[libvirt] [PATCH] lxc: suspend/resume support
Ryota Ozaki
ozaki.ryota at gmail.com
Wed Sep 16 15:42:08 UTC 2009
Hi
I've updated the patch with Chris' suggestions.
The change includes
- not wait for long period in the case that the freezing
is complete quickly without increasing the number of polling
in the case the freezing is slow or never complete
- add event notifications
Thanks,
ozaki-r
>From 843d989cf1584e7622bd82a023241a9b333deee2 Mon Sep 17 00:00:00 2001
From: Ryota Ozaki <ozaki.ryota at gmail.com>
Date: Thu, 17 Sep 2009 00:26:24 +0900
Subject: [PATCH] lxc: suspend/resume support
---
src/cgroup.c | 23 ++++++-
src/cgroup.h | 4 +
src/domain_conf.c | 27 ++++---
src/lxc_driver.c | 212 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
4 files changed, 251 insertions(+), 15 deletions(-)
diff --git a/src/cgroup.c b/src/cgroup.c
index 111601d..2e646fd 100644
--- a/src/cgroup.c
+++ b/src/cgroup.c
@@ -32,7 +32,8 @@
#define CGROUP_MAX_VAL 512
VIR_ENUM_IMPL(virCgroupController, VIR_CGROUP_CONTROLLER_LAST,
- "cpu", "cpuacct", "cpuset", "memory", "devices");
+ "cpu", "cpuacct", "cpuset", "memory", "devices",
+ "freezer");
struct virCgroupController {
int type;
@@ -896,3 +897,23 @@ int virCgroupGetCpuacctUsage(virCgroupPtr group,
unsigned long long *usage)
VIR_CGROUP_CONTROLLER_CPUACCT,
"cpuacct.usage", (uint64_t *)usage);
}
+
+int virCgroupSetFreezerState(virCgroupPtr group, const char *state)
+{
+ return virCgroupSetValueStr(group,
+ VIR_CGROUP_CONTROLLER_CPU,
+ "freezer.state", state);
+}
+
+int virCgroupGetFreezerState(virCgroupPtr group, char **state)
+{
+ int ret;
+ ret = virCgroupGetValueStr(group,
+ VIR_CGROUP_CONTROLLER_CPU,
+ "freezer.state", state);
+ if (ret == 0) {
+ char *p = strchr(*state, '¥n');
+ if (p) *p = '¥0';
+ }
+ return ret;
+}
diff --git a/src/cgroup.h b/src/cgroup.h
index 6d43b14..aba56c6 100644
--- a/src/cgroup.h
+++ b/src/cgroup.h
@@ -21,6 +21,7 @@ enum {
VIR_CGROUP_CONTROLLER_CPUSET,
VIR_CGROUP_CONTROLLER_MEMORY,
VIR_CGROUP_CONTROLLER_DEVICES,
+ VIR_CGROUP_CONTROLLER_FREEZER,
VIR_CGROUP_CONTROLLER_LAST
};
@@ -68,6 +69,9 @@ int virCgroupGetCpuShares(virCgroupPtr group,
unsigned long long *shares);
int virCgroupGetCpuacctUsage(virCgroupPtr group, unsigned long long *usage);
+int virCgroupSetFreezerState(virCgroupPtr group, const char *state);
+int virCgroupGetFreezerState(virCgroupPtr group, char **state);
+
int virCgroupRemove(virCgroupPtr group);
void virCgroupFree(virCgroupPtr *group);
diff --git a/src/domain_conf.c b/src/domain_conf.c
index 5ae0775..5e37d96 100644
--- a/src/domain_conf.c
+++ b/src/domain_conf.c
@@ -4433,19 +4433,22 @@ char *virDomainObjFormat(virConnectPtr conn,
virDomainStateTypeToString(obj->state),
obj->pid);
- switch (obj->monitor_chr->type) {
- case VIR_DOMAIN_CHR_TYPE_UNIX:
- monitorpath = obj->monitor_chr->data.nix.path;
- break;
- default:
- case VIR_DOMAIN_CHR_TYPE_PTY:
- monitorpath = obj->monitor_chr->data.file.path;
- break;
- }
+ /* obj->monitor_chr is set only for qemu */
+ if (obj->monitor_chr) {
+ switch (obj->monitor_chr->type) {
+ case VIR_DOMAIN_CHR_TYPE_UNIX:
+ monitorpath = obj->monitor_chr->data.nix.path;
+ break;
+ default:
+ case VIR_DOMAIN_CHR_TYPE_PTY:
