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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) 1996-2017, 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/twophase.h"
24 #include "commands/async.h"
25 #include "miscadmin.h"
26 #include "pgstat.h"
27 #include "postmaster/autovacuum.h"
29 #include "postmaster/bgwriter.h"
30 #include "postmaster/postmaster.h"
32 #include "replication/slot.h"
34 #include "replication/walsender.h"
35 #include "replication/origin.h"
36 #include "storage/bufmgr.h"
37 #include "storage/dsm.h"
38 #include "storage/ipc.h"
39 #include "storage/pg_shmem.h"
40 #include "storage/pmsignal.h"
41 #include "storage/predicate.h"
42 #include "storage/proc.h"
43 #include "storage/procarray.h"
44 #include "storage/procsignal.h"
45 #include "storage/sinvaladt.h"
46 #include "storage/spin.h"
47 #include "utils/backend_random.h"
48 #include "utils/snapmgr.h"
49 
50 
52 
54 static bool addin_request_allowed = true;
55 
56 
57 /*
58  * RequestAddinShmemSpace
59  * Request that extra shmem space be allocated for use by
60  * a loadable module.
61  *
62  * This is only useful if called from the _PG_init hook of a library that
63  * is loaded into the postmaster via shared_preload_libraries. Once
64  * shared memory has been allocated, calls will be ignored. (We could
65  * raise an error, but it seems better to make it a no-op, so that
66  * libraries containing such calls can be reloaded if needed.)
67  */
68 void
70 {
72  return; /* too late */
74 }
75 
76 
77 /*
78  * CreateSharedMemoryAndSemaphores
79  * Creates and initializes shared memory and semaphores.
80  *
81  * This is called by the postmaster or by a standalone backend.
82  * It is also called by a backend forked from the postmaster in the
83  * EXEC_BACKEND case. In the latter case, the shared memory segment
84  * already exists and has been physically attached to, but we have to
85  * initialize pointers in local memory that reference the shared structures,
86  * because we didn't inherit the correct pointer values from the postmaster
87  * as we do in the fork() scenario. The easiest way to do that is to run
88  * through the same code as before. (Note that the called routines mostly
89  * check IsUnderPostmaster, rather than EXEC_BACKEND, to detect this case.
90  * This is a bit code-wasteful and could be cleaned up.)
91  *
92  * If "makePrivate" is true then we only need private memory, not shared
93  * memory. This is true for a standalone backend, false for a postmaster.
94  */
95 void
96 CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
97 {
98  PGShmemHeader *shim = NULL;
99 
100  if (!IsUnderPostmaster)
101  {
102  PGShmemHeader *seghdr;
103  Size size;
104  int numSemas;
105 
106  /* Compute number of semaphores we'll need */
107  numSemas = ProcGlobalSemas();
108  numSemas += SpinlockSemas();
109 
110  /*
111  * Size of the Postgres shared-memory block is estimated via
112  * moderately-accurate estimates for the big hogs, plus 100K for the
113  * stuff that's too small to bother with estimating.
114  *
115  * We take some care during this phase to ensure that the total size
116  * request doesn't overflow size_t. If this gets through, we don't
117  * need to be so careful during the actual allocation phase.
118  */
119  size = 100000;
120  size = add_size(size, PGSemaphoreShmemSize(numSemas));
121  size = add_size(size, SpinlockSemaSize());
123  sizeof(ShmemIndexEnt)));
124  size = add_size(size, BufferShmemSize());
125  size = add_size(size, LockShmemSize());
126  size = add_size(size, PredicateLockShmemSize());
127  size = add_size(size, ProcGlobalShmemSize());
128  size = add_size(size, XLOGShmemSize());
129  size = add_size(size, CLOGShmemSize());
130  size = add_size(size, CommitTsShmemSize());
131  size = add_size(size, SUBTRANSShmemSize());
132  size = add_size(size, TwoPhaseShmemSize());
133  size = add_size(size, BackgroundWorkerShmemSize());
134  size = add_size(size, MultiXactShmemSize());
135  size = add_size(size, LWLockShmemSize());
136  size = add_size(size, ProcArrayShmemSize());
137  size = add_size(size, BackendStatusShmemSize());
138  size = add_size(size, SInvalShmemSize());
139  size = add_size(size, PMSignalShmemSize());
140  size = add_size(size, ProcSignalShmemSize());
141  size = add_size(size, CheckpointerShmemSize());
142  size = add_size(size, AutoVacuumShmemSize());
143  size = add_size(size, ReplicationSlotsShmemSize());
144  size = add_size(size, ReplicationOriginShmemSize());
145  size = add_size(size, WalSndShmemSize());
146  size = add_size(size, WalRcvShmemSize());
147  size = add_size(size, ApplyLauncherShmemSize());
148  size = add_size(size, SnapMgrShmemSize());
149  size = add_size(size, BTreeShmemSize());
150  size = add_size(size, SyncScanShmemSize());
151  size = add_size(size, AsyncShmemSize());
152  size = add_size(size, BackendRandomShmemSize());
153 #ifdef EXEC_BACKEND
154  size = add_size(size, ShmemBackendArraySize());
155 #endif
156 
157  /* freeze the addin request size and include it */
158  addin_request_allowed = false;
159  size = add_size(size, total_addin_request);
160 
161  /* might as well round it off to a multiple of a typical page size */
162  size = add_size(size, 8192 - (size % 8192));
163 
164  elog(DEBUG3, "invoking IpcMemoryCreate(size=%zu)", size);
165 
166  /*
167  * Create the shmem segment
168  */
169  seghdr = PGSharedMemoryCreate(size, makePrivate, port, &shim);
170 
171  InitShmemAccess(seghdr);
172 
173  /*
174  * Create semaphores
175  */
176  PGReserveSemaphores(numSemas, port);
177 
178  /*
179  * If spinlocks are disabled, initialize emulation layer (which
180  * depends on semaphores, so the order is important here).
