This patch does a couple of primary things:Firstly it allows you to use "hda", etc. as a path for getting block device stats from fullvirt domains.
Secondly it separates out the stats code into a new file called 'stats_linux.c'. The reasoning behind the name is that this code can be shared between Xen & QEMU, and that the code is Linux-specific (it never worked on Solaris, but now this is explicit). I anticipate a 'stats_solaris.c' file once I can get Solaris + Xen going on a test machine.
Also we try to detect the case where the block dev stats of a fullvirt domain are stuck at 0 -- caused by there being no frontend driver connected. We detect the condition by a query to xenstore.
XENVBD_MAJOR is no longer hard-coded if we can get it instead from Linux header files.
This patch adds bytes written/read to block devices for Xen PV domains if available.
This also corrects a bug where stats from xvdb, xvdc, .. could not be read out because the device number was being miscalculated.
Rich. -- Emerging Technologies, Red Hat - http://et.redhat.com/~rjones/ Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 03798903
Index: src/Makefile.am
===================================================================
RCS file: /data/cvs/libvirt/src/Makefile.am,v
retrieving revision 1.50
diff -u -p -r1.50 Makefile.am
--- src/Makefile.am 19 Sep 2007 17:42:40 -0000 1.50
+++ src/Makefile.am 21 Sep 2007 18:13:31 -0000
@@ -38,6 +38,7 @@ CLIENT_SOURCES = \
xen_internal.c xen_internal.h \
xs_internal.c xs_internal.h \
xend_internal.c xend_internal.h \
+ stats_linux.c stats_linux.h \
sexpr.c sexpr.h \
virterror.c \
driver.h \
@@ -49,8 +50,8 @@ CLIENT_SOURCES = \
iptables.c iptables.h \
uuid.c uuid.h \
qemu_driver.c qemu_driver.h \
- qemu_conf.c qemu_conf.h \
- openvz_conf.c openvz_conf.h \
+ qemu_conf.c qemu_conf.h \
+ openvz_conf.c openvz_conf.h \
openvz_driver.c openvz_driver.h \
nodeinfo.h nodeinfo.c \
util.c util.h
Index: src/stats_linux.c
===================================================================
RCS file: src/stats_linux.c
diff -N src/stats_linux.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ src/stats_linux.c 21 Sep 2007 18:13:31 -0000
@@ -0,0 +1,310 @@
+/*
+ * Linux block and network stats.
+ *
+ * Copyright (C) 2007 Red Hat, Inc.
+ *
+ * See COPYING.LIB for the License of this software
+ *
+ * Richard W.M. Jones <rjones@xxxxxxxxxx>
+ */
+
+#include "config.h"
+
+/* This file only applies on Linux. */
+#ifdef __linux__
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <xs.h>
+
+#include "internal.h"
+#include "xen_unified.h"
+#include "stats_linux.h"
+
+/**
+ * statsErrorFunc:
+ * @error: the error number
+ * @func: the function failing
+ * @info: extra information string
+ * @value: extra information number
+ *
+ * Handle a stats error.
+ */
+static void
+statsErrorFunc(virErrorNumber error, const char *func, const char *info,
+ int value)
+{
+ char fullinfo[1000];
+ const char *errmsg;
+
+ errmsg = __virErrorMsg(error, info);
+ if (func != NULL) {
+ snprintf(fullinfo, 999, "%s: %s", func, info);
+ fullinfo[999] = 0;
+ __virRaiseError(NULL, NULL, NULL, VIR_FROM_XEN, error, VIR_ERR_ERROR,
+ errmsg, fullinfo, NULL, value, 0, errmsg, fullinfo,
+ value);
+ } else {
+ __virRaiseError(NULL, NULL, NULL, VIR_FROM_XEN, error, VIR_ERR_ERROR,
+ errmsg, info, NULL, value, 0, errmsg, info,
+ value);
+ }
+}
+
+#ifdef WITH_XEN
+/*-------------------- Xen: block stats --------------------*/
+
+#include <linux/major.h>
+
+/* This is normally defined in <linux/major.h> but previously we
+ * hard-coded it. So if it's not defined, hard-code again.
