Joao Martins wrote:
> Introduce initial support for domainBlockStats API call that
> allow us to query block device statistics. openstack nova
> uses this API call to query block statistics, alongside
> virDomainMemoryStats and virDomainInterfaceStats. Note that
> this patch only introduces it for VBD for starters. QDisk
> will come in a separate patch series.
>
> A new statistics data structure is introduced to fit common
> statistics among others specific to the underlying block
> backends. For the VBD statistics on linux these are exported
> via sysfs on the path:
>
> "/sys/bus/xen-backend/devices/vbd-<domid>-<devid>/statistics"
>
> To calculate the block devid two libxl functions were ported
> (libxlDiskPathMatches and libxlDiskPathParse) to libvirt to
> make sure the devid is calculate in the same way as libxl.
> Each backend implements its own function to extract statistics
> and let there be handled the different platforms. An alternative
> would be to reuse libvirt xen driver function.
>
> VBD stats are exposed in reqs and number of sectors from
> blkback, and it's up to us to convert it to sector sizes.
> The sector size is gathered through xenstore in the device
> backend entry "physical-sector-size". This adds up an extra
> dependency namely of xenstore for doing the xs_read.
>
> BlockStatsFlags variant is also implemented which has the
> added benefit of getting the number of flush requests.
>
> Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
> ---
> configure.ac | 2 +-
> src/libxl/libxl_driver.c | 420 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 421 insertions(+), 1 deletion(-)
>
> diff --git a/configure.ac b/configure.ac
> index ef7fbdb..56fb266 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -896,7 +896,7 @@ if test "$with_libxl" != "no" ; then
> LIBS="$LIBS $LIBXL_LIBS"
> AC_CHECK_LIB([xenlight], [libxl_ctx_alloc], [
> with_libxl=yes
> - LIBXL_LIBS="$LIBXL_LIBS -lxenlight -lxenctrl"
> + LIBXL_LIBS="$LIBXL_LIBS -lxenlight -lxenctrl -lxenstore"
> ],[
> if test "$with_libxl" = "yes"; then
> fail=1
> diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
> index dc83083..fd952a3 100644
> --- a/src/libxl/libxl_driver.c
> +++ b/src/libxl/libxl_driver.c
> @@ -59,6 +59,7 @@
> #include "network/bridge_driver.h"
> #include "locking/domain_lock.h"
> #include "virstats.h"
> +#include <xenstore.h>
>
> #define VIR_FROM_THIS VIR_FROM_LIBXL
>
> @@ -75,6 +76,7 @@ VIR_LOG_INIT("libxl.libxl_driver");
> #define LIBXL_CONFIG_FORMAT_SEXPR "xen-sxpr"
>
> #define LIBXL_NB_TOTAL_CPU_STAT_PARAM 1
> +#define LIBXL_NB_TOTAL_BLK_STAT_PARAM 6
>
> #define HYPERVISOR_CAPABILITIES "/proc/xen/capabilities"
> #define HYPERVISOR_XENSTORED "/dev/xen/xenstored"
> @@ -103,6 +105,25 @@ struct _libxlOSEventHookInfo {
> int id;
> };
>
> +/* Object used to store disk statistics across multiple xen backends */
> +typedef struct _libxlBlockStats libxlBlockStats;
> +typedef libxlBlockStats *libxlBlockStatsPtr;
> +struct _libxlBlockStats {
> + long long rd_req;
> + long long rd_bytes;
> + long long wr_req;
> + long long wr_bytes;
> + long long f_req;
> +
> + char *backend;
