FD.io VPP  v21.06-3-gbb25fbf28
Vector Packet Processing
maplog.h
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2017 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef __included_maplog_h__
17 #define __included_maplog_h__
18 
19 /** @file
20  @brief mmap-based thread-safe fixed-size record double-buffered logging.
21 
22  This scheme should be about as fast as practicable. By fiat, log
23  records are rounded to a multiple of CLIB_CACHE_LINE_BYTES.
24  Consumer code calls clib_maplog_get_entry(...) to obtain a pointer
25  to a log entry.
26 
27  We use an atomic ticket-counter to dole out log entries. Whichever
28  client thread crosses the double-buffer boundary is in charge of
29  replacing the log segment which just filled.
30 */
31 
32 #include <vppinfra/clib.h>
33 #include <vppinfra/cache.h>
34 #include <vppinfra/format.h>
35 #include <string.h>
36 #include <sys/types.h>
37 #include <sys/stat.h>
38 #include <fcntl.h>
39 #include <sys/mman.h>
40 
41 /** Maplog log file header segment. In a separate file */
42 
43 typedef struct
44 {
45  u8 maplog_major_version; /**< library major version number */
46  u8 maplog_minor_version; /**< library minor version number */
47  u8 maplog_patch_version; /**< library patch version number */
48  u8 maplog_flag_wrapped; /**< log has wrapped */
49  u32 application_id; /**< application identifier */
50  u8 application_major_version; /**< application major version number */
51  u8 application_minor_version; /**< application minor version number */
52  u8 application_patch_version; /**< application patch version number */
53  u8 maplog_flag_circular; /**< log is circular */
54  u32 record_size_in_cachelines; /**< record size in cache lines */
55  u32 cacheline_size; /**< cache line size */
56  u64 file_size_in_records; /**< file size in records */
57  u64 number_of_records; /**< number of records in entire log */
58  u64 number_of_files; /**< number of files in entire log */
59  u8 file_basename[256]; /**< file basename */
61 
62 #define MAPLOG_MAJOR_VERSION 1
63 #define MAPLOG_MINOR_VERSION 1
64 #define MAPLOG_PATCH_VERSION 0
65 
66 /** Process-private main data structure */
67 
68 typedef struct
69 {
70  CLIB_CACHE_LINE_ALIGN_MARK (cacheline1);
71  /** rw cache line: atomic ticket-counter, file index */
73  /** file size in records, rounded to a power of two */
75  u32 log2_file_size_in_records; /**< lg file size in records */
76  volatile u32 current_file_index; /**< current file index */
77  volatile u32 flags; /**< flags, currently just "init" or not */
78 
79  /* read-mostly cache line: size parameters, file names, etc. */
80  CLIB_CACHE_LINE_ALIGN_MARK (cacheline2);
81  u32 record_size_in_cachelines; /**< record size in cache lines */
82 
83  /* double-buffered mmap'ed logfiles */
84  volatile u8 *file_baseva[2]; /**< active segment base addresses */
85  u8 *filenames[2]; /**< active segment file names */
86  /* vector not c-string */
87  u8 *file_basename; /**< basename, e.g. "/tmp/mylog" */
88  u8 *header_filename; /**< log header file name */
90 
91 /* flag bits */
92 #define CLIB_MAPLOG_FLAG_INIT (1<<0)
93 #define CLIB_MAPLOG_FLAG_CIRCULAR (1<<1)
94 #define CLIB_MAPLOG_FLAG_WRAPPED (1<<2)
95 
96 /** log initialization structure */
97 typedef struct
98 {
99  clib_maplog_main_t *mm; /**< pointer to the main structure */
100  char *file_basename; /**< file base name */
101  u64 file_size_in_bytes; /**< file size in bytes */
102  u32 record_size_in_bytes; /**< record size in bytes */
103  u32 application_id; /**< application identifier */
104  u8 application_major_version; /**< application major version number */
105  u8 application_minor_version; /**< application minor version number */
