Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee"

From	Linus Torvalds <torvalds@linux-foundation.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee"
Date	2015-09-08 19:40 +0200
Message-ID	<q6v2b-2Em-19@gated-at.bofh.it> (permalink)
References	<q6uIN-2hN-7@gated-at.bofh.it> <q6uIN-2hN-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Tue, Sep 8, 2015 at 10:14 AM, Oleg Nesterov <oleg@redhat.com> wrote:
>
> Now that fput() can't abuse ->task_works list, we can restore the FIFO
> ordering. Yes, currently there are no in-kernel users which need this,
> but I think task_work_add() will have more users and FIFO makes more
> sense if (unlike fput/mntput) the callbacks change the task's state.

So quite frankly, regardless of the other patches, I'd almost rather
see the workqueue not being ordered. I don't think anybody pointed at
any code that could possibly care. And if nobody cares, why add the
code and the CPU cycles to do this?

The other patches I do like - why add those list operations that are
just guaranteed to mess up the cache to add the file descriptors to
the workqueue list, when we can just do the operation directly? So I
think that's a separate issue.

               Linus
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Thread

[PATCH 3/3] Revert "task_work: remove fifo ordering guarantee" Oleg Nesterov <oleg@redhat.com> - 2015-09-08 19:20 +0200
  Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee" Linus Torvalds <torvalds@linux-foundation.org> - 2015-09-08 19:40 +0200
    Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee" Linus Torvalds <torvalds@linux-foundation.org> - 2015-09-08 19:50 +0200
    Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee" Oleg Nesterov <oleg@redhat.com> - 2015-09-09 15:20 +0200
      Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee" Linus Torvalds <torvalds@linux-foundation.org> - 2015-09-09 18:20 +0200
        Re: [PATCH 3/3] Revert "task_work: remove fifo ordering guarantee" Oleg Nesterov <oleg@redhat.com> - 2015-09-09 18:50 +0200

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