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* [PATCH 0/3] percpu: Optimize percpu accesses
@ 2008-01-23  4:49 travis
  2008-01-23  4:49 ` [PATCH 1/3] generic: Percpu infrastructure to rebase the per cpu area to zero travis
                   ` (3 more replies)
  0 siblings, 4 replies; 12+ messages in thread
From: travis @ 2008-01-23  4:49 UTC (permalink / raw)
  To: Andrew Morton, Andi Kleen, mingo
  Cc: Christoph Lameter, jeremy, linux-mm, linux-kernel

This patchset provides the following:

  * Generic: Percpu infrastructure to rebase the per cpu area to zero

    This provides for the capability of accessing the percpu variables
    using a local register instead of having to go through a table
    on node 0 to find the cpu-specific offsets.  It also would allow
    atomic operations on percpu variables to reduce required locking.

  * x86_64: Fold pda into per cpu area

    Declare the pda as a per cpu variable. This will move the pda
    area to an address accessible by the x86_64 per cpu macros.
    Subtraction of __per_cpu_start will make the offset based from
    the beginning of the per cpu area.  Since %gs is pointing to the
    pda, it will then also point to the per cpu variables and can be
    accessed thusly:

	%gs:[&per_cpu_xxxx - __per_cpu_start]

  * x86_64: Rebase per cpu variables to zero

    Take advantage of the zero-based per cpu area provided above.
    Then we can directly use the x86_32 percpu operations. x86_32
    offsets %fs by __per_cpu_start. x86_64 has %gs pointing directly
    to the pda and the per cpu area thereby allowing access to the
    pda with the x86_64 pda operations and access to the per cpu
    variables using x86_32 percpu operations.

Based on 2.6.24-rc8-mm1

Signed-off-by: Mike Travis <travis@sgi.com>
Reviewed-by: Christoph Lameter <clameter@sgi.com>
---

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^ permalink raw reply	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2008-01-29 20:13 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-01-23  4:49 [PATCH 0/3] percpu: Optimize percpu accesses travis
2008-01-23  4:49 ` [PATCH 1/3] generic: Percpu infrastructure to rebase the per cpu area to zero travis
2008-01-23  4:49 ` [PATCH 2/3] x86_64: Fold pda into per cpu area travis
2008-01-23  4:49 ` [PATCH 3/3] x86_64: Rebase per cpu variables to zero travis
2008-01-24 22:46 ` [PATCH 0/3] percpu: Optimize percpu accesses Ingo Molnar
2008-01-25  0:17   ` Mike Travis
2008-01-25  0:25     ` Ingo Molnar
2008-01-25  0:58       ` Mike Travis
2008-01-25  1:18         ` Jeremy Fitzhardinge
2008-01-25  1:46         ` Jeremy Fitzhardinge
2008-01-29 20:00   ` Mike Travis
2008-01-29 20:13     ` Christoph Lameter

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