diff options
Diffstat (limited to 'database/engine/pagecache.c')
| -rw-r--r-- | database/engine/pagecache.c | 1178 |
1 files changed, 1178 insertions, 0 deletions
diff --git a/database/engine/pagecache.c b/database/engine/pagecache.c new file mode 100644 index 0000000..a182071 --- /dev/null +++ b/database/engine/pagecache.c @@ -0,0 +1,1178 @@ +// SPDX-License-Identifier: GPL-3.0-or-later +#define NETDATA_RRD_INTERNALS + +#include "rrdengine.h" + +/* Forward declerations */ +static int pg_cache_try_evict_one_page_unsafe(struct rrdengine_instance *ctx); + +/* always inserts into tail */ +static inline void pg_cache_replaceQ_insert_unsafe(struct rrdengine_instance *ctx, + struct rrdeng_page_descr *descr) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + if (likely(NULL != pg_cache->replaceQ.tail)) { + pg_cache_descr->prev = pg_cache->replaceQ.tail; + pg_cache->replaceQ.tail->next = pg_cache_descr; + } + if (unlikely(NULL == pg_cache->replaceQ.head)) { + pg_cache->replaceQ.head = pg_cache_descr; + } + pg_cache->replaceQ.tail = pg_cache_descr; +} + +static inline void pg_cache_replaceQ_delete_unsafe(struct rrdengine_instance *ctx, + struct rrdeng_page_descr *descr) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr, *prev, *next; + + prev = pg_cache_descr->prev; + next = pg_cache_descr->next; + + if (likely(NULL != prev)) { + prev->next = next; + } + if (likely(NULL != next)) { + next->prev = prev; + } + if (unlikely(pg_cache_descr == pg_cache->replaceQ.head)) { + pg_cache->replaceQ.head = next; + } + if (unlikely(pg_cache_descr == pg_cache->replaceQ.tail)) { + pg_cache->replaceQ.tail = prev; + } + pg_cache_descr->prev = pg_cache_descr->next = NULL; +} + +void pg_cache_replaceQ_insert(struct rrdengine_instance *ctx, + struct rrdeng_page_descr *descr) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + uv_rwlock_wrlock(&pg_cache->replaceQ.lock); + pg_cache_replaceQ_insert_unsafe(ctx, descr); + uv_rwlock_wrunlock(&pg_cache->replaceQ.lock); +} + +void pg_cache_replaceQ_delete(struct rrdengine_instance *ctx, + struct rrdeng_page_descr *descr) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + uv_rwlock_wrlock(&pg_cache->replaceQ.lock); + pg_cache_replaceQ_delete_unsafe(ctx, descr); + uv_rwlock_wrunlock(&pg_cache->replaceQ.lock); +} +void pg_cache_replaceQ_set_hot(struct rrdengine_instance *ctx, + struct rrdeng_page_descr *descr) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + uv_rwlock_wrlock(&pg_cache->replaceQ.lock); + pg_cache_replaceQ_delete_unsafe(ctx, descr); + pg_cache_replaceQ_insert_unsafe(ctx, descr); + uv_rwlock_wrunlock(&pg_cache->replaceQ.lock); +} + +struct rrdeng_page_descr *pg_cache_create_descr(void) +{ + struct rrdeng_page_descr *descr; + + descr = mallocz(sizeof(*descr)); + descr->page_length = 0; + descr->start_time = INVALID_TIME; + descr->end_time = INVALID_TIME; + descr->id = NULL; + descr->extent = NULL; + descr->pg_cache_descr_state = 0; + descr->pg_cache_descr = NULL; + + return descr; +} + +/* The caller must hold page descriptor lock. */ +void pg_cache_wake_up_waiters_unsafe(struct rrdeng_page_descr *descr) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + if (pg_cache_descr->waiters) + uv_cond_broadcast(&pg_cache_descr->cond); +} + +void pg_cache_wake_up_waiters(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr) +{ + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_wake_up_waiters_unsafe(descr); + rrdeng_page_descr_mutex_unlock(ctx, descr); +} + +/* + * The caller must hold page descriptor lock. + * The lock will be released and re-acquired. The descriptor is not guaranteed + * to exist after this function returns. + */ +void pg_cache_wait_event_unsafe(struct rrdeng_page_descr *descr) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + ++pg_cache_descr->waiters; + uv_cond_wait(&pg_cache_descr->cond, &pg_cache_descr->mutex); + --pg_cache_descr->waiters; +} + +/* + * The caller must hold page descriptor lock. + * The lock will be released and re-acquired. The descriptor is not guaranteed + * to exist after this function returns. + * Returns UV_ETIMEDOUT if timeout_sec seconds pass. + */ +int pg_cache_timedwait_event_unsafe(struct rrdeng_page_descr *descr, uint64_t timeout_sec) +{ + int ret; + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + ++pg_cache_descr->waiters; + ret = uv_cond_timedwait(&pg_cache_descr->cond, &pg_cache_descr->mutex, timeout_sec * NSEC_PER_SEC); + --pg_cache_descr->waiters; + + return ret; +} + +/* + * Returns page flags. + * The lock will be released and re-acquired. The descriptor is not guaranteed + * to exist after this function returns. + */ +unsigned long pg_cache_wait_event(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + