Core Cache

Core Cache Constants

EVACUATION_SIZE

The size of the contiguous area to check for evacuation.

Core Cache Types

type span_diskid_t

Stores a 16 byte ID.

class CacheKey

The hash value for a cache object. Currently a 128 bit MD5 hash.

class EvacuationBlock

A range of content to be evacuated.

class CacheProcessor

The singleton cache management object. This handles threads and global initialization for the cache.

• int start(int n_threads, size_t stacksize)

  Starts the cache processing threads, n_threads are created each with a stack of size stacksize.

class Span

Span models a cache span. This is a contiguous span of storage.

• int64_t blocks

  Number of storage blocks in the span. See STORE_BLOCK_SIZE.

• int64_t offset

  Offset (in bytes)_ to the start of the span. This is used only if the base storage is a file.

• span_diskid_t disk_id

  No idea what this is.

class Store

A singleton containing all of the cache storage description.

• unsigned n_disks_in_config

  The number of distinct devices in the configuration.

• unsigned n_disks

  The number of valid and distinct devices in the configuration.

• Span **disk

  List of spans.

• char *read_config()

  Read storage.config and initialize the base state of the instance. The return value is nullptr on success and a nul-terminated error string on error.

class CacheDisk

A representation of the physical device used for a Span.

Core Cache Functions

int dir_probe(const CacheKey *key, Vol *d, Dir *result, Dir **last_collision)

Probe the stripe directory for a candidate directory entry.

void build_vol_hash_table(CacheHostRecord *r)

Based on the configuration record r, construct the global stripe assignment table.

int cplist_reconfigure()

Rebuild the assignment of stripes to volumes.

void ink_cache_init(ModuleVersion v)

Top level cache initialization logic.