Name Cache (ncache)

The ncache implements a simple client side cache for PVFS2 files. More...

Files
file	ncache.c
file	ncache.h
Defines
#define	PINT_ncache_options   PINT_tcache_options
Functions
void	PINT_ncache_enable_perf_counter (struct PINT_perf_counter *pc)
int	PINT_ncache_initialize (void)
void	PINT_ncache_finalize (void)
int	PINT_ncache_get_info (enum PINT_ncache_options option, unsigned int *arg)
int	PINT_ncache_set_info (enum PINT_ncache_options option, unsigned int arg)
int	PINT_ncache_get_cached_entry (const char *entry, PVFS_object_ref *entry_ref, const PVFS_object_ref *parent_ref)
int	PINT_ncache_update (const char *entry, const PVFS_object_ref *entry_ref, const PVFS_object_ref *parent_ref)
void	PINT_ncache_invalidate (const char *entry, const PVFS_object_ref *parent_ref)
Variables
PINT_perf_key	ncache_keys []
PINT_perf_key	ncache_keys []

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Detailed Description

The ncache implements a simple client side cache for PVFS2 files.

A timeout is associated with each entry to dictate when it will expire. The ncache is built on top of the generic tcache caching component. The NCACHE component will cache the following:

• parent handle
• entry for a specific file OR directory within the parent directory
• entry handle

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

Operations that may retrieve items from ncache:

• lookup
• rename (Current implementation does not yet use ncache)

Operations that may insert items into the cache:

• pvfs2-lookup
• pvfs2-rename (Current implementation does not yet use ncache)
• pvfs2-symlink
• pvfs2-readdir
• pvfs2-mkdir
• pvfs2-create

Operations that may DELETE items from the cache:

• pvfs2-remove
• pvfs2-rename
• any failed sysint operation from the list of operations that retrieve items from NCACHE

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Define Documentation

#define PINT_ncache_options   PINT_tcache_options

See also: PINT_tcache_options

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Function Documentation

void PINT_ncache_enable_perf_counter (  struct PINT_perf_counter *  pc  )

Enables perf counter instrumentation of the ncache. Parameters: pc  perf counter instance to use

void PINT_ncache_finalize (  void   )

Finalizes and destroys the ncache, frees all cached entries.

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int PINT_ncache_get_cached_entry (  const char *  entry, PVFS_object_ref *  entry_ref, const PVFS_object_ref *  parent_ref )

Retrieves a _copy_ of a cached object reference, and reports the status to indicate if they are valid or not. Returns: 0 on success, -PVFS_error on failure Parameters: entry  path of obect to look up entry_ref  PVFS2 object looked up parent_ref  Parent of PVFS2 object

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int PINT_ncache_get_info (  enum PINT_ncache_options  option, unsigned int *  arg )

Retrieves parameters from the ncache. 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_ncache_initialize (  void   )

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

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void PINT_ncache_invalidate (  const char *  entry, const PVFS_object_ref *  parent_ref )

Invalidates a cache entry (if present). Parameters: entry  path of obect parent_ref  Parent of PVFS2 object

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int PINT_ncache_set_info (  enum PINT_ncache_options  option, unsigned int  arg )

Sets optional parameters in the ncache. 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_ncache_update (  const char *  entry, const PVFS_object_ref *  entry_ref, const PVFS_object_ref *  parent_ref )

Adds a name to the cache, or updates it if already present. The given name is _copied_ into the cache. Note: NOTE: All previous information for the object will be discarded, even if there is still time remaining before it expires. Returns: 0 on success, -PVFS_error on failure Parameters: entry  entry to update entry_ref  entry ref to update parent_ref  parent ref to update

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Variable Documentation

struct PINT_perf_key ncache_keys[]

ncache performance counter keys

struct PINT_perf_key ncache_keys[]

Initial value: { {"NCACHE_NUM_ENTRIES", PERF_NCACHE_NUM_ENTRIES, PINT_PERF_PRESERVE}, {"NCACHE_SOFT_LIMIT", PERF_NCACHE_SOFT_LIMIT, PINT_PERF_PRESERVE}, {"NCACHE_HARD_LIMIT", PERF_NCACHE_HARD_LIMIT, PINT_PERF_PRESERVE}, {"NCACHE_HITS", PERF_NCACHE_HITS, 0}, {"NCACHE_MISSES", PERF_NCACHE_MISSES, 0}, {"NCACHE_UPDATES", PERF_NCACHE_UPDATES, 0}, {"NCACHE_PURGES", PERF_NCACHE_PURGES, 0}, {"NCACHE_REPLACEMENTS", PERF_NCACHE_REPLACEMENTS, 0}, {"NCACHE_DELETIONS", PERF_NCACHE_DELETIONS, 0}, {"NCACHE_ENABLED", PERF_NCACHE_ENABLED, PINT_PERF_PRESERVE}, {NULL, 0, 0}, } ncache performance counter keys

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