mm, oom: Modify default value of panic_on_oom

If a userspace low memory killer is present, the kernel oom killer
is not expected to be invoked. Therefore, trigger a reset on any
such occurrence.

Change-Id: I7f3451e9c4deb843b3e4dfa13e9764101e90b8ae
Signed-off-by: Patrick Daly <pdaly@codeaurora.org>

mm/Kconfig.debug

@@ -41,6 +41,14 @@ config SLUB_DEBUG_PANIC_ON
 	  investigating the root cause which may be rooted within cache
 	  or memory.
 
+config DEBUG_PANIC_ON_OOM
+	bool "Enable to Panic on OOM detection"
+	help
+	  Android primarily uses an alternative mechanism to detect low
+	  memory situations and kill processes as required. The kernel
+	  oom-killer can mask problems with this feature, which may be
+	  undesireable in a debug environment.
+
 config DEBUG_PAGEALLOC_ENABLE_DEFAULT
 	bool "Enable debug page memory allocations by default?"
 	default n

mm/oom_kill.c

@@ -51,7 +51,8 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/oom.h>
 
-int sysctl_panic_on_oom;
+int sysctl_panic_on_oom =
+IS_ENABLED(CONFIG_DEBUG_PANIC_ON_OOM) ? 2 : 0;
 int sysctl_oom_kill_allocating_task;
 int sysctl_oom_dump_tasks = 1;
 int sysctl_reap_mem_on_sigkill;