Re: [PATCH] mm/oom: added option 'oom_dump_task_cmdline'

[Randy Dunlap <rdunlap@infradead.org>]

On 2/19/19 8:30 PM, Bujnak, Stepan wrote:
> On Wed, Feb 20, 2019 at 5:10 AM Randy Dunlap <rdunlap@infradead.org> wrote:
>>
>> Hi,
>>
>> Spell it out correctly (2 places):
> This is not a typo. It actually refers to the oom_dump_tasks option,
> in a sense that when that option is enabled,
> this option (oom_dump_task_cmdline) additionally displays task
> cmdline instead of task name.
>>

OK, thanks for clarifying.

>>
>> On 2/19/19 7:22 PM, Stepan Bujnak wrote:
>>> When oom_dump_tasks is enabled, this option will try to display task
>>
>>   When oom_dump_task_cmdline is enabled,
>>
>>> cmdline instead of the command name in the system-wide task dump.
>>>
>>> This is useful in some cases e.g. on postgres server. If OOM killer is
>>> invoked it will show a bunch of tasks called 'postgres'. With this
>>> option enabled it will show additional information like the database
>>> user, database name and what it is currently doing.
>>>
>>> Other example is python. Instead of just 'python' it will also show the
>>> script name currently being executed.
>>>
>>> Signed-off-by: Stepan Bujnak <stepan@pex.com>
>>> ---
>>>  Documentation/sysctl/vm.txt | 10 ++++++++++
>>>  include/linux/oom.h         |  1 +
>>>  kernel/sysctl.c             |  7 +++++++
>>>  mm/oom_kill.c               | 20 ++++++++++++++++++--
>>>  4 files changed, 36 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
>>> index 187ce4f599a2..74278c8c30d2 100644
>>> --- a/Documentation/sysctl/vm.txt
>>> +++ b/Documentation/sysctl/vm.txt
>>> @@ -50,6 +50,7 @@ Currently, these files are in /proc/sys/vm:
>>>  - nr_trim_pages         (only if CONFIG_MMU=n)
>>>  - numa_zonelist_order
>>>  - oom_dump_tasks
>>> +- oom_dump_task_cmdline
>>>  - oom_kill_allocating_task
>>>  - overcommit_kbytes
>>>  - overcommit_memory
>>> @@ -639,6 +640,15 @@ The default value is 1 (enabled).
>>>
>>>  ==============================================================
>>>
>>> +oom_dump_task_cmdline
>>> +
>>> +When oom_dump_tasks is enabled, this option will try to display task cmdline
>>
>>    When oom_dump_task_cmdline is enabled,
>>
>>> +instead of the command name in the system-wide task dump.
>>> +
>>> +The default value is 0 (disabled).
>>> +
>>> +==============================================================
>>> +
>>>  oom_kill_allocating_task
>>>
>>>  This enables or disables killing the OOM-triggering task in
>>> diff --git a/include/linux/oom.h b/include/linux/oom.h
>>> index d07992009265..461b15b3b695 100644
>>> --- a/include/linux/oom.h
>>> +++ b/include/linux/oom.h
>>> @@ -125,6 +125,7 @@ extern struct task_struct *find_lock_task_mm(struct task_struct *p);
>>>
>>>  /* sysctls */
>>>  extern int sysctl_oom_dump_tasks;
>>> +extern int sysctl_oom_dump_task_cmdline;
>>>  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 ba4d9e85feb8..4edc5f8e6cf9 100644
>>> --- a/kernel/sysctl.c
>>> +++ b/kernel/sysctl.c
>>> @@ -1288,6 +1288,13 @@ static struct ctl_table vm_table[] = {
>>>               .mode           = 0644,
>>>               .proc_handler   = proc_dointvec,
>>>       },
>>> +     {
>>> +             .procname       = "oom_dump_task_cmdline",
>>> +             .data           = &sysctl_oom_dump_task_cmdline,
>>> +             .maxlen         = sizeof(sysctl_oom_dump_task_cmdline),
>>> +             .mode           = 0644,
>>> +             .proc_handler   = proc_dointvec,
>>> +     },
>>>       {
>>>               .procname       = "overcommit_ratio",
>>>               .data           = &sysctl_overcommit_ratio,
>>
>>
>> thanks.
>> --
>> ~Randy


-- 
~Randy