[PATCH 2/4] oom: take per file badness into account

Andrey Grodzovsky
2018-01-18T16:49:08Z

Try to make better decisions which process to kill based on
per file OOM badness

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
---
mm/oom_kill.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 29f8555..825ed52 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -49,6 +49,8 @@
#define CREATE_TRACE_POINTS
#include <trace/events/oom.h>

+#include <linux/fdtable.h>
+
int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
int sysctl_oom_dump_tasks = 1;
@@ -182,6 +184,21 @@ static bool is_dump_unreclaim_slabs(void)
}

/**
+ * oom_file_badness - add per file badness
+ * @points: pointer to summed up badness points
+ * @file: tasks open file
+ * @n: file descriptor id (unused)
+ */
+static int oom_file_badness(const void *points, struct file *file, unsigned n)
+{
+ if (file->f_op->oom_file_badness)
+ *((long *)points) += file->f_op->oom_file_badness(file);
+
+ return 0;
+}
+
+
+/**
* oom_badness - heuristic function to determine which candidate task to kill
* @p: task struct of which task we should calculate
* @totalpages: total present RAM allowed for page allocation
@@ -222,6 +239,12 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg,
*/
points = get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS) +
mm_pgtables_bytes(p->mm) / PAGE_SIZE;
+
+ /*
+ * Add how much memory a task uses in opened files, e.g. device drivers.
+ */
+ iterate_fd(p->files, 0, oom_file_badness, &points);
+
task_unlock(p);

/*
--
2.7.4