> + union {
> + struct {
> + long long ds_req;
> + long long oo_req;
> + } vbd;
> + } u;
> +};
> +
> /* Function declarations */
> static int
> libxlDomainManagedSaveLoad(virDomainObjPtr vm,
> @@ -4641,6 +4662,403 @@ libxlDomainIsUpdated(virDomainPtr dom)
> }
>
> static int
> +libxlDiskPathMatches(const char *virtpath, const char *devtype,
> + int *index_r, int max_index,
> + int *partition_r, int max_partition)
> +{
> + const char *p;
> + char *ep;
> + int tl, c;
> + long pl;
> +
> + tl = strlen(devtype);
> + if (memcmp(virtpath, devtype, tl))
> + return 0;
> +
> + /* We decode the drive letter as if it were in base 52
> + * with digits a-zA-Z, more or less */
> + *index_r = -1;
> + p = virtpath + tl;
> + for (;;) {
> + c = *p++;
> + if (c >= 'a' && c <= 'z') {
> + c -= 'a';
> + } else {
> + --p;
> + break;
> + }
> + (*index_r)++;
> + (*index_r) *= 26;
> + (*index_r) += c;
> +
> + if (*index_r > max_index)
> + return 0;
> + }
> +
> + if (!*p) {
> + *partition_r = 0;
> + return 1;
> + }
> +
> + if (*p == '0')
> + return 0; /* leading zeroes not permitted in partition number */
> +
> + if (virStrToLong_l(p, &ep, 10, &pl) < 0)
> + return 0;
> +
> + if (pl > max_partition || *ep)
> + return 0;
> +
> + *partition_r = pl;
> + return 1;
> +}
> +
> +static int
> +libxlDiskPathParse(const char *virtpath, int *pdisk, int *ppartition)
> +{
> + int disk, partition;
> + char *ep;
> + unsigned long ul;
> + int chrused;
> +
> + chrused = -1;
> + if ((sscanf(virtpath, "d%ip%i%n", &disk, &partition, &chrused) >= 2
> + && chrused == strlen(virtpath) && disk < (1<<20) && partition < 256)
> + ||
> + libxlDiskPathMatches(virtpath, "xvd",
> + &disk, (1<<20)-1,
> + &partition, 255)) {
> + if (pdisk) *pdisk = disk;
> + if (ppartition) *ppartition = partition;
> + if (disk <= 15 && partition <= 15)
> + return (202 << 8) | (disk << 4) | partition;
> + else
> + return (1 << 28) | (disk << 8) | partition;
> + }
> +
> + errno = virStrToLong_ul(virtpath, &ep, 0, &ul);
> + if (!errno && !*ep && ul <= INT_MAX) {
> + /* FIXME: should parse ul to determine these. */
> + if (pdisk || ppartition)
> + return -1;
> + return ul;
> + }
> +
> + if (libxlDiskPathMatches(virtpath, "hd",
> + &disk, 3,
> + &partition, 63)) {
> + if (pdisk) *pdisk = disk;
> + if (ppartition) *ppartition = partition;
> + return ((disk<2 ? 3 : 22) << 8) | ((disk & 1) << 6) | partition;
> + }
> + if (libxlDiskPathMatches(virtpath, "sd",
> + &disk, 15,
> + &partition, 15)) {
> + if (pdisk) *pdisk = disk;
> + if (ppartition) *ppartition = partition;
> + return (8 << 8) | (disk << 4) | partition;
> + }
> + return -1;
> +}
> +
> +#define LIBXL_VBD_SECTOR_SIZE 512
> +
> +static int
> +libxlDiskSectorSize(int domid, int devno)
> +{
> + char *path, *val;
> + struct xs_handle *handle;
> + int ret = LIBXL_VBD_SECTOR_SIZE;
> + unsigned int len;
> +
> + handle = xs_daemon_open_readonly();
> + if (!handle) {
> + virReportError(VIR_ERR_INTERNAL_ERROR,
> + "%s", _("cannot read sector size"));
> + return ret;
> + }
> +
> + if (virAsprintf(&path, "/local/domain/%d/device/vbd/%d/backend",
> + domid, devno) < 0)
>
Indentation looks off.
