From: Aaron Tomlin <atomlin@redhat.com>
To: David Rientjes <rientjes@google.com>
Cc: linux-mm@kvack.org, akpm@linux-foundation.org, vbabka@suse.cz,
mhocko@suse.com, penguin-kernel@i-love.sakura.ne.jp,
llong@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm/oom_kill: show oom eligibility when displaying the current memory state of all tasks
Date: Tue, 15 Jun 2021 13:02:57 +0100 [thread overview]
Message-ID: <20210615120257.zkumnojewtrqnx5k@ava.usersys.com> (raw)
In-Reply-To: <6fc8beef-4dbb-b49a-4653-90fe564941a6@google.com>
On Sun 2021-06-13 16:47 -0700, David Rientjes wrote:
> On Sat, 12 Jun 2021, Aaron Tomlin wrote:
>
> > diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> > index eefd3f5fde46..094b7b61d66f 100644
> > --- a/mm/oom_kill.c
> > +++ b/mm/oom_kill.c
> > @@ -160,6 +160,27 @@ static inline bool is_sysrq_oom(struct oom_control *oc)
> > return oc->order == -1;
> > }
> >
> > +/**
> > + * is_task_eligible_oom - determine if and why a task cannot be OOM killed
> > + * @tsk: task to check
> > + *
> > + * Needs to be called with task_lock().
> > + */
> > +static const char * is_task_oom_eligible(struct task_struct *p)
>
> You should be able to just return a char.
I see, sure.
> > +{
> > + long adj;
> > +
> > + adj = (long)p->signal->oom_score_adj;
> > + if (adj == OOM_SCORE_ADJ_MIN)
> > + return "S";
>
> The value is already printed in the task dump, this doesn't look to add
> any information.
I understand and perhaps it does not make sense; albeit, the reader might
not understand the meaning of OOM_SCORE_ADJ_MIN.
> > + else if (test_bit(MMF_OOM_SKIP, &p->mm->flags)
> > + return "R";
>
> We should be doing the task dump only when we're killing a victim (unless
> we're panicking), so something else has been chosen. Since we would have
> oom killed a process with MMF_OOM_SKIP already, can we simply choose to
> not print a line for this process?
I'd prefer not to show such tasks, when displaying potential OOM victims
(including those in_vfork()) as in my opinion, it can be misleading to the
reader. That said, a case has been made to maintain their inclusion.
However, should in_vfork() even be shown in the actual report?
>
> > @@ -401,12 +422,13 @@ static int dump_task(struct task_struct *p, void *arg)
> > return 0;
> > }
> >
> > - pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %s\n",
> > + pr_info("[%7d] %5d %5d %8lu %8lu %8ld %8lu %5hd %13s %s\n",
>
> 13 characters for one char output?
This was to maintain some alignment but fair enough.
> > static void dump_tasks(struct oom_control *oc)
> > {
> > pr_info("Tasks state (memory values in pages):\n");
> > - pr_info("[ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name\n");
> > + pr_info("[ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj oom eligible? name\n");
>
> Field names are single words.
Understood.
Kind regards,
--
Aaron Tomlin
next prev parent reply other threads:[~2021-06-15 12:03 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-12 20:46 [PATCH v2] mm/oom_kill: show oom eligibility when displaying the current memory state of all tasks Aaron Tomlin
2021-06-13 23:47 ` David Rientjes
2021-06-13 23:47 ` David Rientjes
2021-06-15 12:02 ` Aaron Tomlin [this message]
2021-06-14 6:44 ` Michal Hocko
2021-06-15 11:51 ` Aaron Tomlin
2021-06-15 12:42 ` Michal Hocko
2021-06-16 20:18 ` Aaron Tomlin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210615120257.zkumnojewtrqnx5k@ava.usersys.com \
--to=atomlin@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=llong@redhat.com \
--cc=mhocko@suse.com \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=rientjes@google.com \
--cc=vbabka@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.