106  u8 application_patch_version; /**< application patch version number */
107  u8 maplog_is_circular; /**< single, circular log */
109 
110 /* function prototypes */
111 
115 int clib_maplog_process (char *file_basename, void *fp_arg);
116 
118 
119 u8 *_clib_maplog_get_entry_slowpath (clib_maplog_main_t * mm,
120  u64 my_record_index);
121 
122 /**
123  * @brief Obtain a log entry pointer
124  *
125  * Increments the atomic ticket counter, and returns a pointer to
126  * the newly-allocated log entry. The slowpath function replaces
127  * a full log segment with a new/fresh/empty log segment
128  *
129  * @param[in] mm maplog object pointer
130  * @return pointer to the allocated log entry
131  */
132 static inline void *
134 {
135  u64 my_record_index;
136  u8 *rv;
137 
139 
140  my_record_index = clib_atomic_fetch_add (&mm->next_record_index, 1);
141 
142  /* Time to unmap and create a new logfile? */
143  if (PREDICT_FALSE ((my_record_index & (mm->file_size_in_records - 1)) == 0))
144  {
145  /* Regular log? Switch file... */
146  if (!(mm->flags & CLIB_MAPLOG_FLAG_CIRCULAR))
147  {
148  /* Yes, but not the very first time... (;-)... */
149  if (my_record_index)
150  return _clib_maplog_get_entry_slowpath (mm, my_record_index);
151  }
152  else /* Circular log: set the wrap bit and move along */
154  /* FALLTHROUGH */
155  }
156 
157  rv = (u8 *)
158  mm->file_baseva[(my_record_index >> mm->log2_file_size_in_records) & 1] +
159  (my_record_index & (mm->file_size_in_records - 1))
161 
162  return rv;
163 }
164 
165 #endif /* __included_maplog_h__ */
166 
167 /*
168  * fd.io coding-style-patch-verification: ON
169  *
170  * Local Variables:
171  * eval: (c-set-style "gnu")
172  * End:
173  */
clib_maplog_header_t::maplog_flag_circular
u8 maplog_flag_circular
log is circular
Definition: maplog.h:53
CLIB_MAPLOG_FLAG_WRAPPED
#define CLIB_MAPLOG_FLAG_WRAPPED
Definition: maplog.h:94
clib_maplog_init_args_t::mm
clib_maplog_main_t * mm
pointer to the main structure
Definition: maplog.h:99
clib_maplog_process
int clib_maplog_process(char *file_basename, void *fp_arg)
Process a complete maplog.
Definition: maplog.c:384
clib_maplog_get_entry
static void * clib_maplog_get_entry(clib_maplog_main_t *mm)
Obtain a log entry pointer.
Definition: maplog.h:133
clib_maplog_header_t::file_size_in_records
u64 file_size_in_records
file size in records
Definition: maplog.h:56
clib_maplog_init_args_t::application_patch_version
u8 application_patch_version
application patch version number
Definition: maplog.h:106
CLIB_CACHE_LINE_ALIGN_MARK
#define CLIB_CACHE_LINE_ALIGN_MARK(mark)
Definition: cache.h:60
clib.h
string.h
clib_maplog_main_t::file_baseva
volatile u8 * file_baseva[2]
active segment base addresses
Definition: maplog.h:84
clib_maplog_header_t
Maplog log file header segment.
Definition: maplog.h:43
clib_maplog_main_t::header_filename
u8 * header_filename
log header file name
Definition: maplog.h:88
clib_maplog_header_t::maplog_major_version
u8 maplog_major_version
library major version number
Definition: maplog.h:45
clib_maplog_main_t::flags
volatile u32 flags
flags, currently just "init" or not
Definition: maplog.h:77
clib_maplog_header_t::number_of_files
u64 number_of_files
number of files in entire log
Definition: maplog.h:58
clib_maplog_header_t::application_patch_version
u8 application_patch_version
application patch version number
Definition: maplog.h:52
clib_maplog_header_t::maplog_flag_wrapped
u8 maplog_flag_wrapped
log has wrapped
Definition: maplog.h:48
format_maplog_header
format_function_t format_maplog_header
Definition: maplog.h:117
clib_maplog_close
void clib_maplog_close(clib_maplog_main_t *mm)
Close a mapped log, and update the log header file.