+ monitorpath = obj->monitor_chr->data.file.path;
+ break;
+ }
- virBufferEscapeString(&buf, " <monitor path='%s'", monitorpath);
- virBufferVSprintf(&buf, " type='%s'/>¥n",
- virDomainChrTypeToString(obj->monitor_chr->type));
+ virBufferEscapeString(&buf, " <monitor path='%s'", monitorpath);
+ virBufferVSprintf(&buf, " type='%s'/>¥n",
+ virDomainChrTypeToString(obj->monitor_chr->type));
+ }
if (obj->nvcpupids) {
diff --git a/src/lxc_driver.c b/src/lxc_driver.c
index 0ec1e92..e4825b4 100644
--- a/src/lxc_driver.c
+++ b/src/lxc_driver.c
@@ -1862,6 +1862,214 @@ static char *lxcGetHostname (virConnectPtr conn)
return result;
}
+static int lxcFreezeContainer(lxc_driver_t *driver, virDomainObjPtr vm)
+{
+ int timeout = 1000; /* In milliseconds */
+ int check_interval = 1; /* In milliseconds */
+ int exp = 10;
+ int waited_time = 0;
+ int ret = -1;
+ char *state = NULL;
+ virCgroupPtr cgroup = NULL;
+
+ if (!(driver->cgroup &&
+ virCgroupForDomain(driver->cgroup, vm->def->name, &cgroup, 0) == 0))
+ return -1;
+
+ while (waited_time < timeout) {
+ int r;
+ /*
+ * Writing "FROZEN" to the "freezer.state" freezes the group,
+ * i.e., the container, temporarily transiting "FREEZING" state.
+ * Once the freezing is completed, the state of the group transits
+ * to "FROZEN".
+ * (see linux-2.6/Documentation/cgroups/freezer-subsystem.txt)
+ */
+ r = virCgroupSetFreezerState(cgroup, "FROZEN");
+
+ /*
+ * Returning EBUSY explicitly indicates that the group is
+ * being freezed but incomplete and other errors are true
+ * errors.
+ */
+ if (r < 0 && r != -EBUSY) {
+ VIR_DEBUG("Writing freezer.state failed with errno: %d", r);
+ goto error;
+ }
+ if (r == -EBUSY)
+ VIR_DEBUG0("Writing freezer.state gets EBUSY");
+
+ /*
+ * Unfortunately, returning 0 (success) is likely to happen
+ * even when the freezing has not been completed. Sometimes
+ * the state of the group remains "FREEZING" like when
+ * returning -EBUSY and even worse may never transit to
+ * "FROZEN" even if writing "FROZEN" again.
+ *
+ * So we don't trust the return value anyway and always
+ * decide that the freezing has been complete only with
+ * the state actually transit to "FROZEN".
+ */
+ usleep(check_interval * 1000);
+
+ r = virCgroupGetFreezerState(cgroup, &state);
+
+ if (r < 0) {
+ VIR_DEBUG("Reading freezer.state failed with errno: %d", r);
+ goto error;
+ }
+ VIR_DEBUG("Read freezer.state: %s", state);
+
+ if (STREQ(state, "FROZEN")) {
+ ret = 0;
+ goto cleanup;
+ }
+
+ waited_time += check_interval;
+ /*
+ * Increasing check_interval exponentially starting with
+ * small initial value treats nicely two cases; One is
+ * a container is under no load and waiting for long period
+ * makes no sense. The other is under heavy load. The container
+ * may stay longer time in FREEZING or never transit to FROZEN.
+ * In that case, eager polling will just waste CPU time.
+ */
+ check_interval *= exp;
+ VIR_FREE(state);
+ }
+ VIR_DEBUG0("lxcFreezeContainer timeout");
+error:
+ /*
+ * If timeout or an error on reading the state occurs,
+ * activate the group again and return an error.
+ * This is likely to fall the group back again gracefully.