unsigned long flags; + + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_wait_event_unsafe(descr); + flags = pg_cache_descr->flags; + rrdeng_page_descr_mutex_unlock(ctx, descr); + + return flags; +} + +/* + * The caller must hold page descriptor lock. + */ +int pg_cache_can_get_unsafe(struct rrdeng_page_descr *descr, int exclusive_access) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + if ((pg_cache_descr->flags & (RRD_PAGE_LOCKED | RRD_PAGE_READ_PENDING)) || + (exclusive_access && pg_cache_descr->refcnt)) { + return 0; + } + + return 1; +} + +/* + * The caller must hold page descriptor lock. + * Gets a reference to the page descriptor. + * Returns 1 on success and 0 on failure. + */ +int pg_cache_try_get_unsafe(struct rrdeng_page_descr *descr, int exclusive_access) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + if (!pg_cache_can_get_unsafe(descr, exclusive_access)) + return 0; + + if (exclusive_access) + pg_cache_descr->flags |= RRD_PAGE_LOCKED; + ++pg_cache_descr->refcnt; + + return 1; +} + +/* + * The caller must hold the page descriptor lock. + * This function may block doing cleanup. + */ +void pg_cache_put_unsafe(struct rrdeng_page_descr *descr) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + pg_cache_descr->flags &= ~RRD_PAGE_LOCKED; + if (0 == --pg_cache_descr->refcnt) { + pg_cache_wake_up_waiters_unsafe(descr); + } +} + +/* + * This function may block doing cleanup. + */ +void pg_cache_put(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr) +{ + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_put_unsafe(descr); + rrdeng_page_descr_mutex_unlock(ctx, descr); +} + +/* The caller must hold the page cache lock */ +static void pg_cache_release_pages_unsafe(struct rrdengine_instance *ctx, unsigned number) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + pg_cache->populated_pages -= number; +} + +static void pg_cache_release_pages(struct rrdengine_instance *ctx, unsigned number) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + pg_cache_release_pages_unsafe(ctx, number); + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); +} + +/* + * This function returns the maximum number of pages allowed in the page cache. + */ +unsigned long pg_cache_hard_limit(struct rrdengine_instance *ctx) +{ + /* it's twice the number of producers since we pin 2 pages per producer */ + return ctx->max_cache_pages + 2 * (unsigned long)ctx->metric_API_max_producers; +} + +/* + * This function returns the low watermark number of pages in the page cache. The page cache should strive to keep the + * number of pages below that number. + */ +unsigned long pg_cache_soft_limit(struct rrdengine_instance *ctx) +{ + /* it's twice the number of producers since we pin 2 pages per producer */ + return ctx->cache_pages_low_watermark + 2 * (unsigned long)ctx->metric_API_max_producers; +} + +/* + * This function returns the maximum number of dirty pages that are committed to be written to disk allowed in the page + * cache. + */ +unsigned long pg_cache_committed_hard_limit(struct rrdengine_instance *ctx) +{ + /* We remove the active pages of the producers from the calculation and only allow the extra pinned pages */ + return ctx->cache_pages_low_watermark + (unsigned long)ctx->metric_API_max_producers; +} + +/* + * This function will block until it reserves #number populated pages. + * It will trigger evictions or dirty page flushing if the pg_cache_hard_limit() limit is hit. + */ +static void pg_cache_reserve_pages(struct rrdengine_instance *ctx, unsigned number) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + unsigned failures = 0; + const unsigned FAILURES_CEILING = 10; /* truncates exponential backoff to (2^FAILURES_CEILING x slot) */ + unsigned long exp_backoff_slot_usec = USEC_PER_MS * 10; + + assert(number < ctx->max_cache_pages); + + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + if (pg_cache->populated_pages + number >= pg_cache_hard_limit(ctx) + 1) + debug(D_RRDENGINE, "==Page cache full. Reserving %u pages.