Definition: maplog.c:299
clib_maplog_header_t::application_major_version
u8 application_major_version
application major version number
Definition: maplog.h:50
PREDICT_FALSE
#define PREDICT_FALSE(x)
Definition: clib.h:124
clib_maplog_init_args_t
log initialization structure
Definition: maplog.h:97
clib_maplog_header_t::maplog_patch_version
u8 maplog_patch_version
library patch version number
Definition: maplog.h:47
clib_maplog_init_args_t::application_major_version
u8 application_major_version
application major version number
Definition: maplog.h:104
format.h
clib_maplog_main_t::file_size_in_records
u64 file_size_in_records
file size in records, rounded to a power of two
Definition: maplog.h:74
clib_maplog_init
int clib_maplog_init(clib_maplog_init_args_t *ap)
Initialize a maplog object.
Definition: maplog.c:28
CLIB_CACHE_LINE_BYTES
#define CLIB_CACHE_LINE_BYTES
Definition: cache.h:59
clib_maplog_main_t::current_file_index
volatile u32 current_file_index
current file index
Definition: maplog.h:76
clib_atomic_fetch_add
#define clib_atomic_fetch_add(a, b)
Definition: atomics.h:23
format_function_t
u8 *() format_function_t(u8 *s, va_list *args)
Definition: format.h:48
clib_maplog_init_args_t::application_minor_version
u8 application_minor_version
application minor version number
Definition: maplog.h:105
clib_maplog_update_header
void clib_maplog_update_header(clib_maplog_main_t *mm)
Update a mapped log header file.
Definition: maplog.c:246
clib_maplog_header_t::maplog_minor_version
u8 maplog_minor_version
library minor version number
Definition: maplog.h:46
clib_maplog_header_t::record_size_in_cachelines
u32 record_size_in_cachelines
record size in cache lines
Definition: maplog.h:54
clib_maplog_main_t
Process-private main data structure.
Definition: maplog.h:68
u64
unsigned long u64
Definition: types.h:89
ASSERT
#define ASSERT(truth)
Definition: error_bootstrap.h:69
cache.h
u32
unsigned int u32
Definition: types.h:88
clib_maplog_main_t::next_record_index
volatile u64 next_record_index
rw cache line: atomic ticket-counter, file index
Definition: maplog.h:72
clib_maplog_init_args_t::file_size_in_bytes
u64 file_size_in_bytes
file size in bytes
Definition: maplog.h:101
clib_maplog_init_args_t::application_id
u32 application_id
application identifier
Definition: maplog.h:103
u8
unsigned char u8
Definition: types.h:56
clib_maplog_header_t::application_minor_version
u8 application_minor_version
application minor version number
Definition: maplog.h:51
clib_maplog_main_t::record_size_in_cachelines
u32 record_size_in_cachelines
record size in cache lines
Definition: maplog.h:81
rv
int __clib_unused rv
Definition: application.c:491
CLIB_MAPLOG_FLAG_INIT
#define CLIB_MAPLOG_FLAG_INIT
Definition: maplog.h:92
clib_maplog_init_args_t::file_basename
char * file_basename
file base name
Definition: maplog.h:100
clib_maplog_init_args_t::record_size_in_bytes
u32 record_size_in_bytes
record size in bytes
Definition: maplog.h:102
clib_maplog_init_args_t::maplog_is_circular
u8 maplog_is_circular
single, circular log
Definition: maplog.h:107
clib_maplog_header_t::number_of_records
u64 number_of_records
number of records in entire log
Definition: maplog.h:57
CLIB_MAPLOG_FLAG_CIRCULAR
#define CLIB_MAPLOG_FLAG_CIRCULAR
Definition: maplog.h:93
clib_maplog_header_t::application_id
u32 application_id
application identifier
Definition: maplog.h:49
clib_maplog_main_t::log2_file_size_in_records
u32 log2_file_size_in_records
lg file size in records
Definition: maplog.h:75
clib_maplog_header_t::cacheline_size
u32 cacheline_size
cache line size
Definition: maplog.h:55
clib_maplog_main_t::file_basename
u8 * file_basename
basename, e.g.
Definition: maplog.h:87