> On Tue, 8 Jun 2010, KOSAKI Motohiro wrote:
>
> > > @@ -267,6 +259,8 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
> > > continue;
> > > if (mem && !task_in_mem_cgroup(p, mem))
> > > continue;
> > > + if (!has_intersects_mems_allowed(p))
> > > + continue;
> > >
> > > /*
> > > * This task already has access to memory reserves and is
> >
> > now we have three places of oom filtering
> > (1) select_bad_process
>
> Done.
>
> > (2) dump_tasks
>
> dump_tasks() has never filtered on this, it's possible for tasks is other
> cpusets to allocate memory on our nodes.
I have no objection because it's policy matter. but if so, dump_tasks()
should display mem_allowed mask too, probably.
otherwise, end-user can't understand why badness but not mem intersected task
didn't killed.
> > (3) oom_kill_task (when oom_kill_allocating_task==1 only)
> >
>
> Why would care about cpuset attachment in oom_kill_task()? You mean
> oom_kill_process() to filter the children list?
Ah, intersting question. OK, we have to discuss oom_kill_allocating_task
design at first.
First of All, oom_kill_process() to filter the children list and this issue
are independent and unrelated. My patch was not correct too.
Now, oom_kill_allocating_task basic logic is here. It mean, if oom_kill_process()
return 0, oom kill finished successfully. but if oom_kill_process() return 1,
fallback to normall __out_of_memory().
===================================================
static void __out_of_memory(gfp_t gfp_mask, int order, nodemask_t *nodemask)
{
struct task_struct *p;
unsigned long points;
if (sysctl_oom_kill_allocating_task)
if (!oom_kill_process(current, gfp_mask, order, 0, NULL, nodemask,
"Out of memory (oom_kill_allocating_task)"))
return;
retry:
When oom_kill_process() return 1?
I think It should be
- current is OOM_DISABLE
- current have no intersected CPUSET
- current is KTHREAD
- etc etc..
It mean, consist rule of !oom_kill_allocating_task case.
So, my previous patch didn't care to conflict "oom: sacrifice child with
highest badness score for parent" patch. Probably right way is
static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
unsigned long points, struct mem_cgroup *mem,
nodemask_t *nodemask, const char *message)
{
struct task_struct *c;
struct task_struct *t = p;
struct task_struct *victim = p;
unsigned long victim_points = 0;
struct timespec uptime;
+ /* This process is not oom killable, we need to retry to select
+ bad process */
+ if (oom_unkillable(c, mem, nodemask))
+ return 1;
if (printk_ratelimit())
dump_header(p, gfp_mask, order, mem, nodemask);
pr_err("%s: Kill process %d (%s) with score %lu or sacrifice child\n",
message, task_pid_nr(p), p->comm, points);
or something else.
What do you think?
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