[libvirt] [PATCH] Cope with missing swap cgroup controls

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

It is possible to build a kernel without swap cgroup controls
present. This causes a fatal error when querying memory
parameters. Treat missing swap controls as meaning "unlimited".
The fatal error remains if the user tries to actually change
the limit.

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 src/qemu/qemu_driver.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 6a23573..693b637 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -7612,9 +7612,12 @@ qemuDomainGetMemoryParameters(virDomainPtr dom,
         case 2: /* fill swap hard limit here */
             rc = virCgroupGetMemSwapHardLimit(priv->cgroup, &val);
             if (rc != 0) {
-                virReportSystemError(-rc, "%s",
-                                     _("unable to get swap hard limit"));
-                goto cleanup;
+                if (rc != -ENOENT) {
+                    virReportSystemError(-rc, "%s",
+                                         _("unable to get swap hard limit"));
+                    goto cleanup;
+                }
+                val = VIR_DOMAIN_MEMORY_PARAM_UNLIMITED;
             }
             if (virTypedParameterAssign(param,
                                         VIR_DOMAIN_MEMORY_SWAP_HARD_LIMIT,
-- 
1.8.2.1