This commit tries to fix lots of issues related to LXC VCPUs. One of
them is related to /proc/cpuinfo content. If only 1 VCPU is set, LXC
containers will show all CPUs available for host. The second one is
related to CPU share, if an user set only 1 VCPU, the container/process
will use all available CPUs. (This is not the case when `cpuset`
attribute is declared). So, this commit adds a virtual cpuinfo based on
VCPU mapping and it automatically limits the CPU usage according VCPU
count.
Example (now):
LXC container - 8 CPUS with 2 VCPU:
lxc-root# stress --cpu 8
On host machine, only CPU 0 and 1 have 100% usage.
Signed-off-by: Julio Faracco <jcfaracco@xxxxxxxxx>
---
src/lxc/lxc_cgroup.c | 31 ++++++++++++++
src/lxc/lxc_container.c | 39 ++++++++++-------
src/lxc/lxc_fuse.c | 95 ++++++++++++++++++++++++++++++++++++++---
3 files changed, 145 insertions(+), 20 deletions(-)
diff --git a/src/lxc/lxc_cgroup.c b/src/lxc/lxc_cgroup.c
index d29b65092a..912a252473 100644
--- a/src/lxc/lxc_cgroup.c
+++ b/src/lxc/lxc_cgroup.c
@@ -50,6 +50,34 @@ static int virLXCCgroupSetupCpuTune(virDomainDefPtr def,
}
+static int virLXCCgroupSetupVcpuAuto(virDomainDefPtr def,
+ virCgroupPtr cgroup)
+{
+ size_t i;
+ int vcpumax;
+ virBuffer buffer = VIR_BUFFER_INITIALIZER;
+ virBufferPtr cpuset = &buffer;
+
+ vcpumax = virDomainDefGetVcpusMax(def);
+ for (i = 0; i < vcpumax; i++) {
+ virDomainVcpuDefPtr vcpu = virDomainDefGetVcpu(def, i);
+ /* Cgroup is smart enough to convert numbers separated
+ * by comma into ranges. Example: "0,1,2,5," -> "0-2,5".
+ * Libvirt does not need to process it here. */
+ if (vcpu)
+ virBufferAsprintf(cpuset, "%zu,", i);
+ }
+ if (virCgroupSetCpusetCpus(cgroup,
+ virBufferCurrentContent(cpuset)) < 0) {
+ virBufferFreeAndReset(cpuset);
+ return -1;
+ }
+
+ virBufferFreeAndReset(cpuset);
+ return 0;
+}
+
+
static int virLXCCgroupSetupCpusetTune(virDomainDefPtr def,
virCgroupPtr cgroup,
virBitmapPtr nodemask)
@@ -61,6 +89,9 @@ static int virLXCCgroupSetupCpusetTune(virDomainDefPtr def,
def->cpumask &&
virCgroupSetupCpusetCpus(cgroup, def->cpumask) < 0) {
return -1;
+ } else {
+ /* auto mode for VCPU limits */
+ virLXCCgroupSetupVcpuAuto(def, cgroup);
}
if (virDomainNumatuneGetMode(def->numa, -1, &mode) < 0 ||
diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
index 41efe43a14..88e27f3060 100644
--- a/src/lxc/lxc_container.c
+++ b/src/lxc/lxc_container.c
@@ -997,8 +997,8 @@ static int lxcContainerMountBasicFS(bool userns_enabled,
static int lxcContainerMountProcFuse(virDomainDefPtr def,
const char *stateDir)
{
- int ret;
- char *meminfo_path = NULL;
+ g_autofree char *meminfo_path = NULL;
+ g_autofree char *cpuinfo_path = NULL;
VIR_DEBUG("Mount /proc/meminfo stateDir=%s", stateDir);
@@ -1006,15 +1006,29 @@ static int lxcContainerMountProcFuse(virDomainDefPtr def,
