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Groups > linux.kernel > #1281356 > unrolled thread
| Started by | Andrew Morton <akpm@linux-foundation.org> |
|---|---|
| First post | 2015-12-02 00:50 +0100 |
| Last post | 2015-12-02 09:20 +0100 |
| Articles | 3 — 3 participants |
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Re: [PATCH] oom_kill: add option to disable dump_stack() Andrew Morton <akpm@linux-foundation.org> - 2015-12-02 00:50 +0100
Re: [PATCH] oom_kill: add option to disable dump_stack() David Rientjes <rientjes@google.com> - 2015-12-02 01:10 +0100
Re: [PATCH] oom_kill: add option to disable dump_stack() Michal Hocko <mhocko@kernel.org> - 2015-12-02 09:20 +0100
| From | Andrew Morton <akpm@linux-foundation.org> |
|---|---|
| Date | 2015-12-02 00:50 +0100 |
| Subject | Re: [PATCH] oom_kill: add option to disable dump_stack() |
| Message-ID | <qB2Qi-7Sl-19@gated-at.bofh.it> |
On Fri, 23 Oct 2015 17:02:30 -0400 Aristeu Rozanski <arozansk@redhat.com> wrote:
> One of the largest chunks of log messages in a OOM is from dump_stack() and in
> some cases it isn't even necessary to figure out what's going on. In
> systems with multiple tenants/containers with limited resources each
> OOMs can be way more frequent and being able to reduce the amount of log
> output for each situation is useful.
>
> This patch adds a sysctl to allow disabling dump_stack() during an OOM while
> keeping the default to behave the same way it behaves today.
Can you get the same effect by using "dmesg -n <N>"? Probably not, I
didn't look.
> --- a/include/linux/oom.h
> +++ b/include/linux/oom.h
> @@ -115,6 +115,7 @@ static inline bool task_will_free_mem(struct task_struct *task)
>
> /* sysctls */
> extern int sysctl_oom_dump_tasks;
> +extern int sysctl_oom_dump_stack;
> extern int sysctl_oom_kill_allocating_task;
> extern int sysctl_panic_on_oom;
> #endif /* _INCLUDE_LINUX_OOM_H */
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index e69201d..c812523 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -1176,6 +1176,13 @@ static struct ctl_table vm_table[] = {
> .proc_handler = proc_dointvec,
> },
> {
> + .procname = "oom_dump_stack",
> + .data = &sysctl_oom_dump_stack,
> + .maxlen = sizeof(sysctl_oom_dump_stack),
> + .mode = 0644,
> + .proc_handler = proc_dointvec,
> + },
> + {
> .procname = "overcommit_ratio",
> .data = &sysctl_overcommit_ratio,
> .maxlen = sizeof(sysctl_overcommit_ratio),
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 1ecc0bc..bdbf83b 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -42,6 +42,7 @@
> int sysctl_panic_on_oom;
> int sysctl_oom_kill_allocating_task;
> int sysctl_oom_dump_tasks = 1;
> +int sysctl_oom_dump_stack = 1;
>
> DEFINE_MUTEX(oom_lock);
>
> @@ -384,7 +385,8 @@ static void dump_header(struct oom_control *oc, struct task_struct *p,
> current->signal->oom_score_adj);
> cpuset_print_task_mems_allowed(current);
> task_unlock(current);
> - dump_stack();
> + if (sysctl_oom_dump_stack)
> + dump_stack();
> if (memcg)
> mem_cgroup_print_oom_info(memcg, p);
> else
The patch seems reasonable to me, but it's missing the required update
to Documentation/sysctl/vm.txt.
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| From | David Rientjes <rientjes@google.com> |
|---|---|
| Date | 2015-12-02 01:10 +0100 |
| Message-ID | <qB39D-8en-9@gated-at.bofh.it> |
| In reply to | #1281356 |
On Tue, 1 Dec 2015, Andrew Morton wrote:
> > --- a/include/linux/oom.h
> > +++ b/include/linux/oom.h
> > @@ -115,6 +115,7 @@ static inline bool task_will_free_mem(struct task_struct *task)
> >
> > /* sysctls */
> > extern int sysctl_oom_dump_tasks;
> > +extern int sysctl_oom_dump_stack;
> > extern int sysctl_oom_kill_allocating_task;
> > extern int sysctl_panic_on_oom;
> > #endif /* _INCLUDE_LINUX_OOM_H */
> > diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> > index e69201d..c812523 100644
> > --- a/kernel/sysctl.c
> > +++ b/kernel/sysctl.c
> > @@ -1176,6 +1176,13 @@ static struct ctl_table vm_table[] = {
> > .proc_handler = proc_dointvec,
> > },
> > {
> > + .procname = "oom_dump_stack",
> > + .data = &sysctl_oom_dump_stack,
> > + .maxlen = sizeof(sysctl_oom_dump_stack),
> > + .mode = 0644,
> > + .proc_handler = proc_dointvec,
> > + },
> > + {
> > .procname = "overcommit_ratio",
> > .data = &sysctl_overcommit_ratio,
> > .maxlen = sizeof(sysctl_overcommit_ratio),
> > diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> > index 1ecc0bc..bdbf83b 100644
> > --- a/mm/oom_kill.c
> > +++ b/mm/oom_kill.c
> > @@ -42,6 +42,7 @@
> > int sysctl_panic_on_oom;
> > int sysctl_oom_kill_allocating_task;
> > int sysctl_oom_dump_tasks = 1;
> > +int sysctl_oom_dump_stack = 1;
> >
> > DEFINE_MUTEX(oom_lock);
> >
> > @@ -384,7 +385,8 @@ static void dump_header(struct oom_control *oc, struct task_struct *p,
> > current->signal->oom_score_adj);
> > cpuset_print_task_mems_allowed(current);
> > task_unlock(current);
> > - dump_stack();
> > + if (sysctl_oom_dump_stack)
> > + dump_stack();
> > if (memcg)
> > mem_cgroup_print_oom_info(memcg, p);
> > else
>
> The patch seems reasonable to me, but it's missing the required update
> to Documentation/sysctl/vm.txt.
>
Not sure why we'd want yet-another-sysctl for something that can trivially
filtered from the log, but owell.
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| From | Michal Hocko <mhocko@kernel.org> |
|---|---|
| Date | 2015-12-02 09:20 +0100 |
| Message-ID | <qBaNQ-4B0-7@gated-at.bofh.it> |
| In reply to | #1281356 |
On Tue 01-12-15 15:43:53, Andrew Morton wrote: [...] > > diff --git a/mm/oom_kill.c b/mm/oom_kill.c > > index 1ecc0bc..bdbf83b 100644 > > --- a/mm/oom_kill.c > > +++ b/mm/oom_kill.c > > @@ -42,6 +42,7 @@ > > int sysctl_panic_on_oom; > > int sysctl_oom_kill_allocating_task; > > int sysctl_oom_dump_tasks = 1; > > +int sysctl_oom_dump_stack = 1; > > > > DEFINE_MUTEX(oom_lock); > > > > @@ -384,7 +385,8 @@ static void dump_header(struct oom_control *oc, struct task_struct *p, > > current->signal->oom_score_adj); > > cpuset_print_task_mems_allowed(current); > > task_unlock(current); > > - dump_stack(); > > + if (sysctl_oom_dump_stack) > > + dump_stack(); > > if (memcg) > > mem_cgroup_print_oom_info(memcg, p); > > else > > The patch seems reasonable to me, but it's missing the required update > to Documentation/sysctl/vm.txt. I thought we have agreed to go via KERN_DEBUG log level for the backtrace. Aristeu has posted a patch for that already. -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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