On Fri 20-05-16 20:51:56, Tetsuo Handa wrote:
[...]
> +static bool has_pending_victim(struct task_struct *p)
> +{
> + struct task_struct *t;
> + bool ret = false;
> +
> + rcu_read_lock();
> + for_each_thread(p, t) {
> + if (test_tsk_thread_flag(t, TIF_MEMDIE)) {
> + ret = true;
> + break;
> + }
> + }
> + rcu_read_unlock();
> + return ret;
> +}
And so you do not speed up anything in the end because you have to
iterate all threads anyway yet you add quite some code on top. No I do
not like it. This is no longer a cleanup...
[...]
> Note that "[PATCH v3] mm,oom: speed up select_bad_process() loop." temporarily
> broke oom_task_origin(task) case, for oom_select_bad_process() might select
> a task without mm because oom_badness() which checks for mm != NULL will not be
> called.
How can we have oom_task_origin without mm? The flag is set explicitly
while doing swapoff resp. writing to ksm. We clear the flag before
exiting.
[...]
> By the way, I noticed that mem_cgroup_out_of_memory() might have a bug about its
> return value. It returns true if hit OOM_SCAN_ABORT after chosen != NULL, false
> if hit OOM_SCAN_ABORT before chosen != NULL. Which is expected return value?
true. Care to send a patch?
--
Michal Hocko
SUSE Labs
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