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ipci.c
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1 /*-------------------------------------------------------------------------
2  *
3  * ipci.c
4  * POSTGRES inter-process communication initialization code.
5  *
6  * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
7  * Portions Copyright (c) 1994, Regents of the University of California
8  *
9  *
10  * IDENTIFICATION
11  * src/backend/storage/ipc/ipci.c
12  *
13  *-------------------------------------------------------------------------
14  */
15 #include "postgres.h"
16 
17 #include "access/clog.h"
18 #include "access/commit_ts.h"
19 #include "access/heapam.h"
20 #include "access/multixact.h"
21 #include "access/nbtree.h"
22 #include "access/subtrans.h"
23 #include "access/syncscan.h"
24 #include "access/twophase.h"
25 #include "access/xlogprefetcher.h"
26 #include "access/xlogrecovery.h"
27 #include "commands/async.h"
28 #include "miscadmin.h"
29 #include "pgstat.h"
30 #include "postmaster/autovacuum.h"
32 #include "postmaster/bgwriter.h"
33 #include "postmaster/postmaster.h"
35 #include "replication/origin.h"
36 #include "replication/slot.h"
38 #include "replication/walsender.h"
39 #include "storage/bufmgr.h"
40 #include "storage/dsm.h"
41 #include "storage/ipc.h"
42 #include "storage/pg_shmem.h"
43 #include "storage/pmsignal.h"
44 #include "storage/predicate.h"
45 #include "storage/proc.h"
46 #include "storage/procarray.h"
47 #include "storage/procsignal.h"
48 #include "storage/sinvaladt.h"
49 #include "storage/spin.h"
50 #include "utils/guc.h"
51 #include "utils/snapmgr.h"
52 
53 /* GUCs */
55 
57 
59 
60 /*
61  * RequestAddinShmemSpace
62  * Request that extra shmem space be allocated for use by
63  * a loadable module.
64  *
65  * This may only be called via the shmem_request_hook of a library that is
66  * loaded into the postmaster via shared_preload_libraries. Calls from
67  * elsewhere will fail.
68  */
69 void
71 {
73  elog(FATAL, "cannot request additional shared memory outside shmem_request_hook");
75 }
76 
77 /*
78  * CalculateShmemSize
79  * Calculates the amount of shared memory and number of semaphores needed.
80  *
81  * If num_semaphores is not NULL, it will be set to the number of semaphores
82  * required.
83  */
84 Size
85 CalculateShmemSize(int *num_semaphores)
86 {
87  Size size;
88  int numSemas;
89 
90  /* Compute number of semaphores we'll need */
91  numSemas = ProcGlobalSemas();
92  numSemas += SpinlockSemas();
93 
94  /* Return the number of semaphores if requested by the caller */
95  if (num_semaphores)
96  *num_semaphores = numSemas;
97 
98  /*
99  * Size of the Postgres shared-memory block is estimated via moderately-
100  * accurate estimates for the big hogs, plus 100K for the stuff that's too
101  * small to bother with estimating.
102  *
103  * We take some care to ensure that the total size request doesn't
104  * overflow size_t. If this gets through, we don't need to be so careful
105  * during the actual allocation phase.
