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Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures

From Tejun Heo <tj@kernel.org>
Newsgroups linux.kernel
Subject Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures
Date 2016-04-08 19:50 +0200
Message-ID <rlIHD-7v9-1@gated-at.bofh.it> (permalink)
References <rlHiy-6xv-5@gated-at.bofh.it> <rlHiy-6xv-21@gated-at.bofh.it> <rlHLA-6M8-11@gated-at.bofh.it> <rlIxY-7r6-39@gated-at.bofh.it>
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Hello,

On Fri, Apr 08, 2016 at 01:32:52PM -0400, Waiman Long wrote:
> Yes, I think it will be more efficient to use percpu_counter in this case.
> The preempt_disable/enable() calls are pretty cheap. Once in a while, you
> need to take the lock and update the global count. How about I change the
> 2nd patch to use percpu_counter internally when 64-bit counts are needed in
> 32-bit archs, but use the regular percpu counts on 64-bit archs? If you are
> OK with that, I can update the patch accordingly.

Does having percpu_stats as a separate construct make sense after
that?  Just use percpu_counter directly?  You end up wasting a bit
more space that way but most of space overhead for these things are in
percpu part anyway, so in proportion it shouldn't make that much of a
difference.

Thanks.

-- 
tejun

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Thread

[PATCH v2 0/4] ext4: Improve parallel I/O performance on NVDIMM Waiman Long <Waiman.Long@hpe.com> - 2016-04-08 18:20 +0200
  [PATCH v2 3/4] ext4: Pass in DIO_SKIP_DIO_COUNT flag if inode_dio_begin() called Waiman Long <Waiman.Long@hpe.com> - 2016-04-08 18:20 +0200
  [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures Waiman Long <Waiman.Long@hpe.com> - 2016-04-08 18:20 +0200
    Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit  architectures Tejun Heo <tj@kernel.org> - 2016-04-08 18:50 +0200
      Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures Waiman Long <waiman.long@hpe.com> - 2016-04-08 19:40 +0200
        Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit  architectures Tejun Heo <tj@kernel.org> - 2016-04-08 19:50 +0200
          Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures Waiman Long <waiman.long@hpe.com> - 2016-04-08 20:50 +0200
            Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit  architectures Tejun Heo <tj@kernel.org> - 2016-04-12 00:20 +0200
              Re: [PATCH v2 2/4] percpu_stats: Enable 64-bit counts in 32-bit architectures Waiman Long <waiman.long@hpe.com> - 2016-04-12 20:20 +0200
  [PATCH v2 1/4] percpu_stats: Simple per-cpu statistics count helper functions Waiman Long <Waiman.Long@hpe.com> - 2016-04-08 18:20 +0200
    Re: [PATCH v2 1/4] percpu_stats: Simple per-cpu statistics count  helper functions kbuild test robot <lkp@intel.com> - 2016-04-08 18:50 +0200
    Re: [PATCH v2 1/4] percpu_stats: Simple per-cpu statistics count  helper functions kbuild test robot <lkp@intel.com> - 2016-04-08 19:50 +0200

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