Re: [PATCH] oom_reaper: switch to struct list_head for reap queue

From	Aleksa Sarai <asarai@suse.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH] oom_reaper: switch to struct list_head for reap queue
Date	2017-02-14 18:00 +0100
Message-ID	<taOCl-4hz-1@gated-at.bofh.it> (permalink)
References	<taMTU-3rm-3@gated-at.bofh.it> <taOj0-4aW-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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>> Rather than implementing an open addressing linked list structure
>> ourselves, use the standard list_head structure to improve consistency
>> with the rest of the kernel and reduce confusion.
>>
>> Cc: Michal Hocko <mhocko@suse.com>
>> Cc: Oleg Nesterov <oleg@redhat.com>
>> Signed-off-by: Aleksa Sarai <asarai@suse.de>
>> ---
>>  include/linux/sched.h |  6 +++++-
>>  kernel/fork.c         |  4 ++++
>>  mm/oom_kill.c         | 24 +++++++++++++-----------
>>  3 files changed, 22 insertions(+), 12 deletions(-)
>>
>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>> index e93594b88130..d8bcd0f8c5fe 100644
>> --- a/include/linux/sched.h
>> +++ b/include/linux/sched.h
>> @@ -1960,7 +1960,11 @@ struct task_struct {
>>  #endif
>>  	int pagefault_disabled;
>>  #ifdef CONFIG_MMU
>> -	struct task_struct *oom_reaper_list;
>> +	/*
>> +	 * List of threads that have to be reaped by OOM (rooted at
>> +	 * &oom_reaper_list in mm/oom_kill.c).
>> +	 */
>> +	struct list_head oom_reaper_list;
>
> This is an extra pointer to task_struct and more lines of code to
> accomplish the same thing. Why would we want to do that?

I don't think it's more "actual" lines of code (I think the wrapping is 
inflating the line number count), but switching it means that it's more 
in line with other queues in the kernel (it took me a bit to figure out 
what was going on with oom_reaper_list beforehand).

-- 
Aleksa Sarai
Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/

Thread

[PATCH] oom_reaper: switch to struct list_head for reap queue Aleksa Sarai <asarai@suse.de> - 2017-02-14 16:10 +0100
  Re: [PATCH] oom_reaper: switch to struct list_head for reap queue Johannes Weiner <hannes@cmpxchg.org> - 2017-02-14 17:40 +0100
    Re: [PATCH] oom_reaper: switch to struct list_head for reap queue Aleksa Sarai <asarai@suse.de> - 2017-02-14 18:00 +0100
      Re: [PATCH] oom_reaper: switch to struct list_head for reap queue Oleg Nesterov <oleg@redhat.com> - 2017-02-14 18:40 +0100
        Re: [PATCH] oom_reaper: switch to struct list_head for reap queue Aleksa Sarai <asarai@suse.de> - 2017-02-15 10:10 +0100
          Re: [PATCH] oom_reaper: switch to struct list_head for reap queue Michal Hocko <mhocko@kernel.org> - 2017-02-20 17:00 +0100
      Re: [PATCH] oom_reaper: switch to struct list_head for reap queue Ingo Molnar <mingo@kernel.org> - 2017-02-15 09:10 +0100

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