+ */
+#ifndef XENVBD_MAJOR
+#define XENVBD_MAJOR 202
+#endif
+
+static int64_t
+read_stat (const char *path)
+{
+ char str[64];
+ int64_t r;
+ int i;
+ FILE *fp;
+
+ fp = fopen (path, "r");
+ if (!fp) return -1;
+ /* stupid GCC warning */ i = fread (str, sizeof str, 1, fp);
+ r = strtoll (str, NULL, 10);
+ fclose (fp);
+ return r;
+}
+
+static int64_t
+read_bd_stat (int device, int domid, const char *str)
+{
+ char path[PATH_MAX];
+ int64_t r;
+
+ snprintf (path, sizeof path,
+ "/sys/devices/xen-backend/vbd-%d-%d/statistics/%s",
+ domid, device, str);
+ r = read_stat (path);
+ if (r >= 0) return r;
+
+ snprintf (path, sizeof path,
+ "/sys/devices/xen-backend/tap-%d-%d/statistics/%s",
+ domid, device, str);
+ r = read_stat (path);
+ return r;
+}
+
+/* In Xenstore, /local/domain/0/backend/vbd/<domid>/<device>/state,
+ * if available, must be XenbusStateConnected (= 4), otherwise there
+ * is no connected device.
+ */
+static int
+check_bd_connected (xenUnifiedPrivatePtr priv, int device, int domid)
+{
+ char s[256], *rs;
+ int r;
+ unsigned len = 0;
+
+ /* This code assumes we're connected if we can't get to
+ * xenstore, etc.
+ */
+ if (!priv->xshandle) return 1;
+ snprintf (s, sizeof s, "/local/domain/0/backend/vbd/%d/%d/state",
+ domid, device);
+ s[sizeof s - 1] = '\0';
+
+ rs = xs_read (priv->xshandle, 0, s, &len);
+ if (!rs) return 1;
+
+ r = STREQ (rs, "4");
+ free (rs);
+ return r;
+}
+
+static int
+read_bd_stats (xenUnifiedPrivatePtr priv,
+ int device, int domid, struct _virDomainBlockStats *stats)
+{
+ stats->rd_req = read_bd_stat (device, domid, "rd_req");
+ stats->rd_bytes = read_bd_stat (device, domid, "rd_sect");
+ stats->wr_req = read_bd_stat (device, domid, "wr_req");
+ stats->wr_bytes = read_bd_stat (device, domid, "wr_sect");
+ stats->errs = read_bd_stat (device, domid, "oo_req");
+
+ /* None of the files were found - it's likely that this version
+ * of Xen is an old one which just doesn't support stats collection.
+ */
+ if (stats->rd_req == -1 && stats->rd_bytes == -1 &&
+ stats->wr_req == -1 && stats->wr_bytes == -1 &&
+ stats->errs == -1) {
+ statsErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
+ "Failed to read any block statistics", domid);
+ return -1;
+ }
+
+ /* If stats are all zero then either there really isn't any block
+ * device activity, or there is no connected front end device
+ * in which case there are no stats.
+ */
+ if (stats->rd_req == 0 && stats->rd_bytes == 0 &&
+ stats->wr_req == 0 && stats->wr_bytes == 0 &&
+ stats->errs == 0 &&
+ !check_bd_connected (priv, device, domid)) {
+ statsErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
+ "Frontend block device not connected", domid);
+ return -1;
+ }
+
+ /* 'Bytes' was really sectors when we read it. Scale up by
+ * an assumed sector size.
+ */
+ if (stats->rd_bytes > 0) stats->rd_bytes *= 512;
+ if (stats->wr_bytes > 0) stats->wr_bytes *= 512;
+
+ return 0;
+}
+
+int
+xenLinuxDomainBlockStats (xenUnifiedPrivatePtr priv,
+ virDomainPtr dom,
+ const char *path,
+ struct _virDomainBlockStats *stats)
+{
+ int minor, device;
+
+ /* Paravirt domains:
+ * Paths have the form "xvd[a-]" and map to paths
+ * /sys/devices/xen-backend/(vbd|tap)-domid-major:minor/
+ * statistics/(rd|wr|oo)_req.
