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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v2] xentop: add support for qdisks
Now that Xen uses qdisks by default and qemu does not write out
statistics to sysfs this patch queries the QMP for disk statistics.
This patch depends on libyajl for parsing statistics returned from
QMP. The runtime requires libyajl 2.0.3 or newer for required bug
fixes in yajl_tree_parse().
No interfaces have been changed. It works within the existing
framework of libxenstat.
Signed-off-by: Charles Arnold <carnold@xxxxxxxx>
diff --git a/tools/xenstat/libxenstat/Makefile
b/tools/xenstat/libxenstat/Makefile
index 07d39b1..6a69f7e 100644
--- a/tools/xenstat/libxenstat/Makefile
+++ b/tools/xenstat/libxenstat/Makefile
@@ -24,7 +24,7 @@ MINOR=0
LIB=src/libxenstat.a
SHLIB=src/libxenstat.so.$(MAJOR).$(MINOR)
SHLIB_LINKS=src/libxenstat.so.$(MAJOR) src/libxenstat.so
-OBJECTS-y=src/xenstat.o
+OBJECTS-y=src/xenstat.o src/xenstat_qmp.o
OBJECTS-$(CONFIG_Linux) += src/xenstat_linux.o
OBJECTS-$(CONFIG_SunOS) += src/xenstat_solaris.o
OBJECTS-$(CONFIG_NetBSD) += src/xenstat_netbsd.o
diff --git a/tools/xenstat/libxenstat/src/xenstat.c
b/tools/xenstat/libxenstat/src/xenstat.c
index 8072a90..f3847be 100644
--- a/tools/xenstat/libxenstat/src/xenstat.c
+++ b/tools/xenstat/libxenstat/src/xenstat.c
@@ -657,6 +657,24 @@ static void xenstat_uninit_xen_version(xenstat_handle *
handle)
* VBD functions
*/
+/* Save VBD information */
+xenstat_vbd *xenstat_save_vbd(xenstat_domain *domain, xenstat_vbd *vbd)
+{
+ if (domain->vbds == NULL) {
+ domain->num_vbds = 1;
+ domain->vbds = malloc(sizeof(xenstat_vbd));
+ } else {
+ domain->num_vbds++;
+ domain->vbds = realloc(domain->vbds,
+ domain->num_vbds *
+ sizeof(xenstat_vbd));
+ }
+ if (domain->vbds != NULL)
+ domain->vbds[domain->num_vbds - 1] = *vbd;
+
+ return domain->vbds;
+}
+
/* Free VBD information */
static void xenstat_free_vbds(xenstat_node * node)
{
diff --git a/tools/xenstat/libxenstat/src/xenstat_linux.c
b/tools/xenstat/libxenstat/src/xenstat_linux.c
index 7fdf70a..2cc9c7f 100644
--- a/tools/xenstat/libxenstat/src/xenstat_linux.c
+++ b/tools/xenstat/libxenstat/src/xenstat_linux.c
@@ -417,6 +417,9 @@ int xenstat_collect_vbds(xenstat_node * node)
}
}
+ /* Get qdisk statistics */
+ read_attributes_qdisk(node);
+
rewinddir(priv->sysfsvbd);
for(dp = readdir(priv->sysfsvbd); dp != NULL ;
@@ -477,18 +480,10 @@ int xenstat_collect_vbds(xenstat_node * node)
continue;
}
- if (domain->vbds == NULL) {
- domain->num_vbds = 1;
- domain->vbds = malloc(sizeof(xenstat_vbd));
- } else {
- domain->num_vbds++;
- domain->vbds = realloc(domain->vbds,
- domain->num_vbds *
- sizeof(xenstat_vbd));
- }
- if (domain->vbds == NULL)
+ if ((xenstat_save_vbd(domain, &vbd)) == NULL) {
+ perror("Allocation error");
return 0;
- domain->vbds[domain->num_vbds - 1] = vbd;
