1 files changed, 36 insertions, 1 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
index 805ee08ec8bb..9e7211122e27 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -27,6 +27,7 @@
 #include <linux/msg.h>
 #include <linux/spinlock.h>
 #include <linux/init.h>
+#include <linux/mm.h>
 #include <linux/proc_fs.h>
 #include <linux/list.h>
 #include <linux/security.h>
@@ -77,11 +78,45 @@ static int newque(struct ipc_namespace *, struct ipc_params *);
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif
 
+/*
+ * Scale msgmni with the available lowmem size: the memory dedicated to msg
+ * queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
+ * This should be done staying within the (MSGMNI , IPCMNI) range.
+ */
+static void recompute_msgmni(struct ipc_namespace *ns)
+{
+        struct sysinfo i;
+        unsigned long allowed;
+
+        si_meminfo(&i);
+        allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
+                / MSGMNB;
+
+        if (allowed < MSGMNI) {
+                ns->msg_ctlmni = MSGMNI;
+                goto out_callback;
+        }
+
+        if (allowed > IPCMNI) {
+                ns->msg_ctlmni = IPCMNI;
+                goto out_callback;
+        }
+
+        ns->msg_ctlmni = allowed;
+
+out_callback:
+
+        printk(KERN_INFO "msgmni has been set to %d for ipc namespace %p\n",
+                ns->msg_ctlmni, ns);
+}
+
 void msg_init_ns(struct ipc_namespace *ns)
 {
         ns->msg_ctlmax = MSGMAX;
         ns->msg_ctlmnb = MSGMNB;
-        ns->msg_ctlmni = MSGMNI;
+
+        recompute_msgmni(ns);
+
         atomic_set(&ns->msg_bytes, 0);
         atomic_set(&ns->msg_hdrs, 0);
         ipc_init_ids(&ns->ids[IPC_MSG_IDS]);