+ * The major:minor is in this case fixed as 202*256 + minor*16
+ * where minor is 0 for xvda, 1 for xvdb and so on.
+ */
+ if (strlen (path) == 4 &&
+ STREQLEN (path, "xvd", 3)) {
+ if ((minor = path[3] - 'a') < 0 || minor > 26) {
+ statsErrorFunc (VIR_ERR_INVALID_ARG, __FUNCTION__,
+ "invalid path, should be xvda, xvdb, etc.",
+ dom->id);
+ return -1;
+ }
+ device = XENVBD_MAJOR * 256 + minor * 16;
+
+ return read_bd_stats (priv, device, dom->id, stats);
+ }
+ /* Fullvirt domains:
+ * hda, hdb etc map to major = HD_MAJOR*256 + minor*16.
+ */
+ else if (strlen (path) == 3 &&
+ STREQLEN (path, "hd", 2)) {
+ if ((minor = path[2] - 'a') < 0 || minor > 26) {
+ statsErrorFunc (VIR_ERR_INVALID_ARG, __FUNCTION__,
+ "invalid path, should be hda, hdb, etc.",
+ dom->id);
+ return -1;
+ }
+ device = HD_MAJOR * 256 + minor * 16;
+
+ return read_bd_stats (priv, device, dom->id, stats);
+ }
+
+ /* Otherwise, unsupported device name. */
+ statsErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
+ "unsupported path (use xvda, hda, etc.)", dom->id);
+ return -1;
+}
+
+#endif /* WITH_XEN */
+
+/*-------------------- interface stats --------------------*/
+/* Just reads the named interface, so not Xen or QEMU-specific.
+ * NB. Caller must check that libvirt user is trying to query
+ * the interface of a domain they own. We do no such checking.
+ */
+
+int
+linuxDomainInterfaceStats (const char *path,
+ struct _virDomainInterfaceStats *stats)
+{
+ int path_len;
+ FILE *fp;
+ char line[256];
+
+ fp = fopen ("/proc/net/dev", "r");
+ if (!fp) {
+ statsErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
+ "/proc/net/dev", errno);
+ return -1;
+ }
+
+ path_len = strlen (path);
+
+ while (fgets (line, sizeof line, fp)) {
+ long long dummy;
+ long long rx_bytes;
+ long long rx_packets;
+ long long rx_errs;
+ long long rx_drop;
+ long long tx_bytes;
+ long long tx_packets;
+ long long tx_errs;
+ long long tx_drop;
+
+ if (STREQLEN (line, path, path_len) &&
+ line[path_len] == ':' &&
+ line[path_len+1] == ' ') {
+ /* IMPORTANT NOTE!
+ * /proc/net/dev vif<domid>.nn sees the network from the point
+ * of view of dom0 / hypervisor. So bytes TRANSMITTED by dom0
+ * are bytes RECEIVED by the domain. That's why the TX/RX fields
+ * appear to be swapped here.
+ */
+ if (sscanf (&line[path_len+2],
+ "%lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld",
+ &tx_bytes, &tx_packets, &tx_errs, &tx_drop,
+ &dummy, &dummy, &dummy, &dummy,
+ &rx_bytes, &rx_packets, &rx_errs, &rx_drop,
+ &dummy, &dummy, &dummy, &dummy) != 16)
+ continue;
+
+ stats->rx_bytes = rx_bytes;
+ stats->rx_packets = rx_packets;
+ stats->rx_errs = rx_errs;
+ stats->rx_drop = rx_drop;
+ stats->tx_bytes = tx_bytes;
+ stats->tx_packets = tx_packets;
+ stats->tx_errs = tx_errs;
+ stats->tx_drop = tx_drop;
+ fclose (fp);
+
+ return 0;
+ }
+ }
+ fclose (fp);
+
+ statsErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
+ "/proc/net/dev: Interface not found", 0);
+ return -1;
+}
+
+#endif /* __linux__ */
+/*
+ * vim: set tabstop=4:
+ * vim: set shiftwidth=4:
+ * vim: set expandtab:
+ */
+/*
+ * Local variables:
+ * indent-tabs-mode: nil
+ * c-indent-level: 4
+ * c-basic-offset: 4
+ * tab-width: 4
+ * End:
+ */
Index: src/stats_linux.h
===================================================================
RCS file: src/stats_linux.h
diff -N src/stats_linux.h
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ src/stats_linux.h 21 Sep 2007 18:13:31 -0000
@@ -0,0 +1,39 @@
+/*
+ * Linux block and network stats.