+ }
}
return 1;
diff --git a/tools/xenstat/libxenstat/src/xenstat_priv.h
b/tools/xenstat/libxenstat/src/xenstat_priv.h
index 8490e23..74e0774 100644
--- a/tools/xenstat/libxenstat/src/xenstat_priv.h
+++ b/tools/xenstat/libxenstat/src/xenstat_priv.h
@@ -109,5 +109,7 @@ extern int xenstat_collect_networks(xenstat_node * node);
extern void xenstat_uninit_networks(xenstat_handle * handle);
extern int xenstat_collect_vbds(xenstat_node * node);
extern void xenstat_uninit_vbds(xenstat_handle * handle);
+extern void read_attributes_qdisk(xenstat_node * node);
+extern xenstat_vbd *xenstat_save_vbd(xenstat_domain * domain, xenstat_vbd *
vbd);
#endif /* XENSTAT_PRIV_H */
diff --git a/tools/xenstat/xentop/Makefile b/tools/xenstat/xentop/Makefile
index e2665aa..5376fdc 100644
--- a/tools/xenstat/xentop/Makefile
+++ b/tools/xenstat/xentop/Makefile
@@ -19,7 +19,7 @@ all install xentop:
else
CFLAGS += -DGCC_PRINTF -Werror $(CFLAGS_libxenstat)
-LDLIBS += $(LDLIBS_libxenstat) $(CURSES_LIBS) $(SOCKET_LIBS) -lm
+LDLIBS += $(LDLIBS_libxenstat) $(CURSES_LIBS) $(SOCKET_LIBS) -lm -lyajl
CFLAGS += -DHOST_$(XEN_OS)
# Include configure output (config.h) to headers search path
diff --git a/tools/xenstat/libxenstat/src/xenstat_qmp.c
b/tools/xenstat/libxenstat/src/xenstat_qmp.c
new file mode 100644
index 0000000..aac4637
--- /dev/null
+++ b/tools/xenstat/libxenstat/src/xenstat_qmp.c
@@ -0,0 +1,387 @@
+/* libxenstat: statistics-collection library for Xen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/poll.h>
+#include <sys/un.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "yajl/yajl_tree.h"
+
+#include <xenctrl.h>
+
+#include "xenstat_priv.h"
+
+static unsigned char *qmp_query(int, char *);
+
+enum query_blockstats {
+ QMP_STATS_RETURN = 0,
+ QMP_STATS_DEVICE = 1,
+ QMP_STATS = 2,
+ QMP_RD_BYTES = 3,
+ QMP_WR_BYTES = 4,
+ QMP_RD_OPERATIONS = 5,
+ QMP_WR_OPERATIONS = 6,
+};
+
+enum query_block {
+ QMP_BLOCK_RETURN = 0,
+ QMP_BLOCK_DEVICE = 1,
+ QMP_INSERTED = 2,
+ QMP_FILE = 3,
+};
+
+
+/* Given the qmp device name, get the image filename associated with it */
+static char *qmp_get_block_image(xenstat_node *node, char *qmp_devname, int
qfd)
+{
+ char errbuf[1024], *tmp, *file = NULL;
+ char *query_block_cmd = "{ \"execute\": \"query-block\" }";
+ static const char *const qblock[] = {
+ [ QMP_BLOCK_RETURN ] = "return",
+ [ QMP_BLOCK_DEVICE ] = "device",
+ [ QMP_INSERTED ] = "inserted",
+ [ QMP_FILE ] = "file",
+ };
+ const char *ptr[] = {0, 0};
+ unsigned char *qmp_stats;
+ yajl_val info, ret_obj, dev_obj, n;
+ int i;
+
+ if ((qmp_stats = qmp_query(qfd, query_block_cmd)) == NULL)
+ return NULL;
+
+ /* Use libyajl version 2.1.x or newer for the tree parser feature with
bug fixes */
+ if ((info = yajl_tree_parse((char *)qmp_stats, errbuf, sizeof(errbuf)))
== NULL) {
+ free(qmp_stats);
+ return NULL;
+ }
