Is my custom field added in page struct guaranteed zero when a page is allocated ?

[Pranay Srivastava]

On Mar 14, 2014 9:26 PM, "朱" <zly.king at 163.com> wrote:
>
> hi,
> I add a u64 field in struct page to record corresponding disk sector
postion. I will change and read this field when dealing with page cache
staff.

As you already have modified page struct, how about modifying prep_new_page
as well. Put a zero in that field after the page refcount is set.

I think that way it'll remain.hidden instead of your specific code zeroing
it everytime you need it.

> I want it stays zero unless my code change its value. Will the kernel 's
allocating code guarantee that
> the field is zero when the page is allocated? or Need I add some code to
the allocating routine to explicitly fill the field with zero?
>
> Regard，
> Lingyu Zhu
>
>
>
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