diff options
| -rw-r--r-- | src/backend/port/unix_latch.c | 72 | ||||
| -rw-r--r-- | src/backend/port/win32_latch.c | 6 | ||||
| -rw-r--r-- | src/backend/storage/lmgr/proc.c | 14 | ||||
| -rw-r--r-- | src/include/storage/latch.h | 1 |
4 files changed, 59 insertions, 34 deletions
diff --git a/src/backend/port/unix_latch.c b/src/backend/port/unix_latch.c index 19bb7def1f7..caedafe7c0e 100644 --- a/src/backend/port/unix_latch.c +++ b/src/backend/port/unix_latch.c @@ -49,11 +49,41 @@ 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. @@ -61,9 +91,8 @@ 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; @@ -105,11 +134,10 @@ 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) @@ -356,30 +384,6 @@ 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 bd9c9faf9e5..36991533927 100644 --- a/src/backend/port/win32_latch.c +++ b/src/backend/port/win32_latch.c @@ -29,6 +29,12 @@ void +InitializeLatchSupport(void) +{ + /* currently, nothing to do here for Windows */ +} + +void InitLatch(volatile Latch *latch) { latch->is_set = false; diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 2d423ffebff..1cabefcea2c 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -260,6 +260,13 @@ 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). * @@ -425,6 +432,13 @@ 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. * diff --git a/src/include/storage/latch.h b/src/include/storage/latch.h index 4da28566a68..17aafbb359d 100644 --- a/src/include/storage/latch.h +++ b/src/include/storage/latch.h @@ -94,6 +94,7 @@ typedef struct /* * prototypes for functions in latch.c */ +extern void InitializeLatchSupport(void); extern void InitLatch(volatile Latch *latch); extern void InitSharedLatch(volatile Latch *latch); extern void OwnLatch(volatile Latch *latch); |