On 06/03, KOSAKI Motohiro wrote:
>
> dump_task() should use find_lock_task_mm() too. It is necessary for
> protecting task-exiting race.
This patch also replaces the pointless do_each_thread() with
for_each_process(), good.
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> ---
> mm/oom_kill.c | 37 ++++++++++++++++++++-----------------
> 1 files changed, 20 insertions(+), 17 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 35a2ecc..6360c56 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -345,35 +345,38 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
> */
> static void dump_tasks(const struct mem_cgroup *mem)
> {
> - struct task_struct *g, *p;
> + struct task_struct *p;
> + struct task_struct *task;
>
> printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj "
> "name\n");
> - do_each_thread(g, p) {
> - struct mm_struct *mm;
>
> - if (mem && !task_in_mem_cgroup(p, mem))
> + for_each_process(p) {
> + /*
> + * We don't have is_global_init() check here, because the old
> + * code do that. printing init process is not big matter. But
> + * we don't hope to make unnecessary compatiblity breaking.
> + */
> + if (p->flags & PF_KTHREAD)
> continue;
> - if (!thread_group_leader(p))
> + if (mem && !task_in_mem_cgroup(p, mem))
> continue;
>
> - task_lock(p);
> - mm = p->mm;
> - if (!mm) {
> + task = find_lock_task_mm(p);
> + if (!task)
> /*
> - * total_vm and rss sizes do not exist for tasks with no
> - * mm so there's no need to report them; they can't be
> - * oom killed anyway.
> + * Probably oom vs task-exiting race was happen and ->mm
> + * have been detached. thus there's no need to report them;
> + * they can't be oom killed anyway.
> */
> - task_unlock(p);
> continue;
> - }
> +
> printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n",
> - p->pid, __task_cred(p)->uid, p->tgid, mm->total_vm,
> - get_mm_rss(mm), (int)task_cpu(p), p->signal->oom_adj,
> + task->pid, __task_cred(task)->uid, task->tgid, task->mm->total_vm,
> + get_mm_rss(task->mm), (int)task_cpu(task), task->signal->oom_adj,
> p->comm);
> - task_unlock(p);
> - } while_each_thread(g, p);
> + task_unlock(task);
> + }
> }
>
> static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
> --
> 1.6.5.2
>
>
>
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