106  */
107  size = 100000;
108  size = add_size(size, PGSemaphoreShmemSize(numSemas));
109  size = add_size(size, SpinlockSemaSize());
111  sizeof(ShmemIndexEnt)));
112  size = add_size(size, dsm_estimate_size());
113  size = add_size(size, BufferShmemSize());
114  size = add_size(size, LockShmemSize());
115  size = add_size(size, PredicateLockShmemSize());
116  size = add_size(size, ProcGlobalShmemSize());
117  size = add_size(size, XLogPrefetchShmemSize());
118  size = add_size(size, XLOGShmemSize());
119  size = add_size(size, XLogRecoveryShmemSize());
120  size = add_size(size, CLOGShmemSize());
121  size = add_size(size, CommitTsShmemSize());
122  size = add_size(size, SUBTRANSShmemSize());
123  size = add_size(size, TwoPhaseShmemSize());
124  size = add_size(size, BackgroundWorkerShmemSize());
125  size = add_size(size, MultiXactShmemSize());
126  size = add_size(size, LWLockShmemSize());
127  size = add_size(size, ProcArrayShmemSize());
128  size = add_size(size, BackendStatusShmemSize());
129  size = add_size(size, SInvalShmemSize());
130  size = add_size(size, PMSignalShmemSize());
131  size = add_size(size, ProcSignalShmemSize());
132  size = add_size(size, CheckpointerShmemSize());
133  size = add_size(size, AutoVacuumShmemSize());
134  size = add_size(size, ReplicationSlotsShmemSize());
135  size = add_size(size, ReplicationOriginShmemSize());
136  size = add_size(size, WalSndShmemSize());
137  size = add_size(size, WalRcvShmemSize());
138  size = add_size(size, PgArchShmemSize());
139  size = add_size(size, ApplyLauncherShmemSize());
140  size = add_size(size, SnapMgrShmemSize());
141  size = add_size(size, BTreeShmemSize());
142  size = add_size(size, SyncScanShmemSize());
143  size = add_size(size, AsyncShmemSize());
144  size = add_size(size, StatsShmemSize());
145 #ifdef EXEC_BACKEND
146  size = add_size(size, ShmemBackendArraySize());
147 #endif
148 
149  /* include additional requested shmem from preload libraries */
150  size = add_size(size, total_addin_request);
151 
152  /* might as well round it off to a multiple of a typical page size */
153  size = add_size(size, 8192 - (size % 8192));
154 
155  return size;
156 }
157 
158 /*
159  * CreateSharedMemoryAndSemaphores
160  * Creates and initializes shared memory and semaphores.
161  *
162  * This is called by the postmaster or by a standalone backend.
163  * It is also called by a backend forked from the postmaster in the
164  * EXEC_BACKEND case. In the latter case, the shared memory segment
165  * already exists and has been physically attached to, but we have to
166  * initialize pointers in local memory that reference the shared structures,
167  * because we didn't inherit the correct pointer values from the postmaster
168  * as we do in the fork() scenario. The easiest way to do that is to run
169  * through the same code as before. (Note that the called routines mostly
170  * check IsUnderPostmaster, rather than EXEC_BACKEND, to detect this case.
171  * This is a bit code-wasteful and could be cleaned up.)
172  */
173 void
175 {
176  PGShmemHeader *shim = NULL;
177 
178  if (!IsUnderPostmaster)
179  {
180  PGShmemHeader *seghdr;
181  Size size;
182  int numSemas;
183 
184  /* Compute the size of the shared-memory block */
185  size = CalculateShmemSize(&numSemas);
186  elog(DEBUG3, "invoking IpcMemoryCreate(size=%zu)", size);
187 
188  /*
189  * Create the shmem segment
190  */
191  seghdr = PGSharedMemoryCreate(size, &shim);
192 
193  InitShmemAccess(seghdr);
194 
195  /*
196  * Create semaphores
197  */
198  PGReserveSemaphores(numSemas);
199 
200  /*
201  * If spinlocks are disabled, initialize emulation layer (which
202  * depends on semaphores, so the order is important here).
203  */
204 #ifndef HAVE_SPINLOCKS
206 #endif
207  }
208  else
209  {
210  /*
211  * We are reattaching to an existing shared memory segment. This
212  * should only be reached in the EXEC_BACKEND case.
213  */
214 #ifndef EXEC_BACKEND
215  elog(PANIC, "should be attached to shared memory already");
216 #endif
217  }
218 
219  /*
220  * Set up shared memory allocation mechanism
221  */
222  if (!IsUnderPostmaster)
224 
225  /*
226  * Now initialize LWLocks, which do shared memory allocation and are
227  * needed for InitShmemIndex.
228  */
229  CreateLWLocks();
230 
231  /*
232  * Set up shmem.c index hashtable
233  */
234  InitShmemIndex();
235 
236  dsm_shmem_init();
237 
238  /*
239  * Set up xlog, clog, and buffers
240  */
241  XLOGShmemInit();
244  CLOGShmemInit();
248  InitBufferPool();
249 
250  /*
251  * Set up lock manager
252  */
253  InitLocks();
254 
255  /*
256  * Set up predicate lock manager
257  */
259 
260  /*
261  * Set up process table
262  */
263  if (!IsUnderPostmaster)
264  InitProcGlobal();
269 
270  /*
271  * Set up shared-inval messaging
272  */
274 
275  /*
276  * Set up interprocess signaling mechanisms
277  */
284  WalSndShmemInit();
285  WalRcvShmemInit();
286  PgArchShmemInit();
288 
289  /*
290  * Set up other modules that need some shared memory space
291  */
292  SnapMgrInit();
293  BTreeShmemInit();
295  AsyncShmemInit();
296  StatsShmemInit();
297 
298 #ifdef EXEC_BACKEND
299 
300  /*
301  * Alloc the win32 shared backend array
302  */
303  if (!IsUnderPostmaster)
304  ShmemBackendArrayAllocation();
305 #endif
306 
307  /* Initialize dynamic shared memory facilities. */
308  if (!IsUnderPostmaster)
310 
311  /*
312  * Now give loadable modules a chance to set up their shmem allocations
313  */
314  if (shmem_startup_hook)
316 }
317 
318 /*
319  * InitializeShmemGUCs
320  *
321  * This function initializes runtime-computed GUCs related to the amount of
322  * shared memory required for the current configuration.