stateDir,
def->name);
- if ((ret = mount(meminfo_path, "/proc/meminfo",
- NULL, MS_BIND, NULL)) < 0) {
+ if (mount(meminfo_path, "/proc/meminfo",
+ NULL, MS_BIND, NULL) < 0) {
virReportSystemError(errno,
_("Failed to mount %s on /proc/meminfo"),
meminfo_path);
+ return -1;
}
- VIR_FREE(meminfo_path);
- return ret;
+ VIR_DEBUG("Mount /proc/cpuinfo stateDir=%s", stateDir);
+
+ cpuinfo_path = g_strdup_printf("/.oldroot/%s/%s.fuse/cpuinfo",
+ stateDir,
+ def->name);
+
+ if (mount(cpuinfo_path, "/proc/cpuinfo",
+ NULL, MS_BIND, NULL) < 0) {
+ virReportSystemError(errno,
+ _("Failed to mount %s on /proc/cpuinfo"),
+ cpuinfo_path);
+ return -1;
+ }
+
+ return 0;
}
#else
static int lxcContainerMountProcFuse(virDomainDefPtr def G_GNUC_UNUSED,
@@ -1027,8 +1041,7 @@ static int lxcContainerMountProcFuse(virDomainDefPtr def G_GNUC_UNUSED,
static int lxcContainerMountFSDev(virDomainDefPtr def,
const char *stateDir)
{
- int ret = -1;
- char *path = NULL;
+ g_autofree char *path = NULL;
int flags = def->idmap.nuidmap ? MS_BIND : MS_MOVE;
VIR_DEBUG("Mount /dev/ stateDir=%s", stateDir);
@@ -1038,7 +1051,7 @@ static int lxcContainerMountFSDev(virDomainDefPtr def,
if (virFileMakePath("/dev") < 0) {
virReportSystemError(errno, "%s",
_("Cannot create /dev"));
- goto cleanup;
+ return -1;
}
VIR_DEBUG("Trying to %s %s to /dev", def->idmap.nuidmap ?
@@ -1048,14 +1061,10 @@ static int lxcContainerMountFSDev(virDomainDefPtr def,
virReportSystemError(errno,
_("Failed to mount %s on /dev"),
path);
- goto cleanup;
+ return -1;
}
- ret = 0;
-
- cleanup:
- VIR_FREE(path);
- return ret;
+ return 0;
}
static int lxcContainerMountFSDevPTS(virDomainDefPtr def,
diff --git a/src/lxc/lxc_fuse.c b/src/lxc/lxc_fuse.c
index 8cfccdd7e0..b2117bfa17 100644
--- a/src/lxc/lxc_fuse.c
+++ b/src/lxc/lxc_fuse.c
@@ -36,23 +36,29 @@
#if WITH_FUSE
+#ifndef CPUINFO_FILE_LEN
+# define CPUINFO_FILE_LEN (1024*1024)
+#endif
+
static const char *fuse_meminfo_path = "/meminfo";
+static const char *fuse_cpuinfo_path = "/cpuinfo";
static int lxcProcGetattr(const char *path, struct stat *stbuf)
{
- g_autofree char *mempath = NULL;
+ g_autofree char *procpath = NULL;
struct stat sb;
struct fuse_context *context = fuse_get_context();
virDomainDefPtr def = (virDomainDefPtr)context->private_data;
memset(stbuf, 0, sizeof(struct stat));
- mempath = g_strdup_printf("/proc/%s", path);
+ procpath = g_strdup_printf("/proc/%s", path);
if (STREQ(path, "/")) {
stbuf->st_mode = S_IFDIR | 0755;
stbuf->st_nlink = 2;
- } else if (STREQ(path, fuse_meminfo_path)) {
- if (stat(mempath, &sb) < 0)
+ } else if (STREQ(path, fuse_meminfo_path) ||
+ STREQ(path, fuse_cpuinfo_path)) {
+ if (stat(procpath, &sb) < 0)
return -errno;
stbuf->st_uid = def->idmap.uidmap ? def->idmap.uidmap[0].target : 0;
@@ -83,6 +89,7 @@ static int lxcProcReaddir(const char *path, void *buf,
