This is an automated email from the ASF dual-hosted git repository. reshke pushed a commit to branch address_1566_p2 in repository https://gitbox.apache.org/repos/asf/cloudberry.git
commit cbf9091fa4c39f1922884f9065b37a01bb0887f8 Author: Thomas Munro <[email protected]> AuthorDate: Sun Jun 26 10:40:06 2022 +1200 Don't trust signalfd() on illumos. Since commit 6a2a70a02, we've used signalfd() to receive latch wakeups when building with WAIT_USE_EPOLL (default for Linux and illumos), and our traditional self-pipe when falling back to WAIT_USE_POLL (default for other Unixes with neither epoll() nor kqueue()). Unexplained hangs and kernel panics have been reported on illumos systems, apparently linked to this use of signalfd(), leading illumos users and build farm members to have to define WAIT_USE_POLL explicitly as a work-around. A bug report exists at https://www.illumos.org/issues/13700 but no fix is available yet. Let's provide a way for illumos users to go back to self-pipes with epoll(), like releases before 14, and choose that by default. No change for Linux users. To help with development/debugging, macros WAIT_USE_{EPOLL,POLL} and WAIT_USE_{SIGNALFD,SELF_PIPE} can be defined explicitly to override the defaults. Back-patch to 14, where we started using signalfd(). Reported-by: Japin Li <[email protected]> Reported-by: Olaf Bohlen <[email protected]> (off-list) Reviewed-by: Japin Li <[email protected]> Discussion: https://postgr.es/m/MEYP282MB1669C8D88F0997354C2313C1B6CA9%40MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM --- src/backend/storage/ipc/latch.c | 58 ++++++++++++++++++++++++++++------------- 1 file changed, 40 insertions(+), 18 deletions(-) diff --git a/src/backend/storage/ipc/latch.c b/src/backend/storage/ipc/latch.c index e81041ae029..7ecd3afe1b9 100644 --- a/src/backend/storage/ipc/latch.c +++ b/src/backend/storage/ipc/latch.c @@ -72,7 +72,7 @@ #if defined(WAIT_USE_EPOLL) || defined(WAIT_USE_POLL) || \ defined(WAIT_USE_KQUEUE) || defined(WAIT_USE_WIN32) /* don't overwrite manual choice */ -#elif defined(HAVE_SYS_EPOLL_H) && defined(HAVE_SYS_SIGNALFD_H) +#elif defined(HAVE_SYS_EPOLL_H) #define WAIT_USE_EPOLL #elif defined(HAVE_KQUEUE) #define WAIT_USE_KQUEUE @@ -84,6 +84,22 @@ #error "no wait set implementation available" #endif +/* + * By default, we use a self-pipe with poll() and a signalfd with epoll(), if + * available. We avoid signalfd on illumos for now based on problem reports. + * For testing the choice can also be manually specified. + */ +#if defined(WAIT_USE_POLL) || defined(WAIT_USE_EPOLL) +#if defined(WAIT_USE_SELF_PIPE) || defined(WAIT_USE_SIGNALFD) +/* don't overwrite manual choice */ +#elif defined(WAIT_USE_EPOLL) && defined(HAVE_SYS_SIGNALFD_H) && \ + !defined(__illumos__) +#define WAIT_USE_SIGNALFD +#else +#define WAIT_USE_SELF_PIPE +#endif +#endif + /* typedef in latch.h */ struct WaitEventSet { @@ -146,12 +162,12 @@ static WaitEventSet *LatchWaitSet; static volatile sig_atomic_t waiting = false; #endif -#ifdef WAIT_USE_EPOLL +#ifdef WAIT_USE_SIGNALFD /* On Linux, we'll receive SIGURG via a signalfd file descriptor. */ static int signal_fd = -1; #endif -#if defined(WAIT_USE_POLL) +#ifdef WAIT_USE_SELF_PIPE /* Read and write ends of the self-pipe */ static int selfpipe_readfd = -1; static int selfpipe_writefd = -1; @@ -164,7 +180,7 @@ static void latch_sigurg_handler(SIGNAL_ARGS); static void sendSelfPipeByte(void); #endif -#if defined(WAIT_USE_POLL) || defined(WAIT_USE_EPOLL) +#if