| 1 | /* |
| 2 | * Copyright (C) 2013 Julien Desfossez <jdesfossez@efficios.com> |
| 3 | * Copyright (C) 2013 David Goulet <dgoulet@efficios.com> |
| 4 | * |
| 5 | * SPDX-License-Identifier: GPL-2.0-only |
| 6 | * |
| 7 | */ |
| 8 | |
| 9 | #ifndef CONSUMER_METADATA_CACHE_H |
| 10 | #define CONSUMER_METADATA_CACHE_H |
| 11 | |
| 12 | #include <common/consumer/consumer.hpp> |
| 13 | #include <common/dynamic-buffer.hpp> |
| 14 | |
| 15 | enum consumer_metadata_cache_write_status { |
| 16 | CONSUMER_METADATA_CACHE_WRITE_STATUS_ERROR = -1, |
| 17 | /* |
| 18 | * New metadata content was appended to the cache successfully. |
| 19 | * Previously available content remains valid. |
| 20 | */ |
| 21 | CONSUMER_METADATA_CACHE_WRITE_STATUS_APPENDED_CONTENT = 0, |
| 22 | /* |
| 23 | * The new content pushed to the cache invalidated the content that |
| 24 | * was already present. The contents of the cache should be re-read. |
| 25 | */ |
| 26 | CONSUMER_METADATA_CACHE_WRITE_STATUS_INVALIDATED, |
| 27 | /* |
| 28 | * A metadata cache write can simply overwrite an already existing |
| 29 | * section of the cache (and it should be a write-through with identical |
| 30 | * data). From the caller's standpoint, there is no change to the state |
| 31 | * of the cache. |
| 32 | */ |
| 33 | CONSUMER_METADATA_CACHE_WRITE_STATUS_NO_CHANGE, |
| 34 | }; |
| 35 | |
| 36 | struct consumer_metadata_cache { |
| 37 | /* Current version of the metadata cache. */ |
| 38 | uint64_t version; |
| 39 | /* |
| 40 | * Size is the upper-limit of data written inside the buffer. |
| 41 | * All cached data is contiguous. |
| 42 | */ |
| 43 | struct lttng_dynamic_buffer contents; |
| 44 | /* |
| 45 | * Lock to update the metadata cache and push into the ring_buffer |
| 46 | * (lttng_ust_ctl_write_metadata_to_channel). |
| 47 | * |
| 48 | * This is nested INSIDE the consumer_data lock. |
| 49 | */ |
| 50 | pthread_mutex_t lock; |
| 51 | }; |
| 52 | |
| 53 | enum consumer_metadata_cache_write_status |
| 54 | consumer_metadata_cache_write(struct consumer_metadata_cache *cache, |
| 55 | unsigned int offset, |
| 56 | unsigned int len, |
| 57 | uint64_t version, |
| 58 | const char *data); |
| 59 | int consumer_metadata_cache_allocate(struct lttng_consumer_channel *channel); |
| 60 | void consumer_metadata_cache_destroy(struct lttng_consumer_channel *channel); |
| 61 | void consumer_wait_metadata_cache_flushed(struct lttng_consumer_channel *channel, |
| 62 | uint64_t offset, |
| 63 | bool invoked_by_timer); |
| 64 | |
| 65 | #endif /* CONSUMER_METADATA_CACHE_H */ |