Add option to mlock qemu and guest memory

In certain scenario, latency induced by paging is significant and
memory locking is needed. Also, in the scenario with untrusted
guests, latency improvement due to mlock is desired.

This patch introduces a following new option to mlock guest and
qemu memory:

-realtime mlock=on|off

Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1366382526-26146-1-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/os-posix.c b/os-posix.c
index 5c64518902..d39261d849 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -363,3 +363,15 @@ bool is_daemonized(void)
 {
     return daemonize;
 }
+
+int os_mlock(void)
+{
+    int ret = 0;
+
+    ret = mlockall(MCL_CURRENT | MCL_FUTURE);
+    if (ret < 0) {
+        perror("mlockall");
+    }
+
+    return ret;
+}