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Re: [PATCH 0/4] block: account io: kill atomic operations

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On Thu, Jul 16, 2015 at 08:48:41AM -0600, Jens Axboe wrote:
> I've played with this before, but always ran into the hurdle of making
> part_in_flight() too expensive ended up hurting results in the end. Making
> the inc/dec parts of accounting percpu is a no-brainer, unfortunately the
> summing then becomes pretty expensive. I'll run this through some testing
> and see what kind of results I get.

The only place which could be a problem is part_round_stats() and we
can do that *way* lazier.  I don't think we're using that internally.
Why are we even invoking it from IO issue / completion path?

Thanks.

-- 
tejun
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[PATCH 0/4] block: account io: kill atomic operations Ming Lei <tom.leiming@gmail.com> - 2015-07-16 05:20 +0200
  [PATCH 3/4] block: partition: introduce 'cpu' para to part_inc|dec_in_flight Ming Lei <tom.leiming@gmail.com> - 2015-07-16 05:30 +0200
  [PATCH 1/4] block: partition: introduce hd_free_part() Ming Lei <tom.leiming@gmail.com> - 2015-07-16 05:30 +0200
  [PATCH 2/4] block: partition: convert percpu ref Ming Lei <tom.leiming@gmail.com> - 2015-07-16 05:30 +0200
    Re: [PATCH 2/4] block: partition: convert percpu ref Tejun Heo <tj@kernel.org> - 2015-07-16 16:40 +0200
  [PATCH 4/4] block: account io: convert part->in_fligh[] into percpu variable Ming Lei <tom.leiming@gmail.com> - 2015-07-16 05:30 +0200
    Re: [PATCH 4/4] block: account io: convert part->in_fligh[] into  percpu variable Tejun Heo <tj@kernel.org> - 2015-07-16 16:50 +0200
  Re: [PATCH 0/4] block: account io: kill atomic operations Jens Axboe <axboe@kernel.dk> - 2015-07-16 16:50 +0200
    Re: [PATCH 0/4] block: account io: kill atomic operations Tejun Heo <tj@kernel.org> - 2015-07-16 17:00 +0200
      Re: [PATCH 0/4] block: account io: kill atomic operations Jens Axboe <axboe@kernel.dk> - 2015-07-16 17:10 +0200
    Re: [PATCH 0/4] block: account io: kill atomic operations Jens Axboe <axboe@kernel.dk> - 2015-07-16 17:10 +0200
    Re: [PATCH 0/4] block: account io: kill atomic operations Ming Lei <tom.leiming@gmail.com> - 2015-07-16 17:10 +0200

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