+
+ ptr[0] = qblock[QMP_BLOCK_RETURN]; /* "return" */
+ if ((ret_obj = yajl_tree_get(info, ptr, yajl_t_array)) == NULL)
+ goto done;
+
+ for (i=0; i<YAJL_GET_ARRAY(ret_obj)->len; i++) {
+ n = YAJL_GET_ARRAY(ret_obj)->values[i];
+
+ ptr[0] = qblock[QMP_BLOCK_DEVICE]; /* "device" */
+ if ((dev_obj = yajl_tree_get(n, ptr, yajl_t_any)) != NULL) {
+ tmp = YAJL_GET_STRING(dev_obj);
+ if (strcmp(qmp_devname, tmp))
+ continue;
+ }
+ else
+ continue;
+
+ ptr[0] = qblock[QMP_INSERTED]; /* "inserted" */
+ n = yajl_tree_get(n, ptr, yajl_t_any);
+ if (n) {
+ ptr[0] = qblock[QMP_FILE]; /* "file" */
+ n = yajl_tree_get(n, ptr, yajl_t_any);
+ if (n && YAJL_IS_STRING(n)) {
+ tmp = YAJL_GET_STRING(n);
+ file = malloc(strlen(tmp)+1);
+ if (file != NULL)
+ strcpy(file, tmp);
+ goto done;
+ }
+ }
+ }
+done:
+ yajl_tree_free(info);
+ return file;
+}
+
+
+/* Given a QMP device name, find the associated xenstore qdisk device id */
+static void get_xs_devid_from_qmp_devname(xenstat_node * node, unsigned int
domid, char *qmp_devname,
+ unsigned int *dev, unsigned int *sector_size, int qfd)
+{
+ char **dev_ids, *tmp, *ptr, *image, path[80];
+ unsigned int num_dev_ids;
+ int i, devid;
+
+ /* Get all the qdisk dev IDs associated with the this VM */
+ snprintf(path, sizeof(path),"/local/domain/0/backend/qdisk/%i", domid);
+ dev_ids = xs_directory(node->handle->xshandle, XBT_NULL, path,
&num_dev_ids);
+ if (dev_ids == NULL) {
+ return;
+ }
+
+ /* Get the filename of the image associated with this QMP device */
+ image = qmp_get_block_image(node, qmp_devname, qfd);
+ if (image == NULL) {
+ free(dev_ids);
+ return;
+ }
+
+ /* Look for a matching image in xenstore */
+ for (i=0; i<num_dev_ids; i++) {
+ devid = atoi(dev_ids[i]);
+ /* Get the xenstore name of the image */
+ snprintf(path,
sizeof(path),"/local/domain/0/backend/qdisk/%i/%i/params", domid, devid);
+ if ((ptr = xs_read(node->handle->xshandle, XBT_NULL, path,
NULL)) == NULL)
+ continue;
+
+ /* Get to actual path in string */
+ if ((tmp = strchr(ptr, '/')) == NULL)
+ tmp = ptr;
+ if (!strcmp(tmp,image)) {
+ *dev = devid;
+ free(ptr);
+
+ /* Get the xenstore sector size of the image while
we're here */
+ snprintf(path,
sizeof(path),"/local/domain/0/backend/qdisk/%i/%i/sector-size", domid, devid);
+ if ((ptr = xs_read(node->handle->xshandle, XBT_NULL,
path, NULL)) != NULL) {
+ *sector_size = atoi((char *)ptr);
+ free(ptr);
+ }
+ break;
+ }
+ free(ptr);
+ }
+
+ free(image);
+ free(dev_ids);
+}
+
+/* Parse the stats buffer which contains I/O data for all the disks belonging
to domid */
+static void qmp_parse_stats(xenstat_node *node, unsigned int domid, unsigned
char *stats_buf, int qfd)
+{
+ char *qmp_devname, errbuf[1024];
+ static const char *const qstats[] = {
+ [ QMP_STATS_RETURN ] = "return",
+ [ QMP_STATS_DEVICE ] = "device",
+ [ QMP_STATS ] = "stats",