defined(WAIT_USE_SELF_PIPE) || defined(WAIT_USE_SIGNALFD) static void drain(void); #endif @@ -190,7 +206,7 @@ static inline int WaitEventSetWaitBlock(WaitEventSet *set, int cur_timeout, void InitializeLatchSupport(void) { -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) int pipefd[2]; if (IsUnderPostmaster) @@ -264,7 +280,7 @@ InitializeLatchSupport(void) pqsignal(SIGURG, latch_sigurg_handler); #endif -#ifdef WAIT_USE_EPOLL +#ifdef WAIT_USE_SIGNALFD sigset_t signalfd_mask; /* Block SIGURG, because we'll receive it through a signalfd. */ @@ -316,7 +332,7 @@ ShutdownLatchSupport(void) LatchWaitSet = NULL; } -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) close(selfpipe_readfd); close(selfpipe_writefd); selfpipe_readfd = -1; @@ -324,7 +340,7 @@ ShutdownLatchSupport(void) selfpipe_owner_pid = InvalidPid; #endif -#if defined(WAIT_USE_EPOLL) +#if defined(WAIT_USE_SIGNALFD) close(signal_fd); signal_fd = -1; #endif @@ -341,9 +357,12 @@ InitLatch(Latch *latch) latch->owner_pid = MyProcPid; latch->is_shared = false; -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) /* Assert InitializeLatchSupport has been called in this process */ Assert(selfpipe_readfd >= 0 && selfpipe_owner_pid == MyProcPid); +#elif defined(WAIT_USE_SIGNALFD) + /* Assert InitializeLatchSupport has been called in this process */ + Assert(signal_fd >= 0); #elif defined(WAIT_USE_WIN32) latch->event = CreateEvent(NULL, TRUE, FALSE, NULL); if (latch->event == NULL) @@ -405,9 +424,12 @@ OwnLatch(Latch *latch) /* Sanity checks */ Assert(latch->is_shared); -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) /* Assert InitializeLatchSupport has been called in this process */ Assert(selfpipe_readfd >= 0 && selfpipe_owner_pid == MyProcPid); +#elif defined(WAIT_USE_SIGNALFD) + /* Assert InitializeLatchSupport has been called in this process */ + Assert(signal_fd >= 0); #endif if (latch->owner_pid != 0) @@ -618,7 +640,7 @@ SetLatch(Latch *latch) return; else if (owner_pid == MyProcPid) { -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) if (waiting) sendSelfPipeByte(); #else @@ -983,9 +1005,9 @@ AddWaitEventToSet(WaitEventSet *set, uint32 events, pgsocket fd, Latch *latch, { set->latch = latch; set->latch_pos = event->pos; -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) event->fd = selfpipe_readfd; -#elif defined(WAIT_USE_EPOLL) +#elif defined(WAIT_USE_SIGNALFD) event->fd = signal_fd; #else event->fd = PGINVALID_SOCKET; @@ -2102,7 +2124,7 @@ GetNumRegisteredWaitEvents(WaitEventSet *set) return set->nevents; } -#if defined(WAIT_USE_POLL) +#if defined(WAIT_USE_SELF_PIPE) /* * SetLatch uses SIGURG to wake up the process waiting on the latch. @@ -2153,7 +2175,7 @@ retry: #endif -#if defined(WAIT_USE_POLL) || defined(WAIT_USE_EPOLL) +#if defined(WAIT_USE_SELF_PIPE) || defined(WAIT_USE_SIGNALFD) /* * Read all available data from self-pipe or signalfd. @@ -2169,7 +2191,7 @@ drain(void) int rc; int fd; -#ifdef WAIT_USE_POLL +#ifdef WAIT_USE_SELF_PIPE fd = selfpipe_readfd; #else fd = signal_fd; @@ -2187,7 +2209,7 @@ drain(void) else { waiting = false; -#ifdef WAIT_USE_POLL +#ifdef WAIT_USE_SELF_PIPE elog(ERROR, "read() on self-pipe failed: %m"); #else elog(ERROR, "read() on signalfd failed: %m"); @@ -2197,7 +2219,7 @@ drain(void) else if (rc == 0) { waiting = false; -#ifdef WAIT_USE_POLL +#ifdef WAIT_USE_SELF_PIPE elog(ERROR, "unexpected EOF on self-pipe"); #else elog(ERROR, "unexpected EOF on signalfd"); --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
