Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup

Christoph Lameter wrote:
> On Wed, 28 Nov 2007, Jeremy Fitzhardinge wrote:
>
>   
>> I don't see the problem.  The way i386 does it inherently supports
>> per-cpu data very early on (it uses the prototype percpu section until
>> the real percpu values are set up).
>>     
>
> Ok so we could do that for x86_64 as well? There is more complicated 
> bootstrap since i386 does not support NUMA aware placement of per cpu 
> areas.
>   

Don't think it matters either way.  Before percpu is allocated, NUMA
issues don't matter.  Once they are - by whatever mechanism - you can
set the segment bases up appropriately.  The fact that you chose to put
percpu data at address X doesn't affect the percpu mechanism one way or
the other.

> percpu references are quite frequent already (vm statistics) and will be 
> more frequent after we have converted the per cpu arrays to per cpu 
> allocations.
>   

Well, I think the point is moot, because x86 will always use 32-bit
offsets.  Each reference will only be 1 byte bigger than a normal
variable reference.

    J
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• Follow-Ups:
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Christoph Lameter <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Christoph Lameter <[email protected]>

• References:
  • [patch 00/14] Per cpu code simplification
    • From: Christoph Lameter <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Rusty Russell <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Christoph Lameter <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Rusty Russell <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Jeremy Fitzhardinge <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Christoph Lameter <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Jeremy Fitzhardinge <[email protected]>
  • Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
    • From: Christoph Lameter <[email protected]>

• Prev by Date: Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
• Next by Date: RE: [PATCH 1/2] [net/wireless/iwlwifi] : iwlwifi 3945 Fix raceconditional panic.
• Previous by thread: Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
• Next by thread: Re: [patch 05/14] percpu: Use a Kconfig variable to configure arch specific percpu setup
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]