[Intel-gfx] [PATCH] lib: adjust oom_score

[Daniel Vetter]

This way the igt test will always be killed first (hopefully),
preventing mayhem when one of the memory thrashing tests treatens to
take down the entire system.

To avoid any burden on test writers we adjust the oom score on
drm_open, any of the fork helpers and subtest init. That should cover
everything.

Cc: Ben Widawsky <ben at bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 lib/drmtest.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/lib/drmtest.c b/lib/drmtest.c
index d8fc60f656e4..7f13e0561935 100644
--- a/lib/drmtest.c
+++ b/lib/drmtest.c
@@ -203,6 +203,15 @@ int drm_get_card(void)
 	return -1;
 }
 
+static void oom_adjust_for_doom(void)
+{
+	int fd;
+	const char always_kill[] = "1000";
+
+	igt_assert(fd = open("/proc/self/oom_adj", O_WRONLY) != -1);
+	igt_assert(write(fd, always_kill, sizeof(always_kill)) == sizeof(always_kill));
+}
+
 /** Open the first DRM device we can find, searching up to 16 device nodes */
 static int __drm_open_any(void)
 {
@@ -221,6 +230,8 @@ static int __drm_open_any(void)
 		fd = -1;
 	}
 
+	oom_adjust_for_doom();
+
 	return fd;
 }
 
@@ -250,6 +261,8 @@ static int __drm_open_any_render(void)
 		return fd;
 	}
 
+	oom_adjust_for_doom();
+
 	return fd;
 }
 
@@ -843,6 +856,7 @@ int igt_subtest_init_parse_opts(int argc, char **argv,
 	}
 
 	igt_install_exit_handler(check_igt_exit);
+	oom_adjust_for_doom();
 
 out:
 	return ret;
@@ -1114,6 +1128,7 @@ bool __igt_fork_helper(struct igt_helper_process *proc)
 	case 0:
 		exit_handler_count = 0;
 		reset_helper_process_list();
+		oom_adjust_for_doom();
 
 		return true;
 	default:
@@ -1196,6 +1211,7 @@ bool __igt_fork(void)
 		test_child = true;
 		exit_handler_count = 0;
 		reset_helper_process_list();
+		oom_adjust_for_doom();
 
 		return true;
 	default:
-- 
1.8.1.4