==", + number); + while (pg_cache->populated_pages + number >= pg_cache_hard_limit(ctx) + 1) { + + if (!pg_cache_try_evict_one_page_unsafe(ctx)) { + /* failed to evict */ + struct completion compl; + struct rrdeng_cmd cmd; + + ++failures; + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); + + init_completion(&compl); + cmd.opcode = RRDENG_FLUSH_PAGES; + cmd.completion = &compl; + rrdeng_enq_cmd(&ctx->worker_config, &cmd); + /* wait for some pages to be flushed */ + debug(D_RRDENGINE, "%s: waiting for pages to be written to disk before evicting.", __func__); + wait_for_completion(&compl); + destroy_completion(&compl); + + if (unlikely(failures > 1)) { + unsigned long slots; + /* exponential backoff */ + slots = random() % (2LU << MIN(failures, FAILURES_CEILING)); + (void)sleep_usec(slots * exp_backoff_slot_usec); + } + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + } + } + pg_cache->populated_pages += number; + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); +} + +/* + * This function will attempt to reserve #number populated pages. + * It may trigger evictions if the pg_cache_soft_limit() limit is hit. + * Returns 0 on failure and 1 on success. + */ +static int pg_cache_try_reserve_pages(struct rrdengine_instance *ctx, unsigned number) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + unsigned count = 0; + int ret = 0; + + assert(number < ctx->max_cache_pages); + + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + if (pg_cache->populated_pages + number >= pg_cache_soft_limit(ctx) + 1) { + debug(D_RRDENGINE, + "==Page cache full. Trying to reserve %u pages.==", + number); + do { + if (!pg_cache_try_evict_one_page_unsafe(ctx)) + break; + ++count; + } while (pg_cache->populated_pages + number >= pg_cache_soft_limit(ctx) + 1); + debug(D_RRDENGINE, "Evicted %u pages.", count); + } + + if (pg_cache->populated_pages + number < pg_cache_hard_limit(ctx) + 1) { + pg_cache->populated_pages += number; + ret = 1; /* success */ + } + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); + + return ret; +} + +/* The caller must hold the page cache and the page descriptor locks in that order */ +static void pg_cache_evict_unsafe(struct rrdengine_instance *ctx, struct rrdeng_page_descr *descr) +{ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + freez(pg_cache_descr->page); + pg_cache_descr->page = NULL; + pg_cache_descr->flags &= ~RRD_PAGE_POPULATED; + pg_cache_release_pages_unsafe(ctx, 1); + ++ctx->stats.pg_cache_evictions; +} + +/* + * The caller must hold the page cache lock. + * Lock order: page cache -> replaceQ -> page descriptor + * This function iterates all pages and tries to evict one. + * If it fails it sets in_flight_descr to the oldest descriptor that has write-back in progress, + * or it sets it to NULL if no write-back is in progress. + * + * Returns 1 on success and 0 on failure. + */ +static int pg_cache_try_evict_one_page_unsafe(struct rrdengine_instance *ctx) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + unsigned long old_flags; + struct rrdeng_page_descr *descr; + struct page_cache_descr *pg_cache_descr = NULL; + + uv_rwlock_wrlock(&pg_cache->replaceQ.lock); + for (pg_cache_descr = pg_cache->replaceQ.head ; NULL != pg_cache_descr ; pg_cache_descr = pg_cache_descr->next) { + descr = pg_cache_descr->descr; + + rrdeng_page_descr_mutex_lock(ctx, descr); + old_flags = pg_cache_descr->flags; + if ((old_flags & RRD_PAGE_POPULATED) && !(old_flags & RRD_PAGE_DIRTY) && pg_cache_try_get_unsafe(descr, 1)) { + /* must evict */ + pg_cache_evict_unsafe(ctx, descr); + pg_cache_put_unsafe(descr); + pg_cache_replaceQ_delete_unsafe(ctx, descr); + + rrdeng_page_descr_mutex_unlock(ctx, descr); + uv_rwlock_wrunlock(&pg_cache->replaceQ.lock); + + rrdeng_try_deallocate_pg_cache_descr(ctx, descr); + + return 1; + } + rrdeng_page_descr_mutex_unlock(ctx, descr); + } + uv_rwlock_wrunlock(&pg_cache->replaceQ.lock); + + /* failed to evict */ + return 0; +} + +/** + * Deletes a page from the database. + * Callers of this function need to make sure they're not deleting the same descriptor concurrently. + * @param ctx is the database instance. + * @param descr is the page descriptor. + * @param remove_dirty must be non-zero if the page to be deleted is dirty. + * @param is_exclusive_holder must be non-zero if the caller holds an exclusive page reference. + * @param metric_id is set to the metric the page belongs to, if it's safe to delete the metric and metric_id is not + * NULL. Otherwise, metric_id is not set. + * @return 1 if it's safe to delete the metric, 0 otherwise. + */ +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) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct page_cache_descr *pg_cache_descr = NULL; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index = NULL; + int ret; + uint8_t can_delete_metric = 0; + + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, descr->id, sizeof(uuid_t)); + fatal_assert(NULL != PValue); + page_index = *PValue; + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + + uv_rwlock_wrlock(&page_index->lock); + ret = JudyLDel(&page_index->JudyL_array, (Word_t)(descr->start_time / USEC_PER_SEC), PJE0); + if (unlikely(0 == ret)) { + uv_rwlock_wrunlock(&page_index->lock); + error("Page under deletion was not in index."); + if (unlikely(debug_flags & D_RRDENGINE)) { + print_page_descr(descr); + } + goto