Adding upstream version 1.29.3.upstream/1.29.3upstream

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

1 files changed, 231 insertions, 0 deletions

diff --git a/database/engine/pagecache.h b/database/engine/pagecache.h
new file mode 100644
index 0000000..31e9739
--- /dev/null
+++ b/database/engine/pagecache.h
@@ -0,0 +1,231 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef NETDATA_PAGECACHE_H
+#define NETDATA_PAGECACHE_H
+
+#include "rrdengine.h"
+
+/* Forward declarations */
+struct rrdengine_instance;
+struct extent_info;
+struct rrdeng_page_descr;
+
+#define INVALID_TIME (0)
+
+/* Page flags */
+#define RRD_PAGE_DIRTY          (1LU << 0)
+#define RRD_PAGE_LOCKED         (1LU << 1)
+#define RRD_PAGE_READ_PENDING   (1LU << 2)
+#define RRD_PAGE_WRITE_PENDING  (1LU << 3)
+#define RRD_PAGE_POPULATED      (1LU << 4)
+
+struct page_cache_descr {
+    struct rrdeng_page_descr *descr; /* parent descriptor */
+    void *page;
+    unsigned long flags;
+    struct page_cache_descr *prev; /* LRU */
+    struct page_cache_descr *next; /* LRU */
+
+    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;
+};
+
+/* 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 {
+    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;
+
+    /* page information */
+    usec_t start_time;
+    usec_t end_time;
+    uint32_t page_length;
+};
+
+#define PAGE_INFO_SCRATCH_SZ (8)
+struct rrdeng_page_info {
+    uint8_t scratch[PAGE_INFO_SCRATCH_SZ]; /* scratch area to be used by page-cache users */
+
+    usec_t start_time;
+    usec_t end_time;
+    uint32_t page_length;
+};
+
+/* returns 1 for success, 0 for failure */
+typedef int pg_cache_page_info_filter_t(struct rrdeng_page_descr *);
+
+#define PAGE_CACHE_MAX_PRELOAD_PAGES    (256)
+
+/* maps time ranges to pages */
+struct pg_cache_page_index {
+    uuid_t id;
+    /*
+     * care: JudyL_array indices are converted from useconds to seconds to fit in one word in 32-bit architectures
+     * TODO: examine if we want to support better granularity than seconds
+     */
+    Pvoid_t JudyL_array;
+    Word_t page_count;
+    unsigned short writers;
+    uv_rwlock_t lock;
+
+    /*
+     * Only one effective writer, data deletion workqueue.
+     * It's also written during the DB loading phase.
+     */
+    usec_t oldest_time;
+
+    /*
+     * Only one effective writer, data collection thread.
+     * 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 */
+struct pg_cache_committed_page_index {
+    uv_rwlock_t lock;
+
+    Pvoid_t JudyL_array;
+
+    /*
+     * Dirty page correlation ID is a hint. Dirty pages that are correlated should have
+     * a small correlation ID difference. Dirty pages in memory should never have the
+     * same ID at the same time for correctness.
+     */
+    Word_t latest_corr_id;
+
+    unsigned nr_committed_pages;
+};
+
+/*
+ * 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 page_cache_descr *head; /* LRU */
+    struct page_cache_descr *tail; /* MRU */
+};
+
+struct page_cache { /* TODO: add statistics */
+    uv_rwlock_t pg_cache_rwlock; /* page cache lock */
+
+    struct pg_cache_metrics_index metrics_index;
+    struct pg_cache_committed_page_index committed_page_index;
+    struct pg_cache_replaceQ replaceQ;
+
+    unsigned page_descriptors;
+    unsigned populated_pages;
+};
+
+extern void pg_cache_wake_up_waiters_unsafe(struct rrdeng_page_descr *descr);
+extern void pg_cache_wake_up_waiters(struct rrdengine_instance *ctx, 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_descr *descr);
+extern void pg_cache_replaceQ_delete(struct rrdengine_instance *ctx,
+                                     struct rrdeng_page_descr *descr);
+extern void pg_cache_replaceQ_set_hot(struct rrdengine_instance *ctx,
+                                      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_descr *descr);
+extern uint8_t pg_cache_punch_hole(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr,
+                                   uint8_t remove_dirty, uint8_t is_exclusive_holder, uuid_t *metric_id);
+extern usec_t pg_cache_oldest_time_in_range(struct rrdengine_instance *ctx, uuid_t *id,
+                                            usec_t start_time, usec_t end_time);
+extern void pg_cache_get_filtered_info_prev(struct rrdengine_instance *ctx, struct pg_cache_page_index *page_index,
+                                            usec_t point_in_time, pg_cache_page_info_filter_t *filter,
+                                            struct rrdeng_page_info *page_info);
+extern unsigned
+        pg_cache_preload(struct rrdengine_instance *ctx, uuid_t *id, usec_t start_time, usec_t end_time,
+                         struct rrdeng_page_info **page_info_arrayp, struct pg_cache_page_index **ret_page_indexp);
+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 rrdeng_page_descr *
+        pg_cache_lookup_next(struct rrdengine_instance *ctx, struct pg_cache_page_index *index, uuid_t *id,
+                     usec_t start_time, usec_t end_time);
+extern struct pg_cache_page_index *create_page_index(uuid_t *id);
+extern void init_page_cache(struct rrdengine_instance *ctx);
+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);
+extern unsigned long pg_cache_hard_limit(struct rrdengine_instance *ctx);
+extern unsigned long pg_cache_soft_limit(struct rrdengine_instance *ctx);
+extern unsigned long pg_cache_committed_hard_limit(struct rrdengine_instance *ctx);
+
+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)
+{
+    fatal_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 */