some questions about kernel source

[loody]

hi :


2011/2/18 John Mahoney <jmahoney at waav.com>:
> On Thu, Feb 17, 2011 at 9:17 AM, loody <miloody at gmail.com> wrote:
>> hi :-)
>>
>> 2011/2/16 Mulyadi Santosa <mulyadi.santosa at gmail.com>:
>>> Hi :)
>>>
>>> On Wed, Feb 16, 2011 at 12:59, Rajat Jain <rajatjain at juniper.net> wrote:
>>>> Hello loody,
>>>>
>>>>> 1. in kernel/trace, I always see "__read_mostly" at the end of
>>>>> parameter is that a compiler optimization parameter?
>>>>
>>>> Yes, it is a hint to the compiler that the parameter is mostly read, thus if the compiler has to make a decision between optimizing one of the read / write paths, it will optimize the read path even at the expense of write path.
>>>
>>>
>>> To be precise, they will be grouped into same cache line as much as
>>> possible. By doing so, those cache line won't be invalidated so often
>>> (keeping them "hot" :) hehehhe )
>>
>> I cannot find it on the gcc manual.
>> is it a option in kernel for kernel usage?
>> if so, where I can found them.
>> If not, can I use it on normal user level program?
>>
>
> It is a macro defined for x86 as:
>
> #define __read_mostly __attribute__((__section__(".data..read_mostly")))
>
> http://lxr.linux.no/linux+v2.6.37/arch/x86/include/asm/cache.h
I found where you pointed out but I try to find out where is it in the
mips arch.
thank you,
miloody