From 85af0b803cd19a03f71bd01ab4e045552410368f Mon Sep 17 00:00:00 2001 From: Michal Privoznik Date: Sat, 11 Mar 2017 07:23:42 +0100 Subject: [PATCH] qemu: Adaptive timeout for connecting to monitor There were couple of reports on the list (e.g. [1]) that guests with huge amounts of RAM are unable to start because libvirt kills qemu in the initialization phase. The problem is that if guest is configured to use hugepages kernel has to zero them all out before handing over to qemu process. For instance, 402GiB worth of 1GiB pages took around 105 seconds (~3.8GiB/s). Since we do not want to make the timeout for connecting to monitor configurable, we have to teach libvirt to count with this fact. This commit implements "1s per each 1GiB of RAM" approach as suggested here [2]. 1: https://www.redhat.com/archives/libvir-list/2017-March/msg00373.html 2: https://www.redhat.com/archives/libvir-list/2017-March/msg00405.html Signed-off-by: Michal Privoznik --- src/qemu/qemu_capabilities.c | 2 +- src/qemu/qemu_monitor.c | 36 +++++++++++++++++++++++++++++++----- src/qemu/qemu_monitor.h | 1 + src/qemu/qemu_process.c | 8 ++++++++ tests/qemumonitortestutils.c | 1 + 5 files changed, 42 insertions(+), 6 deletions(-) diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index da03ff4c61..5200b39a3f 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -4767,7 +4767,7 @@ virQEMUCapsInitQMPCommandRun(virQEMUCapsInitQMPCommandPtr cmd, cmd->vm->pid = cmd->pid; if (!(cmd->mon = qemuMonitorOpen(cmd->vm, &cmd->config, true, - &callbacks, NULL))) + 0, &callbacks, NULL))) goto ignore; virObjectLock(cmd->mon); diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c index d71f84c800..066d3444bb 100644 --- a/src/qemu/qemu_monitor.c +++ b/src/qemu/qemu_monitor.c @@ -327,11 +327,13 @@ qemuMonitorDispose(void *obj) static int -qemuMonitorOpenUnix(const char *monitor, pid_t cpid) +qemuMonitorOpenUnix(const char *monitor, + pid_t cpid, + unsigned long long timeout) { struct sockaddr_un addr; int monfd; - virTimeBackOffVar timeout; + virTimeBackOffVar timebackoff; int ret = -1; if ((monfd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0) { @@ -348,9 +350,9 @@ qemuMonitorOpenUnix(const char *monitor, pid_t cpid) goto error; } - if (virTimeBackOffStart(&timeout, 1, 30*1000 /* ms */) < 0) + if (virTimeBackOffStart(&timebackoff, 1, timeout * 1000) < 0) goto error; - while (virTimeBackOffWait(&timeout)) { + while (virTimeBackOffWait(&timebackoff)) { ret = connect(monfd, (struct sockaddr *) &addr, sizeof(addr)); if (ret == 0) @@ -871,10 +873,30 @@ qemuMonitorOpenInternal(virDomainObjPtr vm, } +#define QEMU_DEFAULT_MONITOR_WAIT 30 + +/** + * qemuMonitorOpen: + * @vm: domain object + * @config: monitor configuration + * @json: enable JSON on the monitor + * @timeout: number of seconds to add to default timeout + * @cb: monitor event handles + * @opaque: opaque data for @cb + * + * Opens the monitor for running qemu. It may happen that it + * takes some time for qemu to create the monitor socket (e.g. + * because kernel is zeroing configured hugepages), therefore we + * wait up to default + timeout seconds for the monitor to show + * up after which a failure is claimed. + * + * Returns monitor object, NULL on error. + */ qemuMonitorPtr qemuMonitorOpen(virDomainObjPtr vm, virDomainChrSourceDefPtr config, bool json, + unsigned long long timeout, qemuMonitorCallbacksPtr cb, void *opaque) { @@ -882,10 +904,14 @@ qemuMonitorOpen(virDomainObjPtr vm, bool hasSendFD = false; qemuMonitorPtr ret; + timeout += QEMU_DEFAULT_MONITOR_WAIT; + switch (config->type) { case VIR_DOMAIN_CHR_TYPE_UNIX: hasSendFD = true; - if ((fd = qemuMonitorOpenUnix(config->data.nix.path, vm ? vm->pid : 0)) < 0) + if ((fd = qemuMonitorOpenUnix(config->data.nix.path, + vm ? vm->pid : 0, + timeout)) < 0) return NULL; break; diff --git a/src/qemu/qemu_monitor.h b/src/qemu/qemu_monitor.h index 847e9458a5..3c37a6ffe3 100644 --- a/src/qemu/qemu_monitor.h +++ b/src/qemu/qemu_monitor.h @@ -246,6 +246,7 @@ char *qemuMonitorUnescapeArg(const char *in); qemuMonitorPtr qemuMonitorOpen(virDomainObjPtr vm, virDomainChrSourceDefPtr config, bool json, + unsigned long long timeout, qemuMonitorCallbacksPtr cb, void *opaque) ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_NONNULL(4); diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index b9c1847bba..7397f59c7a 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -1658,6 +1658,7 @@ qemuConnectMonitor(virQEMUDriverPtr driver, virDomainObjPtr vm, int asyncJob, qemuDomainObjPrivatePtr priv = vm->privateData; int ret = -1; qemuMonitorPtr mon = NULL; + unsigned long long timeout = 0; if (qemuSecuritySetDaemonSocketLabel(driver->securityManager, vm->def) < 0) { VIR_ERROR(_("Failed to set security context for monitor for %s"), @@ -1665,6 +1666,12 @@ qemuConnectMonitor(virQEMUDriverPtr driver, virDomainObjPtr vm, int asyncJob, return -1; } + /* When using hugepages, kernel zeroes them out before + * handing them over to qemu. This can be very time + * consuming. Therefore, add a second to timeout for each + * 1GiB of guest RAM. */ + timeout = vm->def->mem.total_memory / (1024 * 1024); + /* Hold an extra reference because we can't allow 'vm' to be * deleted until the monitor gets its own reference. */ virObjectRef(vm); @@ -1675,6 +1682,7 @@ qemuConnectMonitor(virQEMUDriverPtr driver, virDomainObjPtr vm, int asyncJob, mon = qemuMonitorOpen(vm, priv->monConfig, priv->monJSON, + timeout, &monitorCallbacks, driver); diff --git a/tests/qemumonitortestutils.c b/tests/qemumonitortestutils.c index cfd0a38cbb..89857a6620 100644 --- a/tests/qemumonitortestutils.c +++ b/tests/qemumonitortestutils.c @@ -1175,6 +1175,7 @@ qemuMonitorTestNew(bool json, if (!(test->mon = qemuMonitorOpen(test->vm, &src, json, + 0, &qemuMonitorTestCallbacks, driver))) goto error; -- 2.39.5