destroy; + } + --page_index->page_count; + if (!page_index->writers && !page_index->page_count) { + can_delete_metric = 1; + if (metric_id) { + memcpy(metric_id, page_index->id, sizeof(uuid_t)); + } + } + uv_rwlock_wrunlock(&page_index->lock); + fatal_assert(1 == ret); + + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + ++ctx->stats.pg_cache_deletions; + --pg_cache->page_descriptors; + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); + + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_descr = descr->pg_cache_descr; + if (!is_exclusive_holder) { + /* If we don't hold an exclusive page reference get one */ + while (!pg_cache_try_get_unsafe(descr, 1)) { + debug(D_RRDENGINE, "%s: Waiting for locked page:", __func__); + if (unlikely(debug_flags & D_RRDENGINE)) + print_page_cache_descr(descr); + pg_cache_wait_event_unsafe(descr); + } + } + if (remove_dirty) { + pg_cache_descr->flags &= ~RRD_PAGE_DIRTY; + } else { + /* even a locked page could be dirty */ + while (unlikely(pg_cache_descr->flags & RRD_PAGE_DIRTY)) { + debug(D_RRDENGINE, "%s: Found dirty page, waiting for it to be flushed:", __func__); + if (unlikely(debug_flags & D_RRDENGINE)) + print_page_cache_descr(descr); + pg_cache_wait_event_unsafe(descr); + } + } + rrdeng_page_descr_mutex_unlock(ctx, descr); + + if (pg_cache_descr->flags & RRD_PAGE_POPULATED) { + /* only after locking can it be safely deleted from LRU */ + pg_cache_replaceQ_delete(ctx, descr); + + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + pg_cache_evict_unsafe(ctx, descr); + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); + } + pg_cache_put(ctx, descr); + rrdeng_try_deallocate_pg_cache_descr(ctx, descr); + while (descr->pg_cache_descr_state & PG_CACHE_DESCR_ALLOCATED) { + rrdeng_try_deallocate_pg_cache_descr(ctx, descr); /* spin */ + (void)sleep_usec(1000); /* 1 msec */ + } +destroy: + freez(descr); + pg_cache_update_metric_times(page_index); + + return can_delete_metric; +} + +static inline int is_page_in_time_range(struct rrdeng_page_descr *descr, usec_t start_time, usec_t end_time) +{ + usec_t pg_start, pg_end; + + pg_start = descr->start_time; + pg_end = descr->end_time; + + return (pg_start < start_time && pg_end >= start_time) || + (pg_start >= start_time && pg_start <= end_time); +} + +static inline int is_point_in_time_in_page(struct rrdeng_page_descr *descr, usec_t point_in_time) +{ + return (point_in_time >= descr->start_time && point_in_time <= descr->end_time); +} + +/* The caller must hold the page index lock */ +static inline struct rrdeng_page_descr * + find_first_page_in_time_range(struct pg_cache_page_index *page_index, usec_t start_time, usec_t end_time) +{ + struct rrdeng_page_descr *descr = NULL; + Pvoid_t *PValue; + Word_t Index; + + Index = (Word_t)(start_time / USEC_PER_SEC); + PValue = JudyLLast(page_index->JudyL_array, &Index, PJE0); + if (likely(NULL != PValue)) { + descr = *PValue; + if (is_page_in_time_range(descr, start_time, end_time)) { + return descr; + } + } + + Index = (Word_t)(start_time / USEC_PER_SEC); + PValue = JudyLFirst(page_index->JudyL_array, &Index, PJE0); + if (likely(NULL != PValue)) { + descr = *PValue; + if (is_page_in_time_range(descr, start_time, end_time)) { + return descr; + } + } + + return NULL; +} + +/* Update metric oldest and latest timestamps efficiently when adding new values */ +void pg_cache_add_new_metric_time(struct pg_cache_page_index *page_index, struct rrdeng_page_descr *descr) +{ + usec_t oldest_time = page_index->oldest_time; + usec_t latest_time = page_index->latest_time; + + if (unlikely(oldest_time == INVALID_TIME || descr->start_time < oldest_time)) { + page_index->oldest_time = descr->start_time; + } + if (likely(descr->end_time > latest_time || latest_time == INVALID_TIME)) { + page_index->latest_time = descr->end_time; + } +} + +/* Update metric oldest and latest timestamps when removing old values */ +void pg_cache_update_metric_times(struct pg_cache_page_index *page_index) +{ + Pvoid_t *firstPValue, *lastPValue; + Word_t firstIndex, lastIndex; + struct rrdeng_page_descr *descr; + usec_t oldest_time = INVALID_TIME; + usec_t latest_time = INVALID_TIME; + + uv_rwlock_rdlock(&page_index->lock); + /* Find first page in range */ + firstIndex = (Word_t)0; + firstPValue = JudyLFirst(page_index->JudyL_array, &firstIndex, PJE0); + if (likely(NULL != firstPValue)) { + descr = *firstPValue; + oldest_time = descr->start_time; + } + lastIndex = (Word_t)-1; + lastPValue = JudyLLast(page_index->JudyL_array, &lastIndex, PJE0); + if (likely(NULL != lastPValue)) { + descr = *lastPValue; + latest_time = descr->end_time; + } + uv_rwlock_rdunlock(&page_index->lock); + + if (unlikely(NULL == firstPValue)) { + fatal_assert(NULL == lastPValue); + page_index->oldest_time = page_index->latest_time = INVALID_TIME; + return; + } + page_index->oldest_time = oldest_time; + page_index->latest_time = latest_time; +} + +/* If index is NULL lookup by UUID (descr->id) */ +void pg_cache_insert(struct rrdengine_instance *ctx, struct pg_cache_page_index *index, + struct rrdeng_page_descr *descr) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index; + unsigned long pg_cache_descr_state = descr->pg_cache_descr_state; + + if (0 != pg_cache_descr_state) { + /* there is page cache descriptor pre-allocated state */ + struct page_cache_descr *pg_cache_descr = descr->pg_cache_descr; + + fatal_assert(pg_cache_descr_state & PG_CACHE_DESCR_ALLOCATED); + if (pg_cache_descr->flags & RRD_PAGE_POPULATED) { + pg_cache_reserve_pages(ctx, 1); + if (!(pg_cache_descr->flags & RRD_PAGE_DIRTY)) + pg_cache_replaceQ_insert(ctx, descr); + } + } + + if (unlikely(NULL == index)) { + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, descr->id, sizeof(uuid_t)); + fatal_assert(NULL != PValue); + page_index = *PValue; + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + } else { + page_index = index; + } + + uv_rwlock_wrlock(&page_index->lock); + PValue = JudyLIns(&page_index->JudyL_array, (Word_t)(descr->start_time / USEC_PER_SEC), PJE0); + *PValue = descr; + ++page_index->page_count; + pg_cache_add_new_metric_time(page_index, descr); + uv_rwlock_wrunlock(&page_index->lock); + + uv_rwlock_wrlock(&pg_cache->pg_cache_rwlock); + ++ctx->stats.pg_cache_insertions; + ++pg_cache->page_descriptors; + uv_rwlock_wrunlock(&pg_cache->pg_cache_rwlock); +} + +usec_t pg_cache_oldest_time_in_range(struct rrdengine_instance *ctx, uuid_t *id, usec_t start_time, usec_t end_time) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct rrdeng_page_descr *descr = NULL; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index = NULL; + + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, id, sizeof(uuid_t)); + if (likely(NULL != PValue)) { + page_index = *PValue; + } + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + if (NULL == PValue) { + return INVALID_TIME; + } + + uv_rwlock_rdlock(&page_index->lock); + descr = find_first_page_in_time_range(page_index, start_time, end_time); + if (NULL == descr) { + uv_rwlock_rdunlock(&page_index->lock); + return INVALID_TIME; + } + uv_rwlock_rdunlock(&page_index->lock); + return descr->start_time; +} + +/** + * Return page information for the first page before point_in_time that satisfies the filter. + * @param ctx DB context + * @param page_index page index of a metric + * @param point_in_time the pages that are searched must be older than this timestamp + * @param filter decides if the page satisfies the caller's criteria + * @param page_info the result of the search is set in this pointer + */ +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) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct rrdeng_page_descr *descr = NULL; + Pvoid_t *PValue; + Word_t Index; + + (void)pg_cache; + fatal_assert(NULL != page_index); + + Index = (Word_t)(point_in_time / USEC_PER_SEC); + uv_rwlock_rdlock(&page_index->lock); + do { + PValue = JudyLPrev(page_index->JudyL_array, &Index, PJE0); + descr = unlikely(NULL == PValue) ? NULL : *PValue; + } while (descr != NULL && !filter(descr)); + if (unlikely(NULL == descr)) { + page_info->page_length = 0; + page_info->start_time = INVALID_TIME; + page_info->end_time = INVALID_TIME; + } else { + page_info->page_length = descr->page_length; + page_info->start_time = descr->start_time; + page_info->end_time = descr->end_time; + } + uv_rwlock_rdunlock(&page_index->lock); +} +/** + * Searches for pages in a time range and triggers disk I/O if necessary and possible. + * Does not get a reference. + * @param ctx DB context + * @param id UUID + * @param start_time inclusive starting time in usec + * @param end_time inclusive ending time in usec + * @param page_info_arrayp It allocates (*page_arrayp) and populates it with information of pages that overlap + * with the time range [start_time,end_time]. The caller must free (*page_info_arrayp) with freez(). + * If page_info_arrayp is set to NULL nothing was allocated. + * @param ret_page_indexp Sets the page index pointer (*ret_page_indexp) for the given UUID. + * @return the number of pages that overlap with the time range [start_time,end_time]. + */ +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) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct rrdeng_page_descr *descr = NULL, *preload_array[PAGE_CACHE_MAX_PRELOAD_PAGES]; + struct page_cache_descr *pg_cache_descr = NULL; + unsigned