+ *
+ * Copyright (C) 2007 Red Hat, Inc.
+ *
+ * See COPYING.LIB for the License of this software
+ *
+ * Richard W.M. Jones <rjones@xxxxxxxxxx>
+ */
+
+#ifndef __STATS_LINUX_H__
+#define __STATS_LINUX_H__
+
+#ifdef __linux__
+
+#include "xen_unified.h"
+
+extern int xenLinuxDomainBlockStats (xenUnifiedPrivatePtr priv,
+ virDomainPtr dom, const char *path,
+ struct _virDomainBlockStats *stats);
+extern int linuxDomainInterfaceStats (const char *path,
+ struct _virDomainInterfaceStats *stats);
+
+#endif /* __linux__ */
+
+#endif /* __STATS_LINUX_H__ */
+/*
+ * vim: set tabstop=4:
+ * vim: set shiftwidth=4:
+ * vim: set expandtab:
+ */
+/*
+ * Local variables:
+ * indent-tabs-mode: nil
+ * c-indent-level: 4
+ * c-basic-offset: 4
+ * tab-width: 4
+ * End:
+ */
Index: src/xen_internal.c
===================================================================
RCS file: /data/cvs/libvirt/src/xen_internal.c,v
retrieving revision 1.94
diff -u -p -r1.94 xen_internal.c
--- src/xen_internal.c 29 Aug 2007 13:35:15 -0000 1.94
+++ src/xen_internal.c 21 Sep 2007 18:13:33 -0000
@@ -27,7 +27,9 @@
#include <regex.h>
#include <errno.h>
#include <sys/utsname.h>
+
#include "xs_internal.h"
+#include "stats_linux.h"
/* required for dom0_getdomaininfo_t */
#include <xen/dom0_ops.h>
@@ -1306,74 +1308,23 @@ xenHypervisorSetSchedulerParameters(virD
return 0;
}
-static int64_t
-read_stat (const char *path)
-{
- char str[64];
- int64_t r;
- int i;
- FILE *fp;
- fp = fopen (path, "r");
- if (!fp) return -1;
- /* stupid GCC warning */ i = fread (str, sizeof str, 1, fp);
- r = strtoll (str, NULL, 10);
- fclose (fp);
- return r;
-}
-
-static int64_t
-read_bd_stat (int device, int domid, const char *str)
-{
- char path[PATH_MAX];
- int64_t r;
-
- snprintf (path, sizeof path,
- "/sys/devices/xen-backend/vbd-%d-%d/statistics/%s_req",
- domid, device, str);
- r = read_stat (path);
- if (r >= 0) return r;
-
- snprintf (path, sizeof path,
- "/sys/devices/xen-backend/tap-%d-%d/statistics/%s_req",
- domid, device, str);
- r = read_stat (path);
- return r;
-}
-
-/* Paths have the form "xvd[a-]" and map to paths /sys/devices/xen-backend/
- * (vbd|tap)-domid-major:minor/statistics/(rd|wr|oo)_req. The major:minor
- * is in this case fixed as 202*256 + 16*minor where minor is 0 for xvda,
- * 1 for xvdb and so on.
