6 files changed, 66 insertions, 36 deletions
diff --git a/src/backend/port/unix_latch.c b/src/backend/port/unix_latch.c
index 65b2fc56e03..343bf5e536b 100644
--- a/src/backend/port/unix_latch.c
+++ b/src/backend/port/unix_latch.c
@@ -60,11 +60,41 @@ static volatile sig_atomic_t waiting = false;
 static int	selfpipe_readfd = -1;
 static int	selfpipe_writefd = -1;
 
-/* private function prototypes */
-static void initSelfPipe(void);
-static void drainSelfPipe(void);
+/* Private function prototypes */
 static void sendSelfPipeByte(void);
+static void drainSelfPipe(void);
+
+
+/*
+ * Initialize the process-local latch infrastructure.
+ *
+ * This must be called once during startup of any process that can wait on
+ * latches, before it issues any InitLatch() or OwnLatch() calls.
+ */
+void
+InitializeLatchSupport(void)
+{
+	int			pipefd[2];
+
+	Assert(selfpipe_readfd == -1);
+
+	/*
+	 * Set up the self-pipe that allows a signal handler to wake up the
+	 * select() in WaitLatch. Make the write-end non-blocking, so that
+	 * SetLatch won't block if the event has already been set many times
+	 * filling the kernel buffer. Make the read-end non-blocking too, so that
+	 * we can easily clear the pipe by reading until EAGAIN or EWOULDBLOCK.
+	 */
+	if (pipe(pipefd) < 0)
+		elog(FATAL, "pipe() failed: %m");
+	if (fcntl(pipefd[0], F_SETFL, O_NONBLOCK) < 0)
+		elog(FATAL, "fcntl() failed on read-end of self-pipe: %m");
+	if (fcntl(pipefd[1], F_SETFL, O_NONBLOCK) < 0)
+		elog(FATAL, "fcntl() failed on write-end of self-pipe: %m");
 
+	selfpipe_readfd = pipefd[0];
+	selfpipe_writefd = pipefd[1];
+}
 
 /*
  * Initialize a backend-local latch.
@@ -72,9 +102,8 @@ static void sendSelfPipeByte(void);
 void
 InitLatch(volatile Latch *latch)
 {
-	/* Initialize the self-pipe if this is our first latch in the process */
-	if (selfpipe_readfd == -1)
-		initSelfPipe();
+	/* Assert InitializeLatchSupport has been called in this process */
+	Assert(selfpipe_readfd >= 0);
 
 	latch->is_set = false;
 	latch->owner_pid = MyProcPid;
@@ -116,11 +145,10 @@ InitSharedLatch(volatile Latch *latch)
 void
 OwnLatch(volatile Latch *latch)
 {
-	Assert(latch->is_shared);
+	/* Assert InitializeLatchSupport has been called in this process */
+	Assert(selfpipe_readfd >= 0);
 
-	/* Initialize the self-pipe if this is our first latch in this process */
-	if (selfpipe_readfd == -1)
-		initSelfPipe();
+	Assert(latch->is_shared);
 
 	/* sanity check */
 	if (latch->owner_pid != 0)
@@ -511,30 +539,6 @@ latch_sigusr1_handler(void)
 		sendSelfPipeByte();
 }
 
-/* initialize the self-pipe */
-static void
-initSelfPipe(void)
-{
-	int			pipefd[2];
-
-	/*
-	 * Set up the self-pipe that allows a signal handler to wake up the
-	 * select() in WaitLatch. Make the write-end non-blocking, so that
-	 * SetLatch won't block if the event has already been set many times
-	 * filling the kernel buffer. Make the read-end non-blocking too, so that
-	 * we can easily clear the pipe by reading until EAGAIN or EWOULDBLOCK.
-	 */
-	if (pipe(pipefd) < 0)
-		elog(FATAL, "pipe() failed: %m");
-	if (fcntl(pipefd[0], F_SETFL, O_NONBLOCK) < 0)
-		elog(FATAL, "fcntl() failed on read-end of self-pipe: %m");
-	if (fcntl(pipefd[1], F_SETFL, O_NONBLOCK) < 0)
-		elog(FATAL, "fcntl() failed on write-end of self-pipe: %m");
-
-	selfpipe_readfd = pipefd[0];
-	selfpipe_writefd = pipefd[1];
-}
-
 /* Send one byte to the self-pipe, to wake up WaitLatch */
 static void
 sendSelfPipeByte(void)
diff --git a/src/backend/port/win32_latch.c b/src/backend/port/win32_latch.c
index eb46dcad1ba..eaa30c4a501 100644
--- a/src/backend/port/win32_latch.c
+++ b/src/backend/port/win32_latch.c
@@ -31,6 +31,12 @@
 
