maplog.h File Reference

mmap-based thread-safe fixed-size record double-buffered logging. More...

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Data Structures
struct	clib_maplog_header_t
	Maplog log file header segment. More...
struct	clib_maplog_main_t
	Process-private main data structure. More...
struct	clib_maplog_init_args_t
	log initialization structure More...

Macros
#define	MAPLOG_MAJOR_VERSION   1
#define	MAPLOG_MINOR_VERSION   1
#define	MAPLOG_PATCH_VERSION   0
#define	CLIB_MAPLOG_FLAG_INIT   (1<<0)
#define	CLIB_MAPLOG_FLAG_CIRCULAR   (1<<1)
#define	CLIB_MAPLOG_FLAG_WRAPPED   (1<<2)

Functions
int	clib_maplog_init (clib_maplog_init_args_t *ap)
	Initialize a maplog object. More...
void	clib_maplog_update_header (clib_maplog_main_t *mm)
	Update a mapped log header file. More...
void	clib_maplog_close (clib_maplog_main_t *mm)
	Close a mapped log, and update the log header file. More...
int	clib_maplog_process (char *file_basename, void *fp_arg)
	Process a complete maplog. More...
static void *	clib_maplog_get_entry (clib_maplog_main_t *mm)
	Obtain a log entry pointer. More...

Variables
format_function_t	format_maplog_header

Detailed Description

mmap-based thread-safe fixed-size record double-buffered logging.

This scheme should be about as fast as practicable. By fiat, log records are rounded to a multiple of CLIB_CACHE_LINE_BYTES. Consumer code calls clib_maplog_get_entry(...) to obtain a pointer to a log entry.

We use an atomic ticket-counter to dole out log entries. Whichever client thread crosses the double-buffer boundary is in charge of replacing the log segment which just filled.

Definition in file maplog.h.

Macro Definition Documentation

#define CLIB_MAPLOG_FLAG_CIRCULAR   (1<<1)

Definition at line 93 of file maplog.h.

#define CLIB_MAPLOG_FLAG_INIT   (1<<0)

Definition at line 92 of file maplog.h.

#define CLIB_MAPLOG_FLAG_WRAPPED   (1<<2)

Definition at line 94 of file maplog.h.

#define MAPLOG_MAJOR_VERSION   1

Definition at line 62 of file maplog.h.

#define MAPLOG_MINOR_VERSION   1

Definition at line 63 of file maplog.h.

#define MAPLOG_PATCH_VERSION   0

Definition at line 64 of file maplog.h.

Function Documentation

void clib_maplog_close

(

clib_maplog_main_t *

mm

)

Close a mapped log, and update the log header file.

Unmap the current log segments. Read the log header. Update the number of records, and number of files

Parameters

Definition at line 299 of file maplog.c.

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static void* clib_maplog_get_entry ( clib_maplog_main_t *  mm )

inlinestatic

Obtain a log entry pointer.

Increments the atomic ticket counter, and returns a pointer to the newly-allocated log entry. The slowpath function replaces a full log segment with a new/fresh/empty log segment

Parameters

[in]

mm

maplog object pointer

Returns

pointer to the allocated log entry

Definition at line 133 of file maplog.h.

int clib_maplog_init

(

clib_maplog_init_args_t *

a

)

Initialize a maplog object.

Compute record and file size parameters Create and map two log segments to seed the process

Parameters

Definition at line 28 of file maplog.c.

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int clib_maplog_process	(	char *	file_basename,
		void *	fp_arg
	)

Process a complete maplog.

Reads the maplog header. Map and process all log segments in order. Calls the callback function once per file with a record count.

Note: if the file header isn't updated by calling clib_maplog_close(), it will appear to have an infinite number of records in an infinite number of files.

So long as the callback function understands that possibility

• by simply ignoring NULL records - the scheme still works...

Parameters

[in]	file_basename	Same basename supplied to clib_maplog_init
[in]	fp_arg	Callback function pointer

Definition at line 384 of file maplog.c.

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void clib_maplog_update_header

(

clib_maplog_main_t *

mm

)

Update a mapped log header file.

Read the log header. Update the number of records, and number of files

Parameters

Definition at line 246 of file maplog.c.

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Variable Documentation

format_function_t format_maplog_header

Definition at line 117 of file maplog.h.