> + goto close;
> +
> + if ((val = xs_read(handle, XBT_NULL, path, &len)) == NULL)
> + goto cleanup;
> +
> + VIR_FREE(path);
> + if (virAsprintf(&path, "%s/physical-sector-size", val) < 0) {
> + VIR_FREE(val);
> + goto close;
> + }
> +
> + VIR_FREE(val);
> + if ((val = xs_read(handle, XBT_NULL, path, &len)) == NULL)
> + goto cleanup;
> +
> + if (sscanf(val, "%d", &ret) != 1)
> + ret = -1;
>
Should ret be set back to LIBXL_VBD_SECTOR_SIZE? '-1' wouldn't be a good
value for the calling function.
> +
> + VIR_FREE(val);
> +
> + cleanup:
> + VIR_FREE(path);
> + close:
> + xs_daemon_close(handle);
> + return ret;
> +}
> +
> +static int
> +libxlDomainBlockStatsVBD(virDomainObjPtr vm,
> + const char *dev,
> + libxlBlockStatsPtr stats)
> +{
> + int ret = -1;
> + int devno = libxlDiskPathParse(dev, NULL, NULL);
> + int size = libxlDiskSectorSize(vm->def->id, devno);
> +#ifdef __linux__
> + char *path, *name, *val;
> + unsigned long long stat;
> +
> + if (VIR_STRDUP(stats->backend, "vbd") < 0) {
> + virReportError(VIR_ERR_OPERATION_INVALID,
> + "%s", _("cannot set backend"));
>
VIR_STRDUP() already reports OOM error, which is about the only one it
can encounter.
> + return -1;
> + }
> +
> + ret = virAsprintf(&path, "/sys/bus/xen-backend/devices/vbd-%d-%d/statistics",
> + vm->def->id, devno);
>
The usual pattern is 'if (virAsprintf(...) < 0)'.
> +
> + if (!virFileExists(path)) {
> + virReportError(VIR_ERR_OPERATION_INVALID,
> + "%s", _("cannot open bus path"));
>
I think the error should be VIR_ERR_OPERATION_FAILED.
> + goto cleanup;
> + }
> +
> +#define LIBXL_SET_VBDSTAT(FIELD, VAR, MUL) \
>
Indentation is off here. Fails 'make syntax-check' with cppi installed.
> + if ((virAsprintf(&name, "%s/"FIELD, path) < 0) || \
> + (virFileReadAll(name, 256, &val) < 0) || \
> + (sscanf(val, "%llu", &stat) != 1)) { \
> + virReportError(VIR_ERR_OPERATION_INVALID, \
> + _("cannot read %s"), name); \
>
VIR_ERR_OPERATION_FAILED?
> + goto cleanup; \
> + } \
> + VAR += (stat * MUL); \
> + VIR_FREE(name); \
> + VIR_FREE(val);
> +
> + LIBXL_SET_VBDSTAT("f_req", stats->f_req, 1)
> + LIBXL_SET_VBDSTAT("wr_req", stats->wr_req, 1)
> + LIBXL_SET_VBDSTAT("rd_req", stats->rd_req, 1)
> + LIBXL_SET_VBDSTAT("wr_sect", stats->wr_bytes, size)
> + LIBXL_SET_VBDSTAT("rd_sect", stats->rd_bytes, size)
> +
> + LIBXL_SET_VBDSTAT("ds_req", stats->u.vbd.ds_req, size)
> + LIBXL_SET_VBDSTAT("oo_req", stats->u.vbd.oo_req, 1)
> + ret = 0;
> +
> + cleanup:
> + VIR_FREE(name);
> + VIR_FREE(path);
> + VIR_FREE(val);
>
This will only cleanup 'name' and 'val' from the last invocation of the
LIBXL_SET_VBDSTAT macro. 'name' and 'val' from the prior invocations
will be leaked.
> +
> +#undef LIBXL_SET_VBDSTAT
>
Another case of failing 'make syntax-check' with cppi installed.
