net_instaweb::SharedMemCacheData::Sector< kBlockSize > Class Template Reference

#include "shared_mem_cache_data.h"

Public Member Functions
	Sector (AbstractSharedMemSegment *segment, size_t sector_offset, size_t cache_entries, size_t data_blocks)
bool	Attach (MessageHandler *handler)
bool	Initialize (MessageHandler *handler)
AbstractMutex *	mutex () const LOCK_RETURNED(mutex_)
	Mutex ops. More...
BlockNum	GetBlockSuccessor (BlockNum block) EXCLUSIVE_LOCKS_REQUIRED(mutex())
void	SetBlockSuccessor (BlockNum block, BlockNum next) EXCLUSIVE_LOCKS_REQUIRED(mutex())
void	LinkBlockSuccessors (const BlockVector &blocks) EXCLUSIVE_LOCKS_REQUIRED(mutex())
int	AllocBlocksFromFreeList (int goal, BlockVector *blocks) EXCLUSIVE_LOCKS_REQUIRED(mutex())
void	ReturnBlocksToFreeList (const BlockVector &blocks) EXCLUSIVE_LOCKS_REQUIRED(mutex())
CacheEntry *	EntryAt (EntryNum slot)
	Returns the given # entry. More...
void	InsertEntryIntoLRU (EntryNum entry_num)
void	UnlinkEntryFromLRU (EntryNum entry_num)
	Removes from the LRU. Safe to call if not in the LRU already.
EntryNum	OldestEntryNum ()
char *	BlockBytes (BlockNum block_num)
int	BlockListForEntry (CacheEntry *entry, BlockVector *out_blocks) EXCLUSIVE_LOCKS_REQUIRED(mutex())
SectorStats *	sector_stats ()
void	DumpStats (MessageHandler *handler)

Static Public Member Functions
static size_t	RequiredSize (AbstractSharedMem *shmem_runtime, size_t cache_entries, size_t data_blocks)
static size_t	DataBlocksForSize (size_t size)
	Number of blocks of data needed for size blocks. More...
static size_t	BytesInPortion (size_t total_bytes, size_t b, size_t total)

Detailed Description

template<size_t kBlockSize>
class net_instaweb::SharedMemCacheData::Sector< kBlockSize >

Helper for operating on a given sector's data structures; helping access them, lay them out in memory, and initialize them. It does not implement the actual cache operations, however. In particular, its methods affect only a single data structure at the time and do not do anything to preserve cross-structure invariants.

Constructor & Destructor Documentation

template<size_t kBlockSize>

net_instaweb::SharedMemCacheData::Sector< kBlockSize >::Sector	(	AbstractSharedMemSegment *	segment,
		size_t	sector_offset,
		size_t	cache_entries,
		size_t	data_blocks
	)

Creates a wrapper to help operate on cache sectors in a given region of memory with given geometry. The sector should have had as much memory allocated for it as returned by a call to RequiredSize with the same arguments.

Note that this doesn't do any imperative initialization; you must call Initialize() in the parent process, and Attach() in child processes, and check their results as well. Also, segment is assumed to be owned separately, with lifetime longer than ours.

Member Function Documentation

template<size_t kBlockSize>

int net_instaweb::SharedMemCacheData::Sector< kBlockSize >::AllocBlocksFromFreeList	(	int	goal,
		BlockVector *	blocks
	)

Freelist ops.Allocates as close to the goal blocks from freelist as it can, and appends their numbers to blocks. Returns how much it allocated. Does not adjust block successor lists.

Note that this doesn't attempt to free blocks that are in use by some entries.

template<size_t kBlockSize>

bool net_instaweb::SharedMemCacheData::Sector< kBlockSize >::Attach

(

MessageHandler *

handler

)

This should be called from child processes to initialize client state for the cache already formatted by a call to Initialize() in the parent.

Returns if successful (which it should be if the parent process successfully create the memory and Initialize()'d it).

template<size_t kBlockSize>

char* net_instaweb::SharedMemCacheData::Sector< kBlockSize >::BlockBytes ( BlockNum  block_num )

inline

Block ops.

template<size_t kBlockSize>

int net_instaweb::SharedMemCacheData::Sector< kBlockSize >::BlockListForEntry	(	CacheEntry *	entry,
		BlockVector *	out_blocks
	)

Appends the list of blocks used by the entry to 'blocks'. Returns the number of items appended.

template<size_t kBlockSize>

static size_t net_instaweb::SharedMemCacheData::Sector< kBlockSize >::BytesInPortion ( size_t  total_bytes, size_t  b, size_t  total  )

static

The # of bytes stored in block 'b' out of 'total' blocks for file of size 'total_bytes'. Precondition: 'total' is appropriate for 'total_bytes'.

template<size_t kBlockSize>

static size_t net_instaweb::SharedMemCacheData::Sector< kBlockSize >::DataBlocksForSize ( size_t  size )

inlinestatic

Number of blocks of data needed for size blocks.

Ops for lists of blocks corresponding to each directory entry, and related size computations

template<size_t kBlockSize>

void net_instaweb::SharedMemCacheData::Sector< kBlockSize >::DumpStats

(

MessageHandler *

handler

)

Prints out all statistics in the header (some of which are maintained by the higher-level)

template<size_t kBlockSize>

CacheEntry* net_instaweb::SharedMemCacheData::Sector< kBlockSize >::EntryAt ( EntryNum  slot )

inline

Returns the given # entry.

Cache directory ops.

template<size_t kBlockSize>

BlockNum net_instaweb::SharedMemCacheData::Sector< kBlockSize >::GetBlockSuccessor ( BlockNum  block )

inline

Block successor list ops.

template<size_t kBlockSize>

bool net_instaweb::SharedMemCacheData::Sector< kBlockSize >::Initialize

(

MessageHandler *

handler

)

This should be called from the initial/parent process before the children start. It initializes the data structures in this sector, including mutexes. Returns true on success.

template<size_t kBlockSize>

void net_instaweb::SharedMemCacheData::Sector< kBlockSize >::InsertEntryIntoLRU

(

EntryNum

entry_num

)

Inserts the given entry into the LRU, at front. Precondition: must not be in LRU.

template<size_t kBlockSize>

void net_instaweb::SharedMemCacheData::Sector< kBlockSize >::LinkBlockSuccessors ( const BlockVector &  blocks )

inline

Links blocks in the vector in order, with later blocks being marked as successors of later ones.

template<size_t kBlockSize>

AbstractMutex* net_instaweb::SharedMemCacheData::Sector< kBlockSize >::mutex ( ) const

inline

Mutex ops.

The sector lock should be held while doing any metadata accesses.

template<size_t kBlockSize>

static size_t net_instaweb::SharedMemCacheData::Sector< kBlockSize >::RequiredSize ( AbstractSharedMem *  shmem_runtime, size_t  cache_entries, size_t  data_blocks  )

static

Computes how much memory a sector will need for given number of entries. Also makes sure it's padded to proper alignment.

template<size_t kBlockSize>

void net_instaweb::SharedMemCacheData::Sector< kBlockSize >::ReturnBlocksToFreeList

(

const BlockVector &

blocks

)

Puts all the passed in blocks onto this sector's freelist. Does not read successors for passed in blocks, but does set them for freelist membership.

template<size_t kBlockSize>

SectorStats* net_instaweb::SharedMemCacheData::Sector< kBlockSize >::sector_stats ( )

inline

Statistics stuff

---

The documentation for this class was generated from the following file:

• pagespeed/kernel/sharedmem/shared_mem_cache_data.h