filler(buf, ".", NULL, 0);
filler(buf, "..", NULL, 0);
filler(buf, fuse_meminfo_path + 1, NULL, 0);
+ filler(buf, fuse_cpuinfo_path + 1, NULL, 0);
return 0;
}
@@ -90,7 +97,8 @@ static int lxcProcReaddir(const char *path, void *buf,
static int lxcProcOpen(const char *path G_GNUC_UNUSED,
struct fuse_file_info *fi G_GNUC_UNUSED)
{
- if (STRNEQ(path, fuse_meminfo_path))
+ if (STRNEQ(path, fuse_meminfo_path) &&
+ STRNEQ(path, fuse_cpuinfo_path))
return -ENOENT;
if ((fi->flags & 3) != O_RDONLY)
@@ -227,6 +235,80 @@ static int lxcProcReadMeminfo(char *hostpath, virDomainDefPtr def,
return res;
}
+
+static int
+lxcProcReadCpuinfoParse(virDomainDefPtr def, char *base,
+ virBufferPtr new_cpuinfo)
+{
+ char *procline = NULL;
+ char *saveptr = base;
+ size_t cpu;
+ size_t nvcpu;
+ size_t curcpu = 0;
+ bool get_proc = false;
+
+ nvcpu = virDomainDefGetVcpus(def);
+ while ((procline = strtok_r(NULL, "\n", &saveptr))) {
+ if (sscanf(procline, "processor\t: %zu", &cpu) == 1) {
+ virDomainVcpuDefPtr vcpu = virDomainDefGetVcpu(def, cpu);
+ /* VCPU is mapped */
+ if (vcpu) {
+ if (curcpu == nvcpu)
+ break;
+
+ if (curcpu > 0)
+ virBufferAddLit(new_cpuinfo, "\n");
+
+ virBufferAsprintf(new_cpuinfo, "processor\t: %zu\n",
+ curcpu);
+ curcpu++;
+ get_proc = true;
+ } else {
+ get_proc = false;
+ }
+ } else {
+ /* It is not a processor index */
+ if (get_proc)
+ virBufferAsprintf(new_cpuinfo, "%s\n", procline);
+ }
+ }
+
+ virBufferAddLit(new_cpuinfo, "\n");
+
+ return strlen(virBufferCurrentContent(new_cpuinfo));
+}
+
+
+static int lxcProcReadCpuinfo(char *hostpath, virDomainDefPtr def,
+ char *buf, size_t size, off_t offset)
+{
+ virBuffer buffer = VIR_BUFFER_INITIALIZER;
+ virBufferPtr new_cpuinfo = &buffer;
+ g_autofree char *outbuf = NULL;
+ int res = -1;
+
+ /* Gather info from /proc/cpuinfo */
+ if (virFileReadAll(hostpath, CPUINFO_FILE_LEN, &outbuf) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Failed to open %s"), hostpath);
+ return -1;
+ }
+
+ /* /proc/cpuinfo does not support fseek */
+ if (offset > 0)
+ return 0;
+
+ res = lxcProcReadCpuinfoParse(def, outbuf, new_cpuinfo);
+
+ if (res > size)
+ res = size;
+ memcpy(buf, virBufferCurrentContent(new_cpuinfo), res);
+
+ virBufferFreeAndReset(new_cpuinfo);
+ return res;
+}
+
+
static int lxcProcRead(const char *path G_GNUC_UNUSED,
char *buf G_GNUC_UNUSED,
size_t size G_GNUC_UNUSED,
@@ -246,6 +328,9 @@ static int lxcProcRead(const char *path G_GNUC_UNUSED,
if (STREQ(path, fuse_meminfo_path)) {
if ((res = lxcProcReadMeminfo(hostpath, def, buf, size, offset)) < 0)
res = lxcProcHostRead(hostpath, buf, size, offset);
+ } else if (STREQ(path, fuse_cpuinfo_path)) {
+ if ((res = lxcProcReadCpuinfo(hostpath, def, buf, size, offset)) < 0)
+ res = lxcProcHostRead(hostpath, buf, size, offset);
}
return res;
--
2.20.1
