On 11/18/2015 07:01 PM, Jim Fehlig wrote:
> On 11/13/2015 06:14 AM, 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 devno libxlDiskPathToID is introduced.
>> 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>
>> ---
>> Changes since v1:
>> - Fix identation issues
>> - Set ret to LIBXL_VBD_SECTOR_SIZE
>> - Reuse VIR_STRDUP error instead of doing virReportError
>> when we fail to set stats->backend
>> - Change virAsprintf(...) error checking
>> - Change error to VIR_ERR_OPERATION_FAILED when xenstore path
>> does not exist and when failing to read stat.
>> - Resolve issues with 'make syntax-check' with cppi installed.
>> - Remove libxlDiskPathMatches in favor of using virutil
>> virDiskNameParse to fetch disk and partition index.
>> - Rename libxlDiskPathParse to libxlDiskPathToID and rework
>> function to just convert disk and partition index to devno.
>> - Bump version to 1.2.22
>> ---
>> configure.ac | 2 +-
>> src/libxl/libxl_driver.c | 375 +++++++++++++++++++++++++++++++++++++++++++++++
>> 2 files changed, 376 insertions(+), 1 deletion(-)
>>
>> diff --git a/configure.ac b/configure.ac
>> index f481c50..10c56e5 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 9a5a74c..ba1d67b 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,
>> @@ -4644,6 +4665,358 @@ libxlDomainIsUpdated(virDomainPtr dom)
>> }
>>
>> static int
>> +libxlDiskPathToID(const char *virtpath)
>> +{
>> + static char const* drive_prefix[] = {"xvd", "hd", "sd"};
>> + int disk, partition, chrused;
>> + int fmt, id;
>> + char *r;
>> + size_t i;
>> +
>> + fmt = id = -1;
>> +
>> + /* Find any disk prefixes we know about */
>> + for (i = 0; i < ARRAY_CARDINALITY(drive_prefix); i++) {
>> + if (STRPREFIX(virtpath, drive_prefix[i]) &&
>> + !virDiskNameParse(virtpath, &disk, &partition)) {
>> + fmt = i;
>> + break;
>> + }
>> + }
>> +
>> + /* Handle it same way as xvd */
>> + if (fmt < 0 &&
>> + (sscanf(virtpath, "d%ip%i%n", &disk, &partition, &chrused) >= 2
>> + && chrused == strlen(virtpath)))
>> + fmt = 0;
>> +
>> + /* Test indexes ranges and calculate the device id */
>> + switch (fmt) {
>> + case 0: /* xvd */
>> + if (disk <= 15 && partition <= 15)
>> + id = (202 << 8) | (disk << 4) | partition;
>> + else if ((disk <= ((1<<20)-1)) || partition <= 255)
>> + id = (1 << 28) | (disk << 8) | partition;
>> + break;
>> + case 1: /* hd */
>> + if (disk <= 3 && partition <= 63)
>> + id = ((disk < 2 ? 3 : 22) << 8) | ((disk & 1) << 6) | partition;
>> + break;
>> + case 2: /* sd */
>> + if (disk <= 15 && (partition <= 15))
>> + id = (8 << 8) | (disk << 4) | partition;
>> + break;
>> + default:
>> + errno = virStrToLong_i(virtpath, &r, 0, &id);
>> + if (errno || *r || id > INT_MAX)
>> + id = -1;
>> + break;
>> + }
>> + return id;
>> +}
>> +
>> +#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"));
>
> Probably no need to report an error here since LIBXL_VBD_SECTOR_SIZE is returned
> and used by the caller. Maybe a VIR_WARN is more appropriate.
>
OK.
>> + return ret;
>> + }
>> +
>> + if (virAsprintf(&path, "/local/domain/%d/device/vbd/%d/backend",
>> + domid, devno) < 0)
>> + goto close;
>
> Perhaps a bit cleaner to initialize path and val to NULL then have a single
> 'cleanup' label where they are freed. Then you would only need to VIR_FREE path
> and val before re-purposing them.
>
Good point. I will rework it that way.
>> +
>> + 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 = LIBXL_VBD_SECTOR_SIZE;
>> +
>> + 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 = libxlDiskPathToID(dev);
>> + int size = libxlDiskSectorSize(vm->def->id, devno);
>> +#ifdef __linux__
>> + char *path, *name, *val;
>> + unsigned long long stat;
>> +
>> + path = name = val = NULL;
>> + if (devno < 0) {
>> + virReportError(VIR_ERR_OPERATION_INVALID,
>> + "%s", _("cannot find device number"));
>> + return ret;
>> + }
>> + if (VIR_STRDUP(stats->backend, "vbd") < 0)
>> + return ret;
>> +
>> + if (virAsprintf(&path, "/sys/bus/xen-backend/devices/vbd-%d-%d/statistics",
>> + vm->def->id, devno) < 0)
>> + return ret;
>> +
>> + if (!virFileExists(path)) {
>> + virReportError(VIR_ERR_OPERATION_FAILED,
>> + "%s", _("cannot open bus path"));
>> + goto cleanup;
>> + }
>> +
>> +# define LIBXL_SET_VBDSTAT(FIELD, VAR, MUL) \
>> + if ((virAsprintf(&name, "%s/"FIELD, path) < 0) || \
>> + (virFileReadAll(name, 256, &val) < 0) || \
>> + (sscanf(val, "%llu", &stat) != 1)) { \
>> + virReportError(VIR_ERR_OPERATION_FAILED, \
>> + _("cannot read %s"), name); \
>> + 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);
>> +
>> +# undef LIBXL_SET_VBDSTAT
>> +
>> +#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;
>
> Indentation looks off.
>
OK, and also remove this unnecessary return there.
>> + }
>> + 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;
>> + }
>
> Currently, libxlDomainObjEndJob returns false when the virDomainObj refcnt has
> reached 0, in which case it will be disposed and doesn't need unlocked. Notice
> the pattern in all the other calls to libxlDomainObjEndJob. (I say 'currently'
> because I'm working on a patch to change the ref counting and job handling
> similar to commit 540c339a for the QEMU driver.)
>
You mean the followup of this one right?
(https://www.redhat.com/archives/libvir-list/2015-June/msg00711.html). It
appears I do the same mistake on InterfaceStats and ConnectGetAllDomainStats, so
I will fix that too.
>> +
>> + 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;
>> + }
>
> Same comment here.
>
OK.
> Regards,
> Jim
>
>
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