181  */
182 #ifndef HAVE_SPINLOCKS
184 #endif
185  }
186  else
187  {
188  /*
189  * We are reattaching to an existing shared memory segment. This
190  * should only be reached in the EXEC_BACKEND case, and even then only
191  * with makePrivate == false.
192  */
193 #ifdef EXEC_BACKEND
194  Assert(!makePrivate);
195 #else
196  elog(PANIC, "should be attached to shared memory already");
197 #endif
198  }
199 
200  /*
201  * Set up shared memory allocation mechanism
202  */
203  if (!IsUnderPostmaster)
205 
206  /*
207  * Now initialize LWLocks, which do shared memory allocation and are
208  * needed for InitShmemIndex.
209  */
210  CreateLWLocks();
211 
212  /*
213  * Set up shmem.c index hashtable
214  */
215  InitShmemIndex();
216 
217  /*
218  * Set up xlog, clog, and buffers
219  */
220  XLOGShmemInit();
221  CLOGShmemInit();
225  InitBufferPool();
226 
227  /*
228  * Set up lock manager
229  */
230  InitLocks();
231 
232  /*
233  * Set up predicate lock manager
234  */
236 
237  /*
238  * Set up process table
239  */
240  if (!IsUnderPostmaster)
241  InitProcGlobal();
246 
247  /*
248  * Set up shared-inval messaging
249  */
251 
252  /*
253  * Set up interprocess signaling mechanisms
254  */
261  WalSndShmemInit();
262  WalRcvShmemInit();
264 
265  /*
266  * Set up other modules that need some shared memory space
267  */
268  SnapMgrInit();
269  BTreeShmemInit();
271  AsyncShmemInit();
273 
274 #ifdef EXEC_BACKEND
275 
276  /*
277  * Alloc the win32 shared backend array
278  */
279  if (!IsUnderPostmaster)
280  ShmemBackendArrayAllocation();
281 #endif
282 
283  /* Initialize dynamic shared memory facilities. */
284  if (!IsUnderPostmaster)
286 
287  /*
288  * Now give loadable modules a chance to set up their shmem allocations
289  */
290  if (shmem_startup_hook)
292 }
void dsm_postmaster_startup(PGShmemHeader *shim)
Definition: dsm.c:145
Size SInvalShmemSize(void)
Definition: sinvaladt.c:204
void RequestAddinShmemSpace(Size size)
Definition: ipci.c:69
void BTreeShmemInit(void)
Definition: nbtutils.c:2014
void(* shmem_startup_hook_type)(void)
Definition: ipc.h:22
Size PMSignalShmemSize(void)
Definition: pmsignal.c:80
Size ReplicationSlotsShmemSize(void)
Definition: slot.c:114
Size BackendRandomShmemSize(void)
#define SHMEM_INDEX_SIZE
Definition: shmem.h:55
void BackendRandomShmemInit(void)
void SUBTRANSShmemInit(void)
Definition: subtrans.c:178
#define DEBUG3
Definition: elog.h:23
Size SpinlockSemaSize(void)
Definition: spin.c:39
void InitShmemAccess(void *seghdr)
Definition: shmem.c:97
void AsyncShmemInit(void)
Definition: async.c:440
void CreateSharedInvalidationState(void)
Definition: sinvaladt.c:219
Size SyncScanShmemSize(void)
Definition: syncscan.c:126
void PGReserveSemaphores(int maxSemas, int port)
Definition: posix_sema.c:193
Size WalSndShmemSize(void)
Definition: walsender.c:2886
void CheckpointerShmemInit(void)
Definition: checkpointer.c:926
Size PredicateLockShmemSize(void)
Definition: predicate.c:1295
Size TwoPhaseShmemSize(void)
Definition: twophase.c:236
void ReplicationOriginShmemInit(void)
Definition: origin.c:457
void WalRcvShmemInit(void)
#define PANIC
Definition: elog.h:53
void XLOGShmemInit(void)
Definition: xlog.c:4843
Size BackgroundWorkerShmemSize(void)
Definition: bgworker.c:143