 
 void
+InitializeLatchSupport(void)
+{
+	/* currently, nothing to do here for Windows */
+}
+
+void
 InitLatch(volatile Latch *latch)
 {
 	latch->is_set = false;
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.c
index 5c43cdde653..d87618f7621 100644
--- a/src/backend/postmaster/pgarch.c
+++ b/src/backend/postmaster/pgarch.c
@@ -234,8 +234,6 @@ PgArchiverMain(int argc, char *argv[])
 
 	MyProcPid = getpid();		/* reset MyProcPid */
 
-	InitLatch(&mainloop_latch); /* initialize latch used in main loop */
-
 	MyStartTime = time(NULL);	/* record Start Time for logging */
 
 	/*
@@ -247,6 +245,10 @@ PgArchiverMain(int argc, char *argv[])
 		elog(FATAL, "setsid() failed: %m");
 #endif
 
+	InitializeLatchSupport();		/* needed for latch waits */
+
+	InitLatch(&mainloop_latch); /* initialize latch used in main loop */
+
 	/*
 	 * Ignore all signals usually bound to some action in the postmaster,
 	 * except for SIGHUP, SIGTERM, SIGUSR1, SIGUSR2, and SIGQUIT.
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c
index 73d5b2e39c8..7684e11a9ae 100644
--- a/src/backend/postmaster/pgstat.c
+++ b/src/backend/postmaster/pgstat.c
@@ -3021,6 +3021,8 @@ PgstatCollectorMain(int argc, char *argv[])
 		elog(FATAL, "setsid() failed: %m");
 #endif
 
+	InitializeLatchSupport();		/* needed for latch waits */
+
 	/* Initialize private latch for use by signal handlers */
 	InitLatch(&pgStatLatch);
 
diff --git a/src/backend/postmaster/syslogger.c b/src/backend/postmaster/syslogger.c
index 98e0bfbf615..eeba40b928a 100644
--- a/src/backend/postmaster/syslogger.c
+++ b/src/backend/postmaster/syslogger.c
@@ -250,6 +250,8 @@ SysLoggerMain(int argc, char *argv[])
 		elog(FATAL, "setsid() failed: %m");
 #endif
 
+	InitializeLatchSupport();		/* needed for latch waits */
+
 	/* Initialize private latch for use by signal handlers */
 	InitLatch(&sysLoggerLatch);
 
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c
index 8593713e78f..1dda2f81c30 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -292,6 +292,13 @@ InitProcess(void)
 		elog(ERROR, "you already exist");
 
 	/*
+	 * Initialize process-local latch support.  This could fail if the kernel
+	 * is low on resources, and if so we want to exit cleanly before acquiring
+	 * any shared-memory resources.
+	 */
+	InitializeLatchSupport();
+
+	/*
 	 * Try to get a proc struct from the free list.  If this fails, we must be
 	 * out of PGPROC structures (not to mention semaphores).
 	 *
@@ -465,6 +472,13 @@ InitAuxiliaryProcess(void)
 		elog(ERROR, "you already exist");
 
 	/*
+	 * Initialize process-local latch support.  This could fail if the kernel
+	 * is low on resources, and if so we want to exit cleanly before acquiring
+	 * any shared-memory resources.
+	 */
+	InitializeLatchSupport();
+
+	/*
 	 * We use the ProcStructLock to protect assignment and releasing of
 	 * AuxiliaryProcs entries.
 	 *