Header files and page descriptors

Is there a way I can find out the size of page descriptors in my kernel?
I am using 2.6.16.13-4

Or is it a standard size? and if it is, what size is that?

Also, another thing,

I want to find the offset of a member of a structure within the kernel header file sched.h. (/usr/include/linux)
(i.e. I want to found out how many bytes the element 'tasks' is from the start of the task_struct which is declared in sched.h)

Is there a way I can do that?

Thanks.

Originally Posted by fallen3019 Is there a way I can find out the size of page descriptors in my kernel?

By page descriptor (in linux) you probably mean the type stuct page. So the “size” of a page descriptor is “sizeof(struct page)”.