+ */
+ virCgroupSetFreezerState(cgroup, "THAWED");
+ ret = -1;
+
+cleanup:
+ if (cgroup)
+ virCgroupFree(&cgroup);
+ VIR_FREE(state);
+ return ret;
+}
+
+static int lxcDomainSuspend(virDomainPtr dom)
+{
+ lxc_driver_t *driver = dom->conn->privateData;
+ virDomainObjPtr vm;
+ virDomainEventPtr event = NULL;
+ int ret = -1;
+
+ lxcDriverLock(driver);
+ vm = virDomainFindByUUID(&driver->domains, dom->uuid);
+
+ if (!vm) {
+ char uuidstr[VIR_UUID_STRING_BUFLEN];
+ virUUIDFormat(dom->uuid, uuidstr);
+ lxcError(dom->conn, dom, VIR_ERR_NO_DOMAIN,
+ _("no domain with matching uuid '%s'"), uuidstr);
+ goto cleanup;
+ }
+
+ if (!virDomainIsActive(vm)) {
+ lxcError(dom->conn, dom, VIR_ERR_OPERATION_INVALID,
+ "%s", _("domain is not running"));
+ goto cleanup;
+ }
+
+ if (vm->state != VIR_DOMAIN_PAUSED) {
+ if (lxcFreezeContainer(driver, vm) < 0) {
+ lxcError(dom->conn, dom, VIR_ERR_OPERATION_FAILED,
+ "%s", _("suspend operation failed"));
+ goto cleanup;
+ }
+ vm->state = VIR_DOMAIN_PAUSED;
+ }
+
+ if (virDomainSaveStatus(dom->conn, driver->stateDir, vm) < 0)
+ goto cleanup;
+ ret = 0;
+
+ event = virDomainEventNewFromObj(vm,
+ VIR_DOMAIN_EVENT_SUSPENDED,
+ VIR_DOMAIN_EVENT_SUSPENDED_PAUSED);
+
+cleanup:
+ if (event)
+ lxcDomainEventQueue(driver, event);
+ if (vm)
+ virDomainObjUnlock(vm);
+ lxcDriverUnlock(driver);
+ return ret;
+}
+
+static int lxcUnfreezeContainer(lxc_driver_t *driver, virDomainObjPtr vm)
+{
+ int ret;
+ virCgroupPtr cgroup = NULL;
+
+ if (!(driver->cgroup &&
+ virCgroupForDomain(driver->cgroup, vm->def->name, &cgroup, 0) == 0))
+ return -1;
+
+ ret = virCgroupSetFreezerState(cgroup, "THAWED");
+
+ virCgroupFree(&cgroup);
+ return ret;
+}
+
+static int lxcDomainResume(virDomainPtr dom)
+{
+ lxc_driver_t *driver = dom->conn->privateData;
+ virDomainObjPtr vm;
+ virDomainEventPtr event = NULL;
+ int ret = -1;
+
+ lxcDriverLock(driver);
+ vm = virDomainFindByUUID(&driver->domains, dom->uuid);
+
+ if (!vm) {
+ char uuidstr[VIR_UUID_STRING_BUFLEN];
+ virUUIDFormat(dom->uuid, uuidstr);
+ lxcError(dom->conn, dom, VIR_ERR_NO_DOMAIN,
+ _("no domain with matching uuid '%s'"), uuidstr);
+ goto cleanup;
+ }
+
+ if (!virDomainIsActive(vm)) {
+ lxcError(dom->conn, dom, VIR_ERR_OPERATION_INVALID,
+ "%s", _("domain is not running"));
+ goto cleanup;
+ }
+
+ if (vm->state == VIR_DOMAIN_PAUSED) {
+ if (lxcUnfreezeContainer(driver, vm) < 0) {
+ lxcError(dom->conn, dom, VIR_ERR_OPERATION_FAILED,
+ "%s", _("resume operation failed"));
+ goto cleanup;
+ }
+ vm->state = VIR_DOMAIN_RUNNING;
+ }
+
+ if (virDomainSaveStatus(dom->conn, driver->stateDir, vm) < 0)
+ goto cleanup;
+ ret = 0;
+
+ event = virDomainEventNewFromObj(vm,
+ VIR_DOMAIN_EVENT_RESUMED,
+ VIR_DOMAIN_EVENT_RESUMED_UNPAUSED);
+
+cleanup:
+ if (event)
+ lxcDomainEventQueue(driver, event);
+ if (vm)
+ virDomainObjUnlock(vm);
+ lxcDriverUnlock(driver);
+ return ret;
+}
+
+
/* Function Tables */
static virDriver lxcDriver = {
VIR_DRV_LXC, /* the number virDrvNo */
@@ -1881,8 +2089,8 @@ static virDriver lxcDriver = {
lxcDomainLookupByID, /* domainLookupByID */
lxcDomainLookupByUUID, /* domainLookupByUUID */
lxcDomainLookupByName, /* domainLookupByName */
- NULL, /* domainSuspend */
- NULL, /* domainResume */
+ lxcDomainSuspend, /* domainSuspend */
+ lxcDomainResume, /* domainResume */
lxcDomainShutdown, /* domainShutdown */
NULL, /* domainReboot */
lxcDomainDestroy, /* domainDestroy */
--
1.6.0.6
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