+ [ QMP_RD_BYTES ] = "rd_bytes",
+ [ QMP_WR_BYTES ] = "wr_bytes",
+ [ QMP_RD_OPERATIONS ] = "rd_operations",
+ [ QMP_WR_OPERATIONS ] = "wr_operations",
+ };
+ const char *ptr[] = {0, 0};
+ yajl_val info, ret_obj, stats_obj, n;
+ xenstat_vbd vbd;
+ xenstat_domain *domain;
+ unsigned int sector_size = 512;
+ int i, j;
+
+ /* Use libyajl version 2.0.3 or newer for the tree parser feature */
+ if ((info = yajl_tree_parse((char *)stats_buf, errbuf, sizeof(errbuf)))
== NULL)
+ return;
+
+ ptr[0] = qstats[QMP_STATS_RETURN]; /* "return" */
+ if ((ret_obj = yajl_tree_get(info, ptr, yajl_t_array)) == NULL)
+ goto done;
+
+ /* Array of devices */
+ for (i=0; i<YAJL_GET_ARRAY(ret_obj)->len; i++) {
+ memset(&vbd, 0, sizeof(xenstat_vbd));
+ qmp_devname = NULL;
+ stats_obj = YAJL_GET_ARRAY(ret_obj)->values[i];
+
+ ptr[0] = qstats[QMP_STATS_DEVICE]; /* "device" */
+ if ((n = yajl_tree_get(stats_obj, ptr, yajl_t_any)) != NULL)
+ qmp_devname = YAJL_GET_STRING(n);
+
+ ptr[0] = qstats[QMP_STATS]; /* "stats" */
+ stats_obj = yajl_tree_get(stats_obj, ptr, yajl_t_object);
+ if (stats_obj && YAJL_IS_OBJECT(stats_obj)) {
+ for (j=3; j<7; j++) {
+ ptr[0] = qstats[j];
+ n = yajl_tree_get(stats_obj, ptr,
yajl_t_number);
+ if (n && YAJL_IS_NUMBER(n)) {
+ switch(j) {
+ case QMP_RD_BYTES: /* "rd_bytes" */
+ vbd.rd_sects =
YAJL_GET_INTEGER(n) / sector_size;
+ break;
+ case QMP_WR_BYTES: /* "wr_bytes" */
+ vbd.wr_sects =
YAJL_GET_INTEGER(n) / sector_size;
+ break;
+ case QMP_RD_OPERATIONS: /*
"rd_operations" */
+ vbd.rd_reqs =
YAJL_GET_INTEGER(n);
+ break;
+ case QMP_WR_OPERATIONS: /*
"wr_operations" */
+ vbd.wr_reqs =
YAJL_GET_INTEGER(n);
+ break;
+ }
+ }
+ }
+ /* With the QMP device name, lookup the xenstore qdisk
device ID and set vdb.dev */
+ if (qmp_devname)
+ get_xs_devid_from_qmp_devname(node, domid,
qmp_devname, &vbd.dev, §or_size, qfd);
+ if ((domain = xenstat_node_domain(node, domid)) == NULL)
+ continue;
+ if ((xenstat_save_vbd(domain, &vbd)) == NULL)
+ goto done;
+ }
+ }
+done:
+ yajl_tree_free(info);
+}
+
+/* Write a command via the QMP */
+static size_t qmp_write(int qfd, char *cmd, size_t cmd_len)
+{
+ size_t pos = 0;
+ ssize_t res;
+
+ while (cmd_len > pos) {
+ res = write(qfd, cmd + pos, cmd_len - pos);
+ switch (res) {
+ case -1:
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ return 0;
+ case 0:
+ errno = EPIPE;
+ return pos;
+ default:
+ pos += (size_t)res;
+ }
+ }
+ return pos;
+}
+
+/* Read the data sent in response to a QMP execute query. Returns 1 for
success */
+static int qmp_read(int qfd, unsigned char **qstats)
+{
+ unsigned char buf[1024], *ptr = NULL;
+ struct pollfd pfd[2];
+ int n, qsize = 0;
+
+ pfd[0].fd = qfd;
+ pfd[0].events = POLLIN;
+ while ((n = poll(pfd, POLLIN, 10)) > 0) {
+ if (pfd[0].revents & POLLIN) {
+ if ((n = read(qfd, buf, sizeof(buf))) < 0) {
+ return 0;
+ }
+ if (ptr == NULL)