void ReplicationSlotsShmemInit(void)
Definition: slot.c:132
Size LWLockShmemSize(void)
Definition: lwlock.c:349
Size BTreeShmemSize(void)
Definition: nbtutils.c:2001
void InitProcGlobal(void)
Definition: proc.c:162
void BackgroundWorkerShmemInit(void)
Definition: bgworker.c:159
void MultiXactShmemInit(void)
Definition: multixact.c:1820
void PMSignalShmemInit(void)
Definition: pmsignal.c:95
Size XLOGShmemSize(void)
Definition: xlog.c:4802
void SpinlockSemaInit(void)
Definition: spin.c:76
bool IsUnderPostmaster
Definition: globals.c:100
Size ApplyLauncherShmemSize(void)
Definition: launcher.c:563
void InitBufferPool(void)
Definition: buf_init.c:68
void SnapMgrInit(void)
Definition: snapmgr.c:263
void InitLocks(void)
Definition: lock.c:377
Size ProcGlobalShmemSize(void)
Definition: proc.c:102
static int port
Definition: pg_regress.c:89
static bool addin_request_allowed
Definition: ipci.c:54
Size ProcSignalShmemSize(void)
Definition: procsignal.c:73
shmem_startup_hook_type shmem_startup_hook
Definition: ipci.c:51
Size hash_estimate_size(long num_entries, Size entrysize)
Definition: dynahash.c:711
void TwoPhaseShmemInit(void)
Definition: twophase.c:252
int SpinlockSemas(void)
Definition: spin.c:65
static Size total_addin_request
Definition: ipci.c:53
Size BackendStatusShmemSize(void)
Definition: pgstat.c:2568
Size add_size(Size s1, Size s2)
Definition: shmem.c:475
Size AutoVacuumShmemSize(void)
Definition: autovacuum.c:3371
Size ReplicationOriginShmemSize(void)
Definition: origin.c:437
Size CheckpointerShmemSize(void)
Definition: checkpointer.c:907
Size CLOGShmemSize(void)
Definition: clog.c:444
void CreateSharedBackendStatus(void)
Definition: pgstat.c:2596
Size WalRcvShmemSize(void)
void CreateLWLocks(void)
Definition: lwlock.c:381
#define NULL
Definition: c.h:229
#define Assert(condition)
Definition: c.h:675
void SyncScanShmemInit(void)
Definition: syncscan.c:135
void CreateSharedProcArray(void)
Definition: procarray.c:221
Size AsyncShmemSize(void)
Definition: async.c:423
size_t Size
Definition: c.h:356
PGShmemHeader * PGSharedMemoryCreate(Size size, bool makePrivate, int port, PGShmemHeader **shim)
Definition: sysv_shmem.c:557
Size CommitTsShmemSize(void)
Definition: commit_ts.c:479
void ApplyLauncherShmemInit(void)
Definition: launcher.c:609
Size MultiXactShmemSize(void)
Definition: multixact.c:1803
Size LockShmemSize(void)
Definition: lock.c:3361
Size SUBTRANSShmemSize(void)
Definition: subtrans.c:172
Size BufferShmemSize(void)
Definition: buf_init.c:161
void WalSndShmemInit(void)
Definition: walsender.c:2898
void CLOGShmemInit(void)
Definition: clog.c:450
Size PGSemaphoreShmemSize(int maxSemas)
Definition: posix_sema.c:158
void ProcSignalShmemInit(void)
Definition: procsignal.c:83
void InitShmemIndex(void)
Definition: shmem.c:272
#define elog
Definition: elog.h:219
void InitPredicateLocks(void)
Definition: predicate.c:1104
void AutoVacuumShmemInit(void)
Definition: autovacuum.c:3390
Size SnapMgrShmemSize(void)
Definition: snapmgr.c:247
void CreateSharedMemoryAndSemaphores(bool makePrivate, int port)
Definition: ipci.c:96
Size ProcArrayShmemSize(void)
Definition: procarray.c:179
int ProcGlobalSemas(void)
Definition: proc.c:128
void InitShmemAllocation(void)
Definition: shmem.c:112
void CommitTsShmemInit(void)
Definition: commit_ts.c:490