[libvirt] [PATCH v2] libvirtd: Increase NL buffer size for lots of interface

[Leno Hou]

1. When switching CPUs to offline/online in a system more than 128 cpus
2. When using virsh to destroy domain in a system with more interface

All of above happens nl_recv returned with error: No buffer space available.
This patch sets the socket buffer size to 128K and turns on message peeking
for nl_recv,as this would solve this problem totally and permanetly.

Signed-off-by: Leno Hou <houqy at linux.vnet.ibm.com>
Cc: Wenyi Gao <wenyi at linux.vnet.ibm.com>
CC: Laine Stump <laine at laine.org>
CC: Michal Privoznik <mprivozn at redhat.com>
---
 src/util/virnetlink.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/util/virnetlink.c b/src/util/virnetlink.c
index 679b48e..2f2691c 100644
--- a/src/util/virnetlink.c
+++ b/src/util/virnetlink.c
@@ -65,10 +65,12 @@ struct virNetlinkEventHandle {
 
 # ifdef HAVE_LIBNL1
 #  define virNetlinkAlloc nl_handle_alloc
+#  define virSocketSetBufferSize nl_set_buffer_size
 #  define virNetlinkFree nl_handle_destroy
 typedef struct nl_handle virNetlinkHandle;
 # else
 #  define virNetlinkAlloc nl_socket_alloc
+#  define virSocketSetBufferSize nl_socket_buffer_size
 #  define virNetlinkFree nl_socket_free
 typedef struct nl_sock virNetlinkHandle;
 # endif
@@ -696,6 +698,14 @@ virNetlinkEventServiceStart(unsigned int protocol, unsigned int groups)
         goto error_server;
     }
 
+    if (virSocketSetBufferSize(srv->netlinknh, 131702, 0) < 0) {
+        virReportSystemError(errno,
+                "%s",_("cannot set netlink socket buffer size to 128k"));
+        goto error_server;
+    }
+
+    nl_socket_enable_msg_peek(srv->netlinknh);
+
     if ((srv->eventwatch = virEventAddHandle(fd,
                                              VIR_EVENT_HANDLE_READABLE,
                                              virNetlinkEventCallback,
-- 
1.9.1