_rwlock_t lock;
     Pvoid_t JudyHS_array;
+    struct pg_cache_page_index *last_page_index;
 };
 
 /* gathers dirty pages to be written on disk */
@@ -85,12 +111,15 @@ struct pg_cache_commited_page_index {
     unsigned nr_commited_pages;
 };
 
-/* gathers populated pages to be evicted */
+/*
+ * Gathers populated pages to be evicted.
+ * Relies on page cache descriptors being there as it uses their memory.
+ */
 struct pg_cache_replaceQ {
     uv_rwlock_t lock; /* LRU lock */
 
-    struct rrdeng_page_cache_descr *head; /* LRU */
-    struct rrdeng_page_cache_descr *tail; /* MRU */
+    struct page_cache_descr *head; /* LRU */
+    struct page_cache_descr *tail; /* MRU */
 };
 
 struct page_cache { /* TODO: add statistics */
@@ -104,29 +133,31 @@ struct page_cache { /* TODO: add statistics */
     unsigned populated_pages;
 };
 
-extern void pg_cache_wake_up_waiters_unsafe(struct rrdeng_page_cache_descr *descr);
-extern void pg_cache_wait_event_unsafe(struct rrdeng_page_cache_descr *descr);
-extern unsigned long pg_cache_wait_event(struct rrdeng_page_cache_descr *descr);
+extern void pg_cache_wake_up_waiters_unsafe(struct rrdeng_page_descr *descr);
+extern void pg_cache_wait_event_unsafe(struct rrdeng_page_descr *descr);
+extern unsigned long pg_cache_wait_event(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr);
 extern void pg_cache_replaceQ_insert(struct rrdengine_instance *ctx,
-                                     struct rrdeng_page_cache_descr *descr);
+                                     struct rrdeng_page_descr *descr);
 extern void pg_cache_replaceQ_delete(struct rrdengine_instance *ctx,
-                                     struct rrdeng_page_cache_descr *descr);
+                                     struct rrdeng_page_descr *descr);
 extern void pg_cache_replaceQ_set_hot(struct rrdengine_instance *ctx,
-                                      struct rrdeng_page_cache_descr *descr);
-extern struct rrdeng_page_cache_descr *pg_cache_create_descr(void);
-extern void pg_cache_put_unsafe(struct rrdeng_page_cache_descr *descr);
-extern void pg_cache_put(struct rrdeng_page_cache_descr *descr);
+                                      struct rrdeng_page_descr *descr);
+extern struct rrdeng_page_descr *pg_cache_create_descr(void);
+extern int pg_cache_try_get_unsafe(struct rrdeng_page_descr *descr, int exclusive_access);
+extern void pg_cache_put_unsafe(struct rrdeng_page_descr *descr);
+extern void pg_cache_put(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr);
 extern void pg_cache_insert(struct rrdengine_instance *ctx, struct pg_cache_page_index *index,
-                            struct rrdeng_page_cache_descr *descr);
-extern void pg_cache_punch_hole(struct rrdengine_instance *ctx, struct rrdeng_page_cache_descr *descr);
+                            struct rrdeng_page_descr *descr);
+extern void pg_cache_punch_hole(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr, uint8_t remove_dirty);
 extern struct pg_cache_page_index *
         pg_cache_preload(struct rrdengine_instance *ctx, uuid_t *id, usec_t start_time, usec_t end_time);
-extern struct rrdeng_page_cache_descr *
+extern struct rrdeng_page_descr *
         pg_cache_lookup(struct rrdengine_instance *ctx, struct pg_cache_page_index *index, uuid_t *id,
                         usec_t point_in_time);
 extern struct pg_cache_page_index *create_page_index(uuid_t *id);
 extern void init_page_cache(struct rrdengine_instance *ctx);
-extern void pg_cache_add_new_metric_time(struct pg_cache_page_index *page_index, struct rrdeng_page_cache_descr *descr);
+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);
 
-#endif /* NETDATA_PAGECACHE_H */
\ No newline at end of file
+#endif /* NETDATA_PAGECACHE_H */