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Re: Virtually Mapped Stacks: Do not disable interrupts

From Andy Lutomirski <luto@amacapital.net>
Newsgroups linux.kernel
Subject Re: Virtually Mapped Stacks: Do not disable interrupts
Date 2017-05-19 07:40 +0200
Message-ID <tIINP-5PI-7@gated-at.bofh.it> (permalink)
References <tI9wJ-4XI-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Wed, May 17, 2017 at 8:58 AM, Christoph Lameter <cl@linux.com> wrote:
> The reason to disable interrupts seems to be to avoid switching
> to a different processor while handling per cpu data using
> individual loads and stores. If we use per cpu RMV primitives
> we will not have to disable interrupts.

I like this, except that those primitives can be quite expensive, I
think, and they're being called in a loop.  What if you first did a
this_cpu_read() to see if the value in the cache slot might be useful
before doing the heavyweight exchange?

--Andy

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Thread

Virtually Mapped Stacks: Do not disable interrupts Christoph Lameter <cl@linux.com> - 2017-05-17 18:00 +0200
  Re: Virtually Mapped Stacks: Do not disable interrupts Andy Lutomirski <luto@amacapital.net> - 2017-05-19 07:40 +0200
    Re: Virtually Mapped Stacks: Do not disable interrupts Christoph Lameter <cl@linux.com> - 2017-05-19 16:10 +0200

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