File tools-utility-to-dump-guest-grant-table-info.patch of Package xen
From: Dongli Zhang <dongli.zhang@oracle.com>
Date: Mon, 3 Jul 2017 07:34:13 +0800
Subject: tools: utility to dump guest grant table info
Patch-mainline: 4.10.0-rc1
Git-commit: df36d82e3fc91bee2ff1681fd438c815fa324b6a
As both xen-netfront and xen-blkfront support multi-queue, they would
consume a lot of grant table references when there are many paravirtual
devices and vcpus assigned to guest. Guest domU might panic or hang due to
grant allocation failure when nr_grant_frames in guest has reached its max
value.
This utility would help the administrators to diagnose xen issue. There is
only one command gnttab_query_size so far to monitor the guest grant table
frame usage on dom0 side so that it is not required to debug on guest
kernel side for crash/hang analysis anymore.
It is extensible for adding new commands for more diagnostic functions and
the framework of xen-diag.c is from xen-livepatch.c.
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---
tools/misc/Makefile | 4 ++
tools/misc/xen-diag.c | 129 ++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 133 insertions(+)
create mode 100644 tools/misc/xen-diag.c
--- a/tools/misc/Makefile
+++ b/tools/misc/Makefile
@@ -31,6 +31,7 @@ INSTALL_SBIN += xenper
INSTALL_SBIN += xenpm
INSTALL_SBIN += xenwatchdogd
INSTALL_SBIN += xen-livepatch
+INSTALL_SBIN += xen-diag
INSTALL_SBIN += $(INSTALL_SBIN-y)
# Everything to be installed in a private bin/
@@ -102,6 +103,9 @@ xenwatchdogd: xenwatchdogd.o
xen-livepatch: xen-livepatch.o
$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+xen-diag: xen-diag.o
+ $(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenctrl) $(APPEND_LDFLAGS)
+
xen-lowmemd: xen-lowmemd.o
$(CC) $(LDFLAGS) -o $@ $< $(LDLIBS_libxenevtchn) $(LDLIBS_libxenctrl) $(LDLIBS_libxenstore) $(APPEND_LDFLAGS)
--- /dev/null
+++ b/tools/misc/xen-diag.c
@@ -0,0 +1,129 @@
+/*
+ * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <err.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <xenctrl.h>
+
+#include <xen/errno.h>
+#include <xen-tools/libs.h>
+
+static xc_interface *xch;
+
+#define ARRAY_SIZE(a) (sizeof (a) / sizeof ((a)[0]))
+
+void show_help(void)
+{
+ fprintf(stderr,
+ "xen-diag: xen diagnostic utility\n"
+ "Usage: xen-diag command [args]\n"
+ "Commands:\n"
+ " help display this help\n"
+ " gnttab_query_size <domid> dump the current and max grant frames for <domid>\n");
+}
+
+/* wrapper function */
+static int help_func(int argc, char *argv[])
+{
+ show_help();
+ return 0;
+}
+
+static int gnttab_query_size_func(int argc, char *argv[])
+{
+ int domid, rc = 1;
+ struct gnttab_query_size query;
+
+ if ( argc != 1 )
+ {
+ show_help();
+ return rc;
+ }
+
+ domid = strtol(argv[0], NULL, 10);
+ query.dom = domid;
+ rc = xc_gnttab_query_size(xch, &query);
+
+ if ( rc == 0 && (query.status == GNTST_okay) )
+ printf("domid=%d: nr_frames=%d, max_nr_frames=%d\n",
+ query.dom, query.nr_frames, query.max_nr_frames);
+
+ return rc == 0 && (query.status == GNTST_okay) ? 0 : 1;
+}
+
+struct {
+ const char *name;
+ int (*function)(int argc, char *argv[]);
+} main_options[] = {
+ { "help", help_func },
+ { "gnttab_query_size", gnttab_query_size_func},
+};
+
+int main(int argc, char *argv[])
+{
+ int ret, i;
+
+ /*
+ * Set stdout to be unbuffered to avoid having to fflush when
+ * printing without a newline.
+ */
+ setvbuf(stdout, NULL, _IONBF, 0);
+
+ if ( argc <= 1 )
+ {
+ show_help();
+ return 0;
+ }
+
+ for ( i = 0; i < ARRAY_SIZE(main_options); i++ )
+ if ( !strncmp(main_options[i].name, argv[1], strlen(argv[1])) )
+ break;
+
+ if ( i == ARRAY_SIZE(main_options) )
+ {
+ show_help();
+ return 0;
+ }
+ else
+ {
+ xch = xc_interface_open(0, 0, 0);
+ if ( !xch )
+ {
+ fprintf(stderr, "failed to get the handler\n");
+ return 0;
+ }
+
+ ret = main_options[i].function(argc - 2, argv + 2);
+
+ xc_interface_close(xch);
+ }
+
+ /*
+ * Exitcode 0 for success.
+ * Exitcode 1 for an error.
+ * Exitcode 2 if the operation should be retried for any reason (e.g. a
+ * timeout or because another operation was in progress).
+ */
+
+#define EXIT_TIMEOUT (EXIT_FAILURE + 1)
+
+ BUILD_BUG_ON(EXIT_SUCCESS != 0);
+ BUILD_BUG_ON(EXIT_FAILURE != 1);
+ BUILD_BUG_ON(EXIT_TIMEOUT != 2);
+
+ switch ( ret )
+ {
+ case 0:
+ return EXIT_SUCCESS;
+ case EAGAIN:
+ case EBUSY:
+ return EXIT_TIMEOUT;
+ default:
+ return EXIT_FAILURE;
+ }
+}
