find_lock_task_mm() should be documented so that we clearly understand
what it does and why we need it.
At the same time, remove a stale coment about dereferencing of a local
variable "mm" in badness() which no longer exists and was removed when
find_lock_task_mm() was added.
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
mm/oom_kill.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -81,6 +81,12 @@ static bool has_intersects_mems_allowed(struct task_struct *tsk,
}
#endif /* CONFIG_NUMA */
+/*
+ * The process p may have detached its own ->mm while exiting or through
+ * use_mm(), but one or more of its subthreads may still have a valid
+ * pointer. Return p, or any of its subthreads with a valid ->mm, with
+ * task_lock() held.
+ */
static struct task_struct *find_lock_task_mm(struct task_struct *p)
{
struct task_struct *t = p;
@@ -135,10 +141,6 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
* The memory size of the process is the basis for the badness.
*/
points = p->mm->total_vm;
-
- /*
- * After this unlock we can no longer dereference local variable `mm'
- */
task_unlock(p);
/*
--
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