Ingo Molnar wrote:
> * [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote:
>
>> 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.
>
> tried it on x86.git and 1/3 did not build and 2/3 causes a boot hang
> with the attached .config.
>
> Ingo
>
The build error was fixed with the note I sent to you yesterday with a
"fixup" patch for changes in -mm but not in x86.git (attached).
I'll try out your config next.
Thanks,
Mike
Subject: x86: fixes conflict between -mm and x86.git
Ingo - you can apply this to x86.git after the other zero-based
changes to fix a build problem.
Thanks,
Mike
Signed-off-by: Mike Travis <[EMAIL PROTECTED]>
---
kernel/module.c | 3 ---
1 file changed, 3 deletions(-)
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -341,9 +341,6 @@ static inline unsigned int block_size(in
return val;
}
-/* Created by linker magic */
-extern char __per_cpu_start[], __per_cpu_end[];
-
static void *percpu_modalloc(unsigned long size, unsigned long align,
const char *name)
{