i, j, k, preload_count, count, page_info_array_max_size; + unsigned long flags; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index = NULL; + Word_t Index; + uint8_t failed_to_reserve; + + fatal_assert(NULL != ret_page_indexp); + + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, id, sizeof(uuid_t)); + if (likely(NULL != PValue)) { + *ret_page_indexp = page_index = *PValue; + } + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + if (NULL == PValue) { + debug(D_RRDENGINE, "%s: No page was found to attempt preload.", __func__); + *ret_page_indexp = NULL; + return 0; + } + + uv_rwlock_rdlock(&page_index->lock); + descr = find_first_page_in_time_range(page_index, start_time, end_time); + if (NULL == descr) { + uv_rwlock_rdunlock(&page_index->lock); + debug(D_RRDENGINE, "%s: No page was found to attempt preload.", __func__); + *ret_page_indexp = NULL; + return 0; + } else { + Index = (Word_t)(descr->start_time / USEC_PER_SEC); + } + if (page_info_arrayp) { + page_info_array_max_size = PAGE_CACHE_MAX_PRELOAD_PAGES * sizeof(struct rrdeng_page_info); + *page_info_arrayp = mallocz(page_info_array_max_size); + } + + for (count = 0, preload_count = 0 ; + descr != NULL && is_page_in_time_range(descr, start_time, end_time) ; + PValue = JudyLNext(page_index->JudyL_array, &Index, PJE0), + descr = unlikely(NULL == PValue) ? NULL : *PValue) { + /* Iterate all pages in range */ + + if (unlikely(0 == descr->page_length)) + continue; + if (page_info_arrayp) { + if (unlikely(count >= page_info_array_max_size / sizeof(struct rrdeng_page_info))) { + page_info_array_max_size += PAGE_CACHE_MAX_PRELOAD_PAGES * sizeof(struct rrdeng_page_info); + *page_info_arrayp = reallocz(*page_info_arrayp, page_info_array_max_size); + } + (*page_info_arrayp)[count].start_time = descr->start_time; + (*page_info_arrayp)[count].end_time = descr->end_time; + (*page_info_arrayp)[count].page_length = descr->page_length; + } + ++count; + + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_descr = descr->pg_cache_descr; + flags = pg_cache_descr->flags; + if (pg_cache_can_get_unsafe(descr, 0)) { + if (flags & RRD_PAGE_POPULATED) { + /* success */ + rrdeng_page_descr_mutex_unlock(ctx, descr); + debug(D_RRDENGINE, "%s: Page was found in memory.", __func__); + continue; + } + } + if (!(flags & RRD_PAGE_POPULATED) && pg_cache_try_get_unsafe(descr, 1)) { + preload_array[preload_count++] = descr; + if (PAGE_CACHE_MAX_PRELOAD_PAGES == preload_count) { + rrdeng_page_descr_mutex_unlock(ctx, descr); + break; + } + } + rrdeng_page_descr_mutex_unlock(ctx, descr); + + } + uv_rwlock_rdunlock(&page_index->lock); + + failed_to_reserve = 0; + for (i = 0 ; i < preload_count && !failed_to_reserve ; ++i) { + struct rrdeng_cmd cmd; + struct rrdeng_page_descr *next; + + descr = preload_array[i]; + if (NULL == descr) { + continue; + } + if (!pg_cache_try_reserve_pages(ctx, 1)) { + failed_to_reserve = 1; + break; + } + cmd.opcode = RRDENG_READ_EXTENT; + cmd.read_extent.page_cache_descr[0] = descr; + /* don't use this page again */ + preload_array[i] = NULL; + for (j = 0, k = 1 ; j < preload_count ; ++j) { + next = preload_array[j]; + if (NULL == next) { + continue; + } + if (descr->extent == next->extent) { + /* same extent, consolidate */ + if (!pg_cache_try_reserve_pages(ctx, 1)) { + failed_to_reserve = 1; + break; + } + cmd.read_extent.page_cache_descr[k++] = next; + /* don't use this page again */ + preload_array[j] = NULL; + } + } + cmd.read_extent.page_count = k; + rrdeng_enq_cmd(&ctx->worker_config, &cmd); + } + if (failed_to_reserve) { + debug(D_RRDENGINE, "%s: Failed to reserve enough memory, canceling I/O.", __func__); + for (i = 0 ; i < preload_count ; ++i) { + descr = preload_array[i]; + if (NULL == descr) { + continue; + } + pg_cache_put(ctx, descr); + } + } + if (!preload_count) { + /* no such page */ + debug(D_RRDENGINE, "%s: No page was eligible to attempt preload.", __func__); + } + if (unlikely(0 == count && page_info_arrayp)) { + freez(*page_info_arrayp); + *page_info_arrayp = NULL; + } + return count; +} + +/* + * Searches for a page and gets a reference. + * When point_in_time is INVALID_TIME get any page. + * If index is NULL lookup by UUID (id). + */ +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) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct rrdeng_page_descr *descr = NULL; + struct page_cache_descr *pg_cache_descr = NULL; + unsigned long flags; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index = NULL; + Word_t Index; + uint8_t page_not_in_cache; + + if (unlikely(NULL == index)) { + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, id, sizeof(uuid_t)); + if (likely(NULL != PValue)) { + page_index = *PValue; + } + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + if (NULL == PValue) { + return NULL; + } + } else { + page_index = index; + } + pg_cache_reserve_pages(ctx, 1); + + page_not_in_cache = 0; + uv_rwlock_rdlock(&page_index->lock); + while (1) { + Index = (Word_t)(point_in_time / USEC_PER_SEC); + PValue = JudyLLast(page_index->JudyL_array, &Index, PJE0); + if (likely(NULL != PValue)) { + descr = *PValue; + } + if (NULL == PValue || + 0 == descr->page_length || + (INVALID_TIME != point_in_time && + !is_point_in_time_in_page(descr, point_in_time))) { + /* non-empty page not found */ + uv_rwlock_rdunlock(&page_index->lock); + + pg_cache_release_pages(ctx, 1); + return NULL; + } + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_descr = descr->pg_cache_descr; + flags = pg_cache_descr->flags; + if ((flags & RRD_PAGE_POPULATED) && pg_cache_try_get_unsafe(descr, 0)) { + /* success */ + rrdeng_page_descr_mutex_unlock(ctx, descr); + debug(D_RRDENGINE, "%s: Page was found in memory.", __func__); + break; + } + if (!(flags & RRD_PAGE_POPULATED) && pg_cache_try_get_unsafe(descr, 1)) { + struct rrdeng_cmd cmd; + + uv_rwlock_rdunlock(&page_index->lock); + + cmd.opcode = RRDENG_READ_PAGE; + cmd.read_page.page_cache_descr = descr; + rrdeng_enq_cmd(&ctx->worker_config, &cmd); + + debug(D_RRDENGINE, "%s: Waiting for page to be asynchronously read from disk:", __func__); + if(unlikely(debug_flags & D_RRDENGINE)) + print_page_cache_descr(descr); + while (!(pg_cache_descr->flags & RRD_PAGE_POPULATED)) { + pg_cache_wait_event_unsafe(descr); + } + /* success */ + /* Downgrade exclusive reference to allow other readers */ + pg_cache_descr->flags &= ~RRD_PAGE_LOCKED; + pg_cache_wake_up_waiters_unsafe(descr); + rrdeng_page_descr_mutex_unlock(ctx, descr); + rrd_stat_atomic_add(&ctx->stats.pg_cache_misses, 1); + return descr; + } + uv_rwlock_rdunlock(&page_index->lock); + debug(D_RRDENGINE, "%s: Waiting for page to be unlocked:", __func__); + if(unlikely(debug_flags & D_RRDENGINE)) + print_page_cache_descr(descr); + if (!(flags & RRD_PAGE_POPULATED)) + page_not_in_cache = 1; + pg_cache_wait_event_unsafe(descr); + rrdeng_page_descr_mutex_unlock(ctx, descr); + + /* reset scan to find again */ + uv_rwlock_rdlock(&page_index->lock); + } + uv_rwlock_rdunlock(&page_index->lock); + + if (!(flags & RRD_PAGE_DIRTY)) + pg_cache_replaceQ_set_hot(ctx, descr); + pg_cache_release_pages(ctx, 1); + if (page_not_in_cache) + rrd_stat_atomic_add(&ctx->stats.pg_cache_misses, 1); + else + rrd_stat_atomic_add(&ctx->stats.pg_cache_hits, 1); + return descr; +} + +/* + * Searches for the first page between start_time and end_time and gets a reference. + * start_time and end_time are inclusive. + * If index is NULL lookup by UUID (id). + */ +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) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + struct rrdeng_page_descr *descr = NULL; + struct page_cache_descr *pg_cache_descr = NULL; + unsigned long flags; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index = NULL; + uint8_t page_not_in_cache; + + if (unlikely(NULL == index)) { + uv_rwlock_rdlock(&pg_cache->metrics_index.lock); + PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, id, sizeof(uuid_t)); + if (likely(NULL != PValue)) { + page_index = *PValue; + } + uv_rwlock_rdunlock(&pg_cache->metrics_index.lock); + if (NULL == PValue) { + return NULL; + } + } else { + page_index = index; + } + pg_cache_reserve_pages(ctx, 1); + + page_not_in_cache = 0; + uv_rwlock_rdlock(&page_index->lock); + while (1) { + descr = find_first_page_in_time_range(page_index, start_time, end_time); + if (NULL == descr || 0 == descr->page_length) { + /* non-empty page not found */ + uv_rwlock_rdunlock(&page_index->lock); + + pg_cache_release_pages(ctx, 1); + return NULL; + } + rrdeng_page_descr_mutex_lock(ctx, descr); + pg_cache_descr = descr->pg_cache_descr; + flags = pg_cache_descr->flags; + if ((flags & RRD_PAGE_POPULATED) && pg_cache_try_get_unsafe(descr, 0)) { + /* success */ + rrdeng_page_descr_mutex_unlock(ctx, descr); + debug(D_RRDENGINE, "%s: Page was found in memory.", __func__); + break; + } + if (!(flags & RRD_PAGE_POPULATED) && pg_cache_try_get_unsafe(descr, 1)) { + struct rrdeng_cmd cmd; + + uv_rwlock_rdunlock(&page_index->lock); + + cmd.opcode = RRDENG_READ_PAGE; + cmd.read_page.page_cache_descr = descr; + rrdeng_enq_cmd(&ctx->worker_config, &cmd); + + debug(D_RRDENGINE, "%s: Waiting for page to be asynchronously read from disk:", __func__); + if(unlikely(debug_flags & D_RRDENGINE)) + print_page_cache_descr(descr); + while (!