From 0a99a16741977ef2b10ebee8198692e818f8b700 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Sun, 18 Jun 2023 12:45:50 +0300 Subject: [PATCH 2/9] Pass background worker entry in the parameter file This makes it possible to move InitProcess later in SubPostmasterMain (in next commit), as we don't need an lwlock and hence a PGPROC entry to get the background worker entry anymore. --- src/backend/postmaster/bgworker.c | 21 ------------ src/backend/postmaster/postmaster.c | 37 ++++++++++++++------- src/include/postmaster/bgworker_internals.h | 4 --- 3 files changed, 25 insertions(+), 37 deletions(-) diff --git a/src/backend/postmaster/bgworker.c b/src/backend/postmaster/bgworker.c index 07ac68f50bc..b7140306e43 100644 --- a/src/backend/postmaster/bgworker.c +++ b/src/backend/postmaster/bgworker.c @@ -628,27 +628,6 @@ ResetBackgroundWorkerCrashTimes(void) } } -#ifdef EXEC_BACKEND -/* - * In EXEC_BACKEND mode, workers use this to retrieve their details from - * shared memory. - */ -BackgroundWorker * -BackgroundWorkerEntry(int slotno) -{ - static BackgroundWorker myEntry; - BackgroundWorkerSlot *slot; - - Assert(slotno < BackgroundWorkerData->total_slots); - slot = &BackgroundWorkerData->slot[slotno]; - Assert(slot->in_use); - - /* must copy this in case we don't intend to retain shmem access */ - memcpy(&myEntry, &slot->worker, sizeof myEntry); - return &myEntry; -} -#endif - /* * Complain about the BackgroundWorker definition using error level elevel. * Return true if it looks ok, false if not (unless elevel >= ERROR, in diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index ee9e24e4e74..a7a9e061c5b 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -540,6 +540,8 @@ typedef struct #endif char my_exec_path[MAXPGPATH]; char pkglib_path[MAXPGPATH]; + + BackgroundWorker MyBgworkerEntry; } BackendParameters; static void read_backend_variables(char *id, Port *port); @@ -4867,7 +4869,7 @@ SubPostmasterMain(int argc, char *argv[]) strcmp(argv[1], "--forkavlauncher") == 0 || strcmp(argv[1], "--forkavworker") == 0 || strcmp(argv[1], "--forkaux") == 0 || - strncmp(argv[1], "--forkbgworker=", 15) == 0) + strncmp(argv[1], "--forkbgworker", 14) == 0) PGSharedMemoryReAttach(); else PGSharedMemoryNoReAttach(); @@ -4998,10 +5000,8 @@ SubPostmasterMain(int argc, char *argv[]) AutoVacWorkerMain(argc - 2, argv + 2); /* does not return */ } - if (strncmp(argv[1], "--forkbgworker=", 15) == 0) + if (strncmp(argv[1], "--forkbgworker", 14) == 0) { - int shmem_slot; - /* do this as early as possible; in particular, before InitProcess() */ IsBackgroundWorker = true; @@ -5014,10 +5014,6 @@ SubPostmasterMain(int argc, char *argv[]) /* Attach process to shared data structures */ CreateSharedMemoryAndSemaphores(); - /* Fetch MyBgworkerEntry from shared memory */ - shmem_slot = atoi(argv[1] + 15); - MyBgworkerEntry = BackgroundWorkerEntry(shmem_slot); - StartBackgroundWorker(); } if (strcmp(argv[1], "--forklog") == 0) @@ -5662,13 +5658,14 @@ BackgroundWorkerUnblockSignals(void) #ifdef EXEC_BACKEND static pid_t -bgworker_forkexec(int shmem_slot) +bgworker_forkexec(BackgroundWorker *worker) { char *av[10]; int ac = 0; char forkav[MAXPGPATH]; + pid_t result; - snprintf(forkav, MAXPGPATH, "--forkbgworker=%d", shmem_slot); + snprintf(forkav, MAXPGPATH, "--forkbgworker"); av[ac++] = "postgres"; av[ac++] = forkav; @@ -5677,7 +5674,11 @@ bgworker_forkexec(int shmem_slot) Assert(ac < lengthof(av)); - return postmaster_forkexec(ac, av); + MyBgworkerEntry = worker; + result = postmaster_forkexec(ac, av); + MyBgworkerEntry = NULL; + + return result; } #endif @@ -5718,7 +5719,7 @@ do_start_bgworker(RegisteredBgWorker *rw) rw->rw_worker.bgw_name))); #ifdef EXEC_BACKEND - switch ((worker_pid = bgworker_forkexec(rw->rw_shmem_slot))) + switch ((worker_pid = bgworker_forkexec(&rw->rw_worker))) #else switch ((worker_pid = fork_process())) #endif @@ -6120,6 +6121,11 @@ save_backend_variables(BackendParameters *param, Port *port, strlcpy(param->pkglib_path, pkglib_path, MAXPGPATH); + if (MyBgworkerEntry) + memcpy(¶m->MyBgworkerEntry, MyBgworkerEntry, sizeof(BackgroundWorker)); + else + memset(¶m->MyBgworkerEntry, 0, sizeof(BackgroundWorker)); + return true; } @@ -6350,6 +6356,13 @@ restore_backend_variables(BackendParameters *param, Port *port) strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH); + if (param->MyBgworkerEntry.bgw_name[0] != '\0') + { + MyBgworkerEntry = (BackgroundWorker *) + MemoryContextAlloc(TopMemoryContext, sizeof(BackgroundWorker)); + memcpy(MyBgworkerEntry, ¶m->MyBgworkerEntry, sizeof(BackgroundWorker)); + } + /* * We need to restore fd.c's counts of externally-opened FDs; to avoid * confusion, be sure to do this after restoring max_safe_fds. (Note: diff --git a/src/include/postmaster/bgworker_internals.h b/src/include/postmaster/bgworker_internals.h index 4ad63fd9bd7..7fa7ee2d878 100644 --- a/src/include/postmaster/bgworker_internals.h +++ b/src/include/postmaster/bgworker_internals.h @@ -57,8 +57,4 @@ extern void ResetBackgroundWorkerCrashTimes(void); /* Function to start a background worker, called from postmaster.c */ extern void StartBackgroundWorker(void) pg_attribute_noreturn(); -#ifdef EXEC_BACKEND -extern BackgroundWorker *BackgroundWorkerEntry(int slotno); -#endif - #endif /* BGWORKER_INTERNALS_H */ -- 2.30.2