oom: oom_kill_process: fix the child_points logic

oom_kill_process() starts with victim_points == 0.  This means that
(most likely) any child has more points and can be killed erroneously.

Also, "children has a different mm" doesn't match the reality, we should
check child->mm != t->mm.  This check is not exactly correct if t->mm ==
NULL but this doesn't really matter, oom_kill_task() will kill them
anyway.

Note: "Kill all processes sharing p->mm" in oom_kill_task() is wrong
too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2011-03-14 20:05:30 +01:00 committed by Linus Torvalds
parent 5f40d42094
commit dc1b83ab08

View file

@ -458,10 +458,10 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
struct mem_cgroup *mem, nodemask_t *nodemask,
const char *message)
{
struct task_struct *victim = p;
struct task_struct *victim;
struct task_struct *child;
struct task_struct *t = p;
unsigned int victim_points = 0;
struct task_struct *t;
unsigned int victim_points;
if (printk_ratelimit())
dump_header(p, gfp_mask, order, mem, nodemask);
@ -487,10 +487,15 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
* parent. This attempts to lose the minimal amount of work done while
* still freeing memory.
*/
victim_points = oom_badness(p, mem, nodemask, totalpages);
victim = p;
t = p;
do {
list_for_each_entry(child, &t->children, sibling) {
unsigned int child_points;
if (child->mm == t->mm)
continue;
/*
* oom_badness() returns 0 if the thread is unkillable
*/