Regards,
Jim
> +
> +#else
> + virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> + "%s", _("platform unsupported"));
> +#endif
> + return ret;
> +}
> +
> +static int
> +libxlDomainBlockStatsGatherSingle(virDomainObjPtr vm,
> + const char *path,
> + libxlBlockStatsPtr stats)
> +{
> + virDomainDiskDefPtr disk;
> + const char *disk_drv;
> + int ret = -1, disk_fmt;
> +
> + if (!(disk = virDomainDiskByName(vm->def, path, false))) {
> + virReportError(VIR_ERR_OPERATION_INVALID,
> + _("invalid path: %s"), path);
> + return ret;
> + }
> +
> + disk_fmt = virDomainDiskGetFormat(disk);
> + if (!(disk_drv = virDomainDiskGetDriver(disk)))
> + disk_drv = "qemu";
> +
> + if (STREQ(disk_drv, "phy")) {
> + if (disk_fmt != VIR_STORAGE_FILE_RAW &&
> + disk_fmt != VIR_STORAGE_FILE_NONE) {
> + virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> + _("unsupported format %s"),
> + virStorageFileFormatTypeToString(disk_fmt));
> + return ret;
> + }
> +
> + ret = libxlDomainBlockStatsVBD(vm, path, stats);
> + } else {
> + virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> + _("unsupported disk driver %s"),
> + disk_drv);
> + return ret;
> + }
> + return ret;
> +}
> +
> +static int
> +libxlDomainBlockStatsGather(virDomainObjPtr vm,
> + const char *path,
> + libxlBlockStatsPtr stats)
> +{
> + int ret = -1;
> + if (*path) {
> + if (libxlDomainBlockStatsGatherSingle(vm, path, stats) < 0)
> + return ret;
> + } else {
> + size_t i;
> + for (i = 0; i < vm->def->ndisks; ++i) {
> + if (libxlDomainBlockStatsGatherSingle(vm, vm->def->disks[i]->dst,
> + stats) < 0)
> + return ret;
> + }
> + }
> + return 0;
> +}
> +
> +static int
> +libxlDomainBlockStats(virDomainPtr dom,
> + const char *path,
> + virDomainBlockStatsPtr stats)
> +{
> + libxlDriverPrivatePtr driver = dom->conn->privateData;
> + virDomainObjPtr vm;
> + libxlBlockStats blkstats;
> + int ret = -1;
> +
> + if (!(vm = libxlDomObjFromDomain(dom)))
> + goto cleanup;
> +
> + if (virDomainBlockStatsEnsureACL(dom->conn, vm->def) < 0)
> + goto cleanup;
> +
> + if (libxlDomainObjBeginJob(driver, vm, LIBXL_JOB_QUERY) < 0)
> + goto cleanup;
> +
> + if (!virDomainObjIsActive(vm)) {
> + virReportError(VIR_ERR_OPERATION_INVALID,
> + "%s", _("domain is not running"));
> + goto endjob;
> + }
> +
> + memset(&blkstats, 0, sizeof(libxlBlockStats));
> + if ((ret = libxlDomainBlockStatsGather(vm, path, &blkstats)) < 0)
> + goto endjob;
> +
> + stats->rd_req = blkstats.rd_req;
> + stats->rd_bytes = blkstats.rd_bytes;
> + stats->wr_req = blkstats.wr_req;
> + stats->wr_bytes = blkstats.wr_bytes;
> + if (STREQ_NULLABLE(blkstats.backend, "vbd"))
> + stats->errs = blkstats.u.vbd.oo_req;
> + else
> + stats->errs = -1;
> +
> + endjob:
> + if (!libxlDomainObjEndJob(driver, vm)) {
> + virObjectUnlock(vm);
> + vm = NULL;
> + }
> +
> + cleanup:
> + if (vm)
> + virObjectUnlock(vm);
> + return ret;
