[PATCH 6/6] xl: 'xl claims' print outstanding per domain claims if enabled (claim_mode=1 in xl.conf)

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

This is similar to "xl: 'xl info' print outstanding claims if enabled
(claim_mode=1 in xl.conf)" which exposes the global claim value.

This patch provides the value of the currently outstanding pages
claimed for each domains. This is per domain value which is added
to the global claim value which influences the hypervisors' MM system.

When a claim call is done, a reservation for a specific amount of pages
is set (and this patch lists said number) and also a global value is
incremented. This global value is then reduced as the domain's memory
is populated and eventually reaches zero.

The toolstack (libxc) also sets the domain's claim to zero when the population
of memory has completed as an extra step. Any call to destroy the domain
will also set the domain's claim to zero.

If the reservation cannot be meet the guest creation fails immediately
instead of taking seconds or minutes (depending on the size of the guest)
while the toolstack populates memory.

See patch: "xl: Implement XENMEM_claim_pages support via 'claim_mode'
global config" for details on how it is implemented.

The value fluctuates quite often so the value is stale once it is provided
to the user-space.  However it is useful for diagnostic purposes.

It is only printed when the global "claim_mode" option in xl.conf(5)
is set to enabled (1). The 'man xl' shows the details of this item.
The output is close to what 'xl list' looks like:

Name                                        ID   Mem VCPUs      State   Time(s)  Claim
Domain-0                                     0  2048     4     r-----      15.7     0
OL5                                          2   321     1     --p---       0.0  1717
OL6                                          3   217     1     --p---       0.0   797

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 docs/man/xl.pod.1         | 17 +++++++++++++++++
 tools/libxl/xl.h          |  1 +
 tools/libxl/xl_cmdimpl.c  | 35 +++++++++++++++++++++++++++++++++--
 tools/libxl/xl_cmdtable.c |  6 ++++++
 4 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/docs/man/xl.pod.1 b/docs/man/xl.pod.1
index d8783e8..18415b1 100644
--- a/docs/man/xl.pod.1
+++ b/docs/man/xl.pod.1
@@ -780,6 +780,23 @@ explanatory.
 
 Prints the current uptime of the domains running.
 
+=item B<claim-list>
+
+Prints information about outstanding claims by the guests. This provides the
+per-domain outstanding claims and memory allocated to the guests. These
+values added up reflect the global outstanding claim information provided via
+the I<info> argument, B<outstanding_claims> value.
+
+B<EXAMPLE>
+
+An example format for the list is as follows:
+
+ Name                                        ID   Mem VCPUs      State   Time(s)  Claim
+ Domain-0                                     0  2047     4     r-----      19.7     0
+ OL5                                          2  1191     1     --p---       0.0   847
+ OL6                                          3  1024     4     r-----       5.9     0
+ Windows_XP                                   4    49     1     --p---       0.0  1989
+
 =back
 
 =head1 SCHEDULER SUBCOMMANDS
diff --git a/tools/libxl/xl.h b/tools/libxl/xl.h
index 4c5e5d1..771b4af 100644
--- a/tools/libxl/xl.h
+++ b/tools/libxl/xl.h
@@ -83,6 +83,7 @@ int main_vtpmattach(int argc, char **argv);
 int main_vtpmlist(int argc, char **argv);
 int main_vtpmdetach(int argc, char **argv);
 int main_uptime(int argc, char **argv);
+int main_claims(int argc, char **argv);
 int main_tmem_list(int argc, char **argv);
 int main_tmem_freeze(int argc, char **argv);
 int main_tmem_thaw(int argc, char **argv);
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index c9b71e6..f702aaf 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -3061,7 +3061,8 @@ out:
     }
 }
 
-static void list_domains(int verbose, int context, const libxl_dominfo *info, int nb_domain)
+static void list_domains(int verbose, int context, int claim,
+                         const libxl_dominfo *info, int nb_domain)
 {
     int i;
     static const char shutdown_reason_letters[]= "-rscw";
@@ -3069,6 +3070,7 @@ static void list_domains(int verbose, int context, const libxl_dominfo *info, in
     printf("Name                                        ID   Mem VCPUs\tState\tTime(s)");
     if (verbose) printf("   UUID                            Reason-Code\tSecurity Label");
     if (context && !verbose) printf("   Security Label");
+    if (claim) printf("  Claim");
     printf("\n");
     for (i = 0; i < nb_domain; i++) {
         char *domname;
@@ -3095,6 +3097,8 @@ static void list_domains(int verbose, int context, const libxl_dominfo *info, in
             if (info[i].shutdown) printf(" %8x", shutdown_reason);
             else printf(" %8s", "-");
         }
+        if (claim)
+            printf(" %5lu", (unsigned long)info[i].outstanding_memkb / 1024);
         if (verbose || context) {
             int rc;
             size_t size;
@@ -4029,7 +4033,7 @@ int main_list(int argc, char **argv)
     if (details)
         list_domains_details(info, nb_domain);
     else
-        list_domains(verbose, context, info, nb_domain);
+        list_domains(verbose, context, 0 /* claim */, info, nb_domain);
 
     if (info_free)
         libxl_dominfo_list_free(info, nb_domain);
@@ -5927,6 +5931,33 @@ static char *uptime_to_string(unsigned long uptime, int short_mode)
     return time_string;
 }
 
+int main_claims(int argc, char **argv)
+{
+    libxl_dominfo *info;
+    int opt;
+    int nb_domain;
+
+    SWITCH_FOREACH_OPT(opt, "", NULL, "claims", 0) {
+        /* No options */
+    }
+
+    if (!libxl_defbool_val(claim_mode)) {
+        fprintf(stderr, "claim_mode not enabled (see man xl.conf).\n");
+        return 1;
+    }
+    info = libxl_list_domain(ctx, &nb_domain);
+    if (!info) {
+        fprintf(stderr, "libxl_domain_infolist failed.\n");
+        return 1;
+    }
+
+    list_domains(0 /* verbose */, 0 /* context */, 1 /* claim */,
+                 info, nb_domain);
+
+    libxl_dominfo_list_free(info, nb_domain);
+    return 0;
+}
+
 static char *current_time_to_string(time_t now)
 {
     char now_str[100];
diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index b4a87ca..00899f5 100644
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -362,6 +362,12 @@ struct cmd_spec cmd_table[] = {
       "Print uptime for all/some domains",
       "[-s] [Domain]",
     },
+    { "claims",
+      &main_claims, 0, 0,
+      "List outstanding claim information about all domains",
+      "",
+      "",
+    },
     { "tmem-list",
       &main_tmem_list, 0, 0,
       "List tmem pools",
-- 
1.8.1.4