(pg_cache_descr->flags & RRD_PAGE_POPULATED)) { + pg_cache_wait_event_unsafe(descr); + } + /* success */ + /* Downgrade exclusive reference to allow other readers */ + pg_cache_descr->flags &= ~RRD_PAGE_LOCKED; + pg_cache_wake_up_waiters_unsafe(descr); + rrdeng_page_descr_mutex_unlock(ctx, descr); + rrd_stat_atomic_add(&ctx->stats.pg_cache_misses, 1); + return descr; + } + uv_rwlock_rdunlock(&page_index->lock); + debug(D_RRDENGINE, "%s: Waiting for page to be unlocked:", __func__); + if(unlikely(debug_flags & D_RRDENGINE)) + print_page_cache_descr(descr); + if (!(flags & RRD_PAGE_POPULATED)) + page_not_in_cache = 1; + pg_cache_wait_event_unsafe(descr); + rrdeng_page_descr_mutex_unlock(ctx, descr); + + /* reset scan to find again */ + uv_rwlock_rdlock(&page_index->lock); + } + uv_rwlock_rdunlock(&page_index->lock); + + if (!(flags & RRD_PAGE_DIRTY)) + pg_cache_replaceQ_set_hot(ctx, descr); + pg_cache_release_pages(ctx, 1); + if (page_not_in_cache) + rrd_stat_atomic_add(&ctx->stats.pg_cache_misses, 1); + else + rrd_stat_atomic_add(&ctx->stats.pg_cache_hits, 1); + return descr; +} + +struct pg_cache_page_index *create_page_index(uuid_t *id) +{ + struct pg_cache_page_index *page_index; + + page_index = mallocz(sizeof(*page_index)); + page_index->JudyL_array = (Pvoid_t) NULL; + uuid_copy(page_index->id, *id); + fatal_assert(0 == uv_rwlock_init(&page_index->lock)); + page_index->oldest_time = INVALID_TIME; + page_index->latest_time = INVALID_TIME; + page_index->prev = NULL; + page_index->page_count = 0; + page_index->writers = 0; + + return page_index; +} + +static void init_metrics_index(struct rrdengine_instance *ctx) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + pg_cache->metrics_index.JudyHS_array = (Pvoid_t) NULL; + pg_cache->metrics_index.last_page_index = NULL; + fatal_assert(0 == uv_rwlock_init(&pg_cache->metrics_index.lock)); +} + +static void init_replaceQ(struct rrdengine_instance *ctx) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + pg_cache->replaceQ.head = NULL; + pg_cache->replaceQ.tail = NULL; + fatal_assert(0 == uv_rwlock_init(&pg_cache->replaceQ.lock)); +} + +static void init_committed_page_index(struct rrdengine_instance *ctx) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + pg_cache->committed_page_index.JudyL_array = (Pvoid_t) NULL; + fatal_assert(0 == uv_rwlock_init(&pg_cache->committed_page_index.lock)); + pg_cache->committed_page_index.latest_corr_id = 0; + pg_cache->committed_page_index.nr_committed_pages = 0; +} + +void init_page_cache(struct rrdengine_instance *ctx) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + + pg_cache->page_descriptors = 0; + pg_cache->populated_pages = 0; + fatal_assert(0 == uv_rwlock_init(&pg_cache->pg_cache_rwlock)); + + init_metrics_index(ctx); + init_replaceQ(ctx); + init_committed_page_index(ctx); +} + +void free_page_cache(struct rrdengine_instance *ctx) +{ + struct page_cache *pg_cache = &ctx->pg_cache; + Word_t ret_Judy, bytes_freed = 0; + Pvoid_t *PValue; + struct pg_cache_page_index *page_index, *prev_page_index; + Word_t Index; + struct rrdeng_page_descr *descr; + struct page_cache_descr *pg_cache_descr; + + /* Free committed page index */ + ret_Judy = JudyLFreeArray(&pg_cache->committed_page_index.JudyL_array, PJE0); + fatal_assert(NULL == pg_cache->committed_page_index.JudyL_array); + bytes_freed += ret_Judy; + + for (page_index = pg_cache->metrics_index.last_page_index ; + page_index != NULL ; + page_index = prev_page_index) { + prev_page_index = page_index->prev; + + /* Find first page in range */ + Index = (Word_t) 0; + PValue = JudyLFirst(page_index->JudyL_array, &Index, PJE0); + descr = unlikely(NULL == PValue) ? NULL : *PValue; + + while (descr != NULL) { + /* Iterate all page descriptors of this metric */ + + if (descr->pg_cache_descr_state & PG_CACHE_DESCR_ALLOCATED) { + /* Check rrdenglocking.c */ + pg_cache_descr = descr->pg_cache_descr; + if (pg_cache_descr->flags & RRD_PAGE_POPULATED) { + freez(pg_cache_descr->page); + bytes_freed += RRDENG_BLOCK_SIZE; + } + rrdeng_destroy_pg_cache_descr(ctx, pg_cache_descr); + bytes_freed += sizeof(*pg_cache_descr); + } + freez(descr); + bytes_freed += sizeof(*descr); + + PValue = JudyLNext(page_index->JudyL_array, &Index, PJE0); + descr = unlikely(NULL == PValue) ? NULL : *PValue; + } + + /* Free page index */ + ret_Judy = JudyLFreeArray(&page_index->JudyL_array, PJE0); + fatal_assert(NULL == page_index->JudyL_array); + bytes_freed += ret_Judy; + freez(page_index); + bytes_freed += sizeof(*page_index); + } + /* Free metrics index */ + ret_Judy = JudyHSFreeArray(&pg_cache->metrics_index.JudyHS_array, PJE0); + fatal_assert(NULL == pg_cache->metrics_index.JudyHS_array); + bytes_freed += ret_Judy; + + info("Freed %lu bytes of memory from page cache.", bytes_freed); +}
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