Attribute Cache (acache)

The acache implements a simple client side cache for PVFS2 attibutes as well as logical file sizes. More...

Files
file	acache.c
file	acache.h
Defines
#define	PINT_acache_options   PINT_tcache_options
Functions
void	PINT_acache_enable_perf_counter (struct PINT_perf_counter *pc, struct PINT_perf_counter *static_pc)
int	PINT_acache_initialize (void)
void	PINT_acache_finalize (void)
int	PINT_acache_get_info (enum PINT_acache_options option, unsigned int *arg)
int	PINT_acache_set_info (enum PINT_acache_options option, unsigned int arg)
int	PINT_acache_get_cached_entry (PVFS_object_ref refn, PVFS_object_attr *attr, int *attr_status, PVFS_size *size, int *size_status)
int	PINT_acache_update (PVFS_object_ref refn, PVFS_object_attr *attr, PVFS_size *size)
void	PINT_acache_invalidate (PVFS_object_ref refn)
void	PINT_acache_invalidate_size (PVFS_object_ref refn)
Variables
PINT_perf_key	acache_keys []
PINT_perf_key	acache_keys []

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Detailed Description

The acache implements a simple client side cache for PVFS2 attibutes as well as logical file sizes.

A timeout is associated with each attribute structure to dictate when it will expire, and the attribute mask is used to determine which fields in the attribute structure are valid at a given time. The acache is built on top of the generic tcache caching component.

The tcache implements a simple component for caching data structures that can be referenced by unique, opaque keys. A timeout is associated with each entry to dictate when it will expire. Specific caches such as the attribute or name cache may be built on top of this one.

Notes:

• See tcache for policy documentation
• Note that the acache never explicitly deletes an entry. Instead, it will invalidate an entry but leave it in the cache.

Operations that may retrieve items from acache:

• truncate
• symlink
• rename
• readdir
• mkdir
• lookup
• io
• getattr
• flush
• create
• remove
• mgmt-get-dfile-array
• setattrib

Operations that may insert items into the cache:

• create
• getattr
• setattr
• mkdir
• symlink

Operations that may invalidate items in the cache:

• remove
• rename
• io (size only)
• truncate (size only)
• any failed sysint operation from the list of operations that retrieve attributes

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Define Documentation

#define PINT_acache_options   PINT_tcache_options

See also: PINT_tcache_options

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Function Documentation

void PINT_acache_enable_perf_counter (  struct PINT_perf_counter *  pc, struct PINT_perf_counter *  static_pc )

Enables perf counter instrumentation of the acache. Parameters: pc  counter for non static fields static_pc  counter for static fields

void PINT_acache_finalize (  void   )

Finalizes and destroys the acache, frees all cached entries.

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int PINT_acache_get_cached_entry (  PVFS_object_ref  refn, PVFS_object_attr *  attr, int *  attr_status, PVFS_size *  size, int *  size_status )

Retrieves a _copy_ of a cached attributes structure. Also retrieves the logical file size (if the object in question is a file) and reports the status of both the attributes and size to indicate if they are valid or not Returns: 0 on success, -PVFS_error on failure Parameters: refn  PVFS2 object to look up attr  attributes of the object attr_status  indicates if the attributes are expired or not size  logical size of the object (only valid for files) size_status  indicates if the size has expired or not

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int PINT_acache_get_info (  enum PINT_acache_options  option, unsigned int *  arg )

Retrieves parameters from the acache. See also: PINT_tcache_options Returns: 0 on success, -PVFS_error on failure Parameters: option  option to read arg  output value

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int PINT_acache_initialize (  void   )

Initializes the acache. Returns: pointer to tcache on success, NULL on failure

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void PINT_acache_invalidate (  PVFS_object_ref  refn  )

Invalidates a cache entry (if present).

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void PINT_acache_invalidate_size (  PVFS_object_ref  refn  )

Invalidates only the logical size assocated with an entry (if present).

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int PINT_acache_set_info (  enum PINT_acache_options  option, unsigned int  arg )

Sets optional parameters in the acache. See also: PINT_tcache_options Returns: 0 on success, -PVFS_error on failure Parameters: option  option to modify arg  input value

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int PINT_acache_update (  PVFS_object_ref  refn, PVFS_object_attr *  attr, PVFS_size *  size )

Adds a set of attributes to the cache, or updates them if they are already present. The given attributes are _copied_ into the cache. Size parameter will not be updated if it is NULL. Note: NOTE: All previous attribute and size information for the object will be discarded, even if there is still time remaining before it expires and the new attributes and/or size contain less information. Returns: 0 on success, -PVFS_error on failure Parameters: refn  object to update attr  attributes to copy into cache size  logical file size (NULL if not available)

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Variable Documentation

struct PINT_perf_key acache_keys[]

acache performance counter keys

struct PINT_perf_key acache_keys[]

Initial value: { {"ACACHE_NUM_ENTRIES", PERF_ACACHE_NUM_ENTRIES, PINT_PERF_PRESERVE}, {"ACACHE_SOFT_LIMIT", PERF_ACACHE_SOFT_LIMIT, PINT_PERF_PRESERVE}, {"ACACHE_HARD_LIMIT", PERF_ACACHE_HARD_LIMIT, PINT_PERF_PRESERVE}, {"ACACHE_HITS", PERF_ACACHE_HITS, 0}, {"ACACHE_MISSES", PERF_ACACHE_MISSES, 0}, {"ACACHE_UPDATES", PERF_ACACHE_UPDATES, 0}, {"ACACHE_PURGES", PERF_ACACHE_PURGES, 0}, {"ACACHE_REPLACEMENTS", PERF_ACACHE_REPLACEMENTS, 0}, {"ACACHE_DELETIONS", PERF_ACACHE_DELETIONS, 0}, {"ACACHE_ENABLED", PERF_ACACHE_ENABLED, PINT_PERF_PRESERVE}, {NULL, 0, 0}, } acache performance counter keys

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