Re: [patch] mm, oom: replace some information in tasklist dump

[KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>]

On Fri, Jun 22, 2012 at 5:45 PM, David Rientjes <rientjes@google.com> wrote:
> The number of ptes and swap entries are used in the oom killer's badness
> heuristic, so they should be shown in the tasklist dump.
>
> This patch adds those fields and replaces cpu and oom_adj values that are
> currently emitted.  Cpu isn't interesting and oom_adj is deprecated and
> will be removed later this year, the same information is already
> displayed as oom_score_adj which is used internally.
>
> At the same time, make the documentation a little more clear to state
> this information is helpful to determine why the oom killer chose the
> task it did to kill.
>
> Signed-off-by: David Rientjes <rientjes@google.com>
> ---
>  Documentation/sysctl/vm.txt |    7 ++++---
>  mm/oom_kill.c               |   11 ++++++-----
>  2 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
> --- a/Documentation/sysctl/vm.txt
> +++ b/Documentation/sysctl/vm.txt
> @@ -502,9 +502,10 @@ oom_dump_tasks
>
>  Enables a system-wide task dump (excluding kernel threads) to be
>  produced when the kernel performs an OOM-killing and includes such
> -information as pid, uid, tgid, vm size, rss, cpu, oom_adj score, and
> -name.  This is helpful to determine why the OOM killer was invoked
> -and to identify the rogue task that caused it.
> +information as pid, uid, tgid, vm size, rss, nr_ptes, swapents,
> +oom_score_adj score, and name.  This is helpful to determine why the
> +OOM killer was invoked, to identify the rogue task that caused it,
> +and to determine why the OOM killer chose the task it did to kill.
>
>  If this is set to zero, this information is suppressed.  On very
>  large systems with thousands of tasks it may not be feasible to dump
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -371,8 +371,8 @@ static struct task_struct *select_bad_process(unsigned int *ppoints,
>  * Dumps the current memory state of all eligible tasks.  Tasks not in the same
>  * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes
>  * are not shown.
> - * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj
> - * value, oom_score_adj value, and name.
> + * State information includes task's pid, uid, tgid, vm size, rss, nr_ptes,
> + * swapents, oom_score_adj value, and name.
>  *
>  * Call with tasklist_lock read-locked.
>  */
> @@ -381,7 +381,7 @@ static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemas
>        struct task_struct *p;
>        struct task_struct *task;
>
> -       pr_info("[ pid ]   uid  tgid total_vm      rss cpu oom_adj oom_score_adj name\n");
> +       pr_info("[ pid ]   uid  tgid total_vm      rss nr_ptes swapents oom_score_adj name\n");
>        for_each_process(p) {
>                if (oom_unkillable_task(p, memcg, nodemask))
>                        continue;
> @@ -396,10 +396,11 @@ static void dump_tasks(const struct mem_cgroup *memcg, const nodemask_t *nodemas
>                        continue;
>                }
>
> -               pr_info("[%5d] %5d %5d %8lu %8lu %3u     %3d         %5d %s\n",
> +               pr_info("[%5d] %5d %5d %8lu %8lu %7lu %8lu         %5d %s\n",
>                        task->pid, from_kuid(&init_user_ns, task_uid(task)),
>                        task->tgid, task->mm->total_vm, get_mm_rss(task->mm),
> -                       task_cpu(task), task->signal->oom_adj,
> +                       task->mm->nr_ptes,

nr_ptes should be folded into rss. it's "resident".
btw, /proc rss info should be fixed too.



> +                       get_mm_counter(task->mm, MM_SWAPENTS),
>                        task->signal->oom_score_adj, task->comm);
>                task_unlock(task);
>        }
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org.  For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>