2 files changed, 20 insertions, 6 deletions

diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index e96a341eb7e4..1d192565e182 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -197,11 +197,22 @@ and may not be fast.
 
 panic_on_oom
 
-This enables or disables panic on out-of-memory feature.  If this is set to 1,
-the kernel panics when out-of-memory happens.  If this is set to 0, the kernel
-will kill some rogue process, called oom_killer.  Usually, oom_killer can kill
-rogue processes and system will survive.  If you want to panic the system
-rather than killing rogue processes, set this to 1.
+This enables or disables panic on out-of-memory feature.
 
-The default value is 0.
+If this is set to 0, the kernel will kill some rogue process,
+called oom_killer.  Usually, oom_killer can kill rogue processes and
+system will survive.
+
+If this is set to 1, the kernel panics when out-of-memory happens.
+However, if a process limits using nodes by mempolicy/cpusets,
+and those nodes become memory exhaustion status, one process
+may be killed by oom-killer. No panic occurs in this case.
+Because other nodes' memory may be free. This means system total status
+may be not fatal yet.
 
+If this is set to 2, the kernel panics compulsorily even on the
+above-mentioned.
+
+The default value is 0.
+1 and 2 are for failover of clustering. Please select either
+according to your policy of failover.
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index a35e7a8ebd7e..038d2234f139 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -413,6 +413,9 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
                 show_mem();
         }
 
+        if (sysctl_panic_on_oom == 2)
+                panic("out of memory. Compulsory panic_on_oom is selected.\n");
+
         cpuset_lock();
         read_lock(&tasklist_lock);