ipc: scale msgmni to the number of ipc namespaces

Since all the namespaces see the same amount of memory (the total one) this patch introduces a new variable that counts the ipc namespaces and divides msg_ctlmni by this counter. Signed-off-by: Nadia Derbey <[email protected]> Cc: Yasunori Goto <[email protected]> Cc: Matt Helsley <[email protected]> Cc: Mingming Cao <[email protected]> Cc: Pierre Peiffer <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
yshchan · Apr 29, 2008 · 4d89dc6 · 4d89dc6
1 parent f7bf3df
commit 4d89dc6
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Showing 4 changed files with 14 additions and 3 deletions.
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
@@ -33,6 +33,7 @@ struct ipc_namespace {
 };
 
 extern struct ipc_namespace init_ipc_ns;
+extern atomic_t nr_ipc_ns;
 
 #ifdef CONFIG_SYSVIPC
 #define INIT_IPC_NS(ns)		.ns		= &init_ipc_ns,

diff --git a/ipc/msg.c b/ipc/msg.c
@@ -81,24 +81,28 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 /*
  * 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.
+ * Also take into account the number of nsproxies created so far.
+ * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
  */
 static void recompute_msgmni(struct ipc_namespace *ns)
 {
 	struct sysinfo i;
 	unsigned long allowed;
+	int nb_ns;
 
 	si_meminfo(&i);
 	allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
 		/ MSGMNB;
+	nb_ns = atomic_read(&nr_ipc_ns);
+	allowed /= nb_ns;
 
 	if (allowed < MSGMNI) {
 		ns->msg_ctlmni = MSGMNI;
 		goto out_callback;
 	}
 
-	if (allowed > IPCMNI) {
-		ns->msg_ctlmni = IPCMNI;
+	if (allowed > IPCMNI / nb_ns) {
+		ns->msg_ctlmni = IPCMNI / nb_ns;
 		goto out_callback;
 	}
 

diff --git a/ipc/namespace.c b/ipc/namespace.c
@@ -20,6 +20,8 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns)
 	if (ns == NULL)
 		return ERR_PTR(-ENOMEM);
 
+	atomic_inc(&nr_ipc_ns);
+
 	sem_init_ns(ns);
 	msg_init_ns(ns);
 	shm_init_ns(ns);
@@ -83,4 +85,5 @@ void free_ipc_ns(struct kref *kref)
 	msg_exit_ns(ns);
 	shm_exit_ns(ns);
 	kfree(ns);
+	atomic_dec(&nr_ipc_ns);
 }
diff --git a/ipc/util.c b/ipc/util.c
@@ -52,6 +52,9 @@ struct ipc_namespace init_ipc_ns = {
 	},
 };
 
+atomic_t nr_ipc_ns = ATOMIC_INIT(1);
+
+
 /**
  *	ipc_init	-	initialise IPC subsystem
  *
-Original file line number
+Diff line change
@@ Expand Up / @@ -52,6 +52,9 @@ struct ipc_namespace init_ipc_ns = { @@
     	},
     };
+    atomic_t nr_ipc_ns = ATOMIC_INIT(1);
     /**
      *	ipc_init	-	initialise IPC subsystem
      *
@@ Expand Down @@