+ ptr = malloc(n+1);
+ else
+ ptr = realloc(ptr, qsize+n+1);
+ if (ptr == NULL)
+ return 0;
+ memcpy(&ptr[qsize], buf, n);
+ qsize += n;
+ ptr[qsize] = 0;
+ *qstats = ptr;
+ }
+ }
+ return 1;
+}
+
+/* With the given cmd, query QMP for requested data. Returns allocated buffer
containing data or NULL */
+static unsigned char *qmp_query(int qfd, char *cmd)
+{
+ unsigned char *qstats = NULL;
+ int n;
+
+ n = strlen(cmd);
+ if (qmp_write(qfd, cmd, n) != n)
+ return NULL;
+ if (!qmp_read(qfd, &qstats))
+ return NULL;
+ return qstats;
+}
+
+/* Returns a socket connected to the QMP socket. Returns -1 on failure. */
+static int qmp_connect(char *path)
+{
+ struct sockaddr_un sun;
+ int s;
+
+ if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
+ return -1;
+ (void)fcntl(s, F_SETFD, 1);
+
+ memset(&sun, 0, sizeof(struct sockaddr_un));
+ sun.sun_family = AF_UNIX;
+
+ if (strlen(path) >= sizeof(sun.sun_path)) {
+ close(s);
+ return -1;
+ }
+
+ strcpy(sun.sun_path, path);
+ if (connect(s, (struct sockaddr *)&sun, SUN_LEN(&sun)) < 0) {
+ close(s);
+ return -1;
+ }
+
+ return s;
+}
+
+/* Get all the active domains */
+static xc_domaininfo_t *get_domain_ids(int *num_doms)
+{
+ xc_domaininfo_t *dominfo;
+ xc_interface *xc_handle;
+
+ dominfo = calloc(1024, sizeof(xc_domaininfo_t));
+ if (dominfo == NULL)
+ return NULL;
+ xc_handle = xc_interface_open(0,0,0);
+ *num_doms = xc_domain_getinfolist(xc_handle, 0, 1024, dominfo);
+ xc_interface_close(xc_handle);
+ return dominfo;
+}
+
+/* Gather the qdisk statistics by querying QMP */
+void read_attributes_qdisk(xenstat_node * node)
+{
+ char *cmd_mode = "{ \"execute\": \"qmp_capabilities\" }";
+ char *query_blockstats_cmd = "{ \"execute\": \"query-blockstats\" }";
+ xc_domaininfo_t *dominfo = NULL;
+ unsigned char *qmp_stats, *val;
+ char path[80];
+ int i, qfd, num_doms;
+
+ dominfo = get_domain_ids(&num_doms);
+ if (dominfo == NULL)
+ return;
+
+ for (i=0; i<num_doms; i++) {
+ if (dominfo[i].domain <= 0)
+ continue;
+
+ /* Verify that qdisk disks are used with this VM */
+ snprintf(path, sizeof(path),"/local/domain/0/backend/qdisk/%i",
dominfo[i].domain);
+ if ((val = xs_read(node->handle->xshandle, XBT_NULL, path,
NULL)) == NULL)
+ continue;
+ free(val);
+
+ /* Connect to this VMs QMP socket */
+ snprintf(path, sizeof(path), "/var/run/xen/qmp-libxl-%i",
dominfo[i].domain);
+ if ((qfd = qmp_connect(path)) < 0) {
+ continue;
+ }
+
+ /* First enable QMP capabilities so that we can query for data
*/
+ if ((qmp_stats = qmp_query(qfd, cmd_mode)) != NULL) {
+ free(qmp_stats);
+ /* Query QMP for this VMs blockstats */
+ if ((qmp_stats = qmp_query(qfd, query_blockstats_cmd))
!= NULL) {
+ qmp_parse_stats(node, dominfo[i].domain,
qmp_stats, qfd);
+ free(qmp_stats);
+ }
+ }
+ close(qfd);
+ }
+
+ free(dominfo);
+}
+
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