ipc: scale msgmni to the amount of lowmem

[mv-sheeva.git] / ipc / msg.c

diff --git a/ipc/msg.c b/ipc/msg.c
index 805ee08ec8bbb87259cfe60dac70b698068a59d5..9e7211122e27eb5b8dd8772a13193a4dd076a046 100644 (file)
--- 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]);