[PATCH 5/9] oom: make oom_unkillable_task() helper function

KOSAKI Motohiro
2010-06-16T11:33:23Z

Now, we have the same task check in three places. Unify it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
---
mm/oom_kill.c | 39 +++++++++++++++++++++++----------------
1 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 3e48023..12204c7 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -276,6 +276,26 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
}
#endif

+/* return true if the task is not adequate as candidate victim task. */
+static bool oom_unkillable_task(struct task_struct *p, struct mem_cgroup *mem,
+ const nodemask_t *nodemask)
+{
+ if (is_global_init(p))
+ return true;
+ if (p->flags & PF_KTHREAD)
+ return true;
+
+ /* When mem_cgroup_out_of_memory() and p is not member of the group */
+ if (mem && !task_in_mem_cgroup(p, mem))
+ return true;
+
+ /* p may not have freeable memory in nodemask */
+ if (!has_intersects_mems_allowed(p, nodemask))
+ return true;
+
+ return false;
+}
+
/*
* Simple selection loop. We chose the process with the highest
* number of 'points'. We expect the caller will lock the tasklist.
@@ -294,12 +314,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
for_each_process(p) {
unsigned long points;

- /* skip the init task and kthreads */
- if (is_global_init(p) || (p->flags & PF_KTHREAD))
- continue;
- if (mem && !task_in_mem_cgroup(p, mem))
- continue;
- if (!has_intersects_mems_allowed(p, nodemask))
+ if (oom_unkillable_task(p, mem, nodemask))
continue;

/*
@@ -440,11 +455,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
* When oom_kill_allocating_task is enabled, p can be
* unkillable. check it first.
*/
- if (is_global_init(p) || (p->flags & PF_KTHREAD))
- return 1;
- if (mem && !task_in_mem_cgroup(p, mem))
- return 1;
- if (!has_intersects_mems_allowed(p, nodemask))
+ if (oom_unkillable_task(p, mem, nodemask))
return 1;

if (printk_ratelimit())
@@ -477,11 +488,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,

if (child->mm == p->mm)
continue;
- if (child->flags & PF_KTHREAD)
- continue;
- if (mem && !task_in_mem_cgroup(child, mem))
- continue;
- if (!has_intersects_mems_allowed(child, nodemask))
+ if (oom_unkillable_task(child, mem, nodemask))
continue;

/* oom_badness() returns 0 if the thread is unkillable */
--
1.6.5.2