- */
int
xenHypervisorDomainBlockStats (virDomainPtr dom,
const char *path,
struct _virDomainBlockStats *stats)
{
- int minor, device;
-
- if (strlen (path) != 4 ||
- STRNEQLEN (path, "xvd", 3) ||
- (minor = path[3] - 'a') < 0 ||
- minor > 26) {
- virXenErrorFunc (VIR_ERR_INVALID_ARG, __FUNCTION__,
- "invalid path, should be xvda, xvdb, etc.", 0);
- return -1;
- }
- device = 202 * 256 + minor;
-
- stats->rd_req = read_bd_stat (device, dom->id, "rd");
- stats->wr_req = read_bd_stat (device, dom->id, "wr");
- stats->errs = read_bd_stat (device, dom->id, "oo");
-
- if (stats->rd_req == -1 && stats->wr_req == -1 && stats->errs == -1) {
- virXenErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
- "Failed to read any block statistics", dom->id);
- return -1;
- }
+#ifdef __linux__
+ xenUnifiedPrivatePtr priv;
- return 0;
+ priv = (xenUnifiedPrivatePtr) dom->conn->privateData;
+ return xenLinuxDomainBlockStats (priv, dom, path, stats);
+#else
+ virXenErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
+ "block statistics not supported on this platform",
+ dom->id);
+ return -1;
+#endif
}
/* Paths have the form vif<domid>.<n> (this interface checks that
@@ -1382,19 +1333,18 @@ xenHypervisorDomainBlockStats (virDomain
* In future we may allow you to query bridge stats (virbrX or
* xenbrX), but that will probably be through a separate
* virNetwork interface, as yet not decided.
- *
- * On Linux we open /proc/net/dev and look for the device
- * called vif<domid>.<n>.
*/
int
xenHypervisorDomainInterfaceStats (virDomainPtr dom,
const char *path,
struct _virDomainInterfaceStats *stats)
{
+#ifdef __linux__
int rqdomid, device;
- FILE *fp;
- char line[256];
+ /* Verify that the vif requested is one belonging to the current
+ * domain.
+ */
if (sscanf (path, "vif%d.%d", &rqdomid, &device) != 2) {
virXenErrorFunc (VIR_ERR_INVALID_ARG, __FUNCTION__,
"invalid path, should be vif<domid>.<n>.", 0);
@@ -1406,56 +1356,12 @@ xenHypervisorDomainInterfaceStats (virDo
return -1;
}
- fp = fopen ("/proc/net/dev", "r");
- if (!fp) {
- virXenErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
- "/proc/net/dev", errno);
- return -1;
- }
- while (fgets (line, sizeof line, fp)) {
- int domid, port;
- long long dummy;
- long long rx_bytes;
- long long rx_packets;
- long long rx_errs;
- long long rx_drop;
- long long tx_bytes;
- long long tx_packets;
- long long tx_errs;
- long long tx_drop;
-
- /* IMPORTANT NOTE!
- * /proc/net/dev vif<domid>.nn sees the network from the point
- * of view of dom0 / hypervisor. So bytes TRANSMITTED by dom0
- * are bytes RECEIVED by the domain. That's why the TX/RX fields
- * appear to be swapped here.
- */
- if (sscanf (line, "vif%d.%d: %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld %lld",
- &domid, &port,
- &tx_bytes, &tx_packets, &tx_errs, &tx_drop,
- &dummy, &dummy, &dummy, &dummy,
- &rx_bytes, &rx_packets, &rx_errs, &rx_drop,
- &dummy, &dummy, &dummy, &dummy) != 18)
- continue;
-
- if (domid == dom->id && port == device) {
- stats->rx_bytes = rx_bytes;
- stats->rx_packets = rx_packets;
- stats->rx_errs = rx_errs;
- stats->rx_drop = rx_drop;
- stats->tx_bytes = tx_bytes;
- stats->tx_packets = tx_packets;
- stats->tx_errs = tx_errs;
- stats->tx_drop = tx_drop;
- fclose (fp);
- return 0;
- }
- }
- fclose (fp);
-
+ return linuxDomainInterfaceStats (path, stats);
+#else
virXenErrorFunc (VIR_ERR_NO_SUPPORT, __FUNCTION__,
"/proc/net/dev: Interface not found", 0);
return -1;
+#endif
}
/**
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