> +}
> +
> +static int
> +libxlDomainBlockStatsFlags(virDomainPtr dom,
> + const char *path,
> + virTypedParameterPtr params,
> + int *nparams,
> + unsigned int flags)
> +{
> + libxlDriverPrivatePtr driver = dom->conn->privateData;
> + virDomainObjPtr vm;
> + libxlBlockStats blkstats;
> + int nstats;
> + int ret = -1;
> +
> + virCheckFlags(VIR_TYPED_PARAM_STRING_OKAY, -1);
> +
> + flags &= ~VIR_TYPED_PARAM_STRING_OKAY;
> +
> + if (!(vm = libxlDomObjFromDomain(dom)))
> + goto cleanup;
> +
> + if (virDomainBlockStatsFlagsEnsureACL(dom->conn, vm->def) < 0)
> + goto cleanup;
> +
> + if (libxlDomainObjBeginJob(driver, vm, LIBXL_JOB_QUERY) < 0)
> + goto cleanup;
> +
> + if (!virDomainObjIsActive(vm)) {
> + virReportError(VIR_ERR_OPERATION_INVALID,
> + "%s", _("domain is not running"));
> + goto endjob;
> + }
> +
> + /* return count of supported stats */
> + if (*nparams == 0) {
> + *nparams = LIBXL_NB_TOTAL_BLK_STAT_PARAM;
> + ret = 0;
> + goto endjob;
> + }
> +
> + memset(&blkstats, 0, sizeof(libxlBlockStats));
> + if ((ret = libxlDomainBlockStatsGather(vm, path, &blkstats)) < 0)
> + goto endjob;
> +
> + nstats = 0;
> +
> +#define LIBXL_BLKSTAT_ASSIGN_PARAM(VAR, NAME) \
> + if (nstats < *nparams && (blkstats.VAR) != -1) { \
> + if (virTypedParameterAssign(params + nstats, NAME, \
> + VIR_TYPED_PARAM_LLONG, (blkstats.VAR)) < 0) \
> + goto endjob; \
> + nstats++; \
> + }
> +
> + LIBXL_BLKSTAT_ASSIGN_PARAM(wr_bytes, VIR_DOMAIN_BLOCK_STATS_WRITE_BYTES);
> + LIBXL_BLKSTAT_ASSIGN_PARAM(wr_req, VIR_DOMAIN_BLOCK_STATS_WRITE_REQ);
> +
> + LIBXL_BLKSTAT_ASSIGN_PARAM(rd_bytes, VIR_DOMAIN_BLOCK_STATS_READ_BYTES);
> + LIBXL_BLKSTAT_ASSIGN_PARAM(rd_req, VIR_DOMAIN_BLOCK_STATS_READ_REQ);
> +
> + LIBXL_BLKSTAT_ASSIGN_PARAM(f_req, VIR_DOMAIN_BLOCK_STATS_FLUSH_REQ);
> +
> + if (STREQ_NULLABLE(blkstats.backend, "vbd"))
> + LIBXL_BLKSTAT_ASSIGN_PARAM(u.vbd.oo_req, VIR_DOMAIN_BLOCK_STATS_ERRS);
> +
> + *nparams = nstats;
> +
> +#undef LIBXL_BLKSTAT_ASSIGN_PARAM
> +
> + endjob:
> + if (!libxlDomainObjEndJob(driver, vm)) {
> + virObjectUnlock(vm);
> + vm = NULL;
> + }
> +
> + cleanup:
> + if (vm)
> + virObjectUnlock(vm);
> + return ret;
> +}
> +
> +static int
> libxlDomainInterfaceStats(virDomainPtr dom,
> const char *path,
> virDomainInterfaceStatsPtr stats)
> @@ -5459,6 +5877,8 @@ static virHypervisorDriver libxlHypervisorDriver = {
> #endif
> .nodeGetFreeMemory = libxlNodeGetFreeMemory, /* 0.9.0 */
> .nodeGetCellsFreeMemory = libxlNodeGetCellsFreeMemory, /* 1.1.1 */
> + .domainBlockStats = libxlDomainBlockStats, /* 1.2.20 */
> + .domainBlockStatsFlags = libxlDomainBlockStatsFlags, /* 1.2.20 */
> .domainInterfaceStats = libxlDomainInterfaceStats, /* 1.2.20 */
> .domainMemoryStats = libxlDomainMemoryStats, /* 1.2.20 */
> .domainGetCPUStats = libxlDomainGetCPUStats, /* 1.2.20 */
>
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list