323  */
324 void
326 {
327  char buf[64];
328  Size size_b;
329  Size size_mb;
330  Size hp_size;
331 
332  /*
333  * Calculate the shared memory size and round up to the nearest megabyte.
334  */
335  size_b = CalculateShmemSize(NULL);
336  size_mb = add_size(size_b, (1024 * 1024) - 1) / (1024 * 1024);
337  sprintf(buf, "%zu", size_mb);
338  SetConfigOption("shared_memory_size", buf,
340 
341  /*
342  * Calculate the number of huge pages required.
343  */
344  GetHugePageSize(&hp_size, NULL);
345  if (hp_size != 0)
346  {
347  Size hp_required;
348 
349  hp_required = add_size(size_b / hp_size, 1);
350  sprintf(buf, "%zu", hp_required);
351  SetConfigOption("shared_memory_size_in_huge_pages", buf,
353  }
354 }
Size AsyncShmemSize(void)
Definition: async.c:516
void AsyncShmemInit(void)
Definition: async.c:533
Size AutoVacuumShmemSize(void)
Definition: autovacuum.c:3325
void AutoVacuumShmemInit(void)
Definition: autovacuum.c:3344
void CreateSharedBackendStatus(void)
Size BackendStatusShmemSize(void)
void BackgroundWorkerShmemInit(void)
Definition: bgworker.c:158
Size BackgroundWorkerShmemSize(void)
Definition: bgworker.c:142
Size BufferShmemSize(void)
Definition: buf_init.c:157
void InitBufferPool(void)
Definition: buf_init.c:68
size_t Size
Definition: c.h:541
void CheckpointerShmemInit(void)
Definition: checkpointer.c:888
Size CheckpointerShmemSize(void)
Definition: checkpointer.c:869
void CLOGShmemInit(void)
Definition: clog.c:695
Size CLOGShmemSize(void)
Definition: clog.c:689
Size CommitTsShmemSize(void)
Definition: commit_ts.c:525
void CommitTsShmemInit(void)
Definition: commit_ts.c:536
size_t dsm_estimate_size(void)
Definition: dsm.c:444
void dsm_postmaster_startup(PGShmemHeader *shim)
Definition: dsm.c:150
void dsm_shmem_init(void)
Definition: dsm.c:453
Size hash_estimate_size(long num_entries, Size entrysize)
Definition: dynahash.c:781
#define DEBUG3
Definition: elog.h:24
#define FATAL
Definition: elog.h:37
#define PANIC
Definition: elog.h:38
bool IsUnderPostmaster
Definition: globals.c:113
void SetConfigOption(const char *name, const char *value, GucContext context, GucSource source)
Definition: guc.c:4158
@ PGC_S_DYNAMIC_DEFAULT
Definition: guc.h:110
@ PGC_INTERNAL
Definition: guc.h:69
void(* shmem_startup_hook_type)(void)
Definition: ipc.h:22
static Size total_addin_request
Definition: ipci.c:58
int shared_memory_type
Definition: ipci.c:54
shmem_startup_hook_type shmem_startup_hook
Definition: ipci.c:56
void RequestAddinShmemSpace(Size size)
Definition: ipci.c:70
Size CalculateShmemSize(int *num_semaphores)
Definition: ipci.c:85
void InitializeShmemGUCs(void)
Definition: ipci.c:325
void CreateSharedMemoryAndSemaphores(void)
Definition: ipci.c:174
Size ApplyLauncherShmemSize(void)
Definition: launcher.c:688
void ApplyLauncherShmemInit(void)
Definition: launcher.c:736
void InitLocks(void)
Definition: lock.c:405
Size LockShmemSize(void)
Definition: lock.c:3609
void CreateLWLocks(void)
Definition: lwlock.c:467
Size LWLockShmemSize(void)
Definition: lwlock.c:437
bool process_shmem_requests_in_progress
Definition: miscinit.c:1769
void MultiXactShmemInit(void)
Definition: multixact.c:1842
Size MultiXactShmemSize(void)
Definition: multixact.c:1825
void BTreeShmemInit(void)
Definition: nbtutils.c:2083
Size BTreeShmemSize(void)
Definition: nbtutils.c:2070
Size ReplicationOriginShmemSize(void)
Definition: origin.c:502
void ReplicationOriginShmemInit(void)
Definition: origin.c:522
#define DEFAULT_SHARED_MEMORY_TYPE
Definition: pg_shmem.h:74
static char * buf
Definition: pg_test_fsync.c:67
Size PgArchShmemSize(void)
Definition: pgarch.c:149
void PgArchShmemInit(void)
Definition: pgarch.c:160
void StatsShmemInit(void)
Definition: pgstat_shmem.c:140
Size StatsShmemSize(void)
Definition: pgstat_shmem.c:126
Size PMSignalShmemSize(void)
Definition: pmsignal.c:129
void PMSignalShmemInit(void)
Definition: pmsignal.c:144
#define sprintf
Definition: port.h:240
Size PGSemaphoreShmemSize(int maxSemas)
Definition: posix_sema.c:165
void PGReserveSemaphores(int maxSemas)
Definition: posix_sema.c:196
void InitPredicateLocks(void)
Definition: predicate.c:1153
Size PredicateLockShmemSize(void)
Definition: predicate.c:1356
Size ProcArrayShmemSize(void)
Definition: procarray.c:379
void CreateSharedProcArray(void)
Definition: procarray.c:421
void ProcSignalShmemInit(void)
Definition: procsignal.c:125
Size ProcSignalShmemSize(void)
Definition: procsignal.c:111
void InitShmemIndex(void)
Definition: shmem.c:292
Size add_size(Size s1, Size s2)
Definition: shmem.c:502
void InitShmemAllocation(void)
Definition: shmem.c:116
void InitShmemAccess(void *seghdr)
Definition: shmem.c:101
#define SHMEM_INDEX_SIZE
Definition: shmem.h:55
Size SInvalShmemSize(void)
Definition: sinvaladt.c:203
void CreateSharedInvalidationState(void)
Definition: sinvaladt.c:227
void ReplicationSlotsShmemInit(void)
Definition: slot.c:135
Size ReplicationSlotsShmemSize(void)
Definition: slot.c:117
void SnapMgrInit(void)
Definition: snapmgr.c:214
Size SnapMgrShmemSize(void)
Definition: snapmgr.c:198
Size SpinlockSemaSize(void)
Definition: spin.c:55
void SpinlockSemaInit(void)
Definition: spin.c:77
int SpinlockSemas(void)
Definition: spin.c:64
Size ProcGlobalShmemSize(void)
Definition: proc.c:102
int ProcGlobalSemas(void)
Definition: proc.c:124
void InitProcGlobal(void)
Definition: proc.c:159
void SUBTRANSShmemInit(void)
Definition: subtrans.c:191
Size SUBTRANSShmemSize(void)
Definition: subtrans.c:185
void SyncScanShmemInit(void)
Definition: syncscan.c:135
Size SyncScanShmemSize(void)
Definition: syncscan.c:126
PGShmemHeader * PGSharedMemoryCreate(Size size, PGShmemHeader **shim)
Definition: sysv_shmem.c:691
void GetHugePageSize(Size *hugepagesize, int *mmap_flags)
Definition: sysv_shmem.c:478
Size TwoPhaseShmemSize(void)
Definition: twophase.c:240
void TwoPhaseShmemInit(void)
Definition: twophase.c:256
void WalRcvShmemInit(void)
Size WalRcvShmemSize(void)
void WalSndShmemInit(void)
Definition: walsender.c:3264
Size WalSndShmemSize(void)
Definition: walsender.c:3252
void XLOGShmemInit(void)
Definition: xlog.c:4528
Size XLOGShmemSize(void)
Definition: xlog.c:4478
size_t XLogPrefetchShmemSize(void)
void XLogPrefetchShmemInit(void)
Size XLogRecoveryShmemSize(void)
Definition: xlogrecovery.c:446
void XLogRecoveryShmemInit(void)
Definition: xlogrecovery.c:457