回复： what's zero_pages for in paging_int

Hi, Rusel:)

      I'm a newbie in this mailing list as well as on my kernel adventure,thanks for your kind advice and crystal explanation about zero-pages.

Best regards
--rocky

quoted

Please don't post extracts of code which are part of mainline kernels.
Just provide a reference to where they are.  Most people who will reply
to you already have a copy of the kernel source.

 

 
------------------ ???? ------------------
???: "Russell King - ARM Linux"[off-list ref];
????: 2009?10?30?(???) ??6:31
???: "???"[off-list ref]; 
??: "linux-arm-kernel"[off-list ref]; 
??: Re: what's zero_pages for in paging_int

 
On Fri, Oct 30, 2009 at 11:18:13AM +0800, ??? wrote:

     In paging_int, after setting up bootmem allocator, why zero page
is needed? i cannot see any things usefull resides on that page,
something i missing obviously?

Please don't post extracts of code which are part of mainline kernels.
Just provide a reference to where they are.  Most people who will reply
to you already have a copy of the kernel source.

The zero page is a page full of zeros, and is used to provide userspace
with a write-protected initial BSS segment.  When userspace first writes
to the BSS segments, a page fault happens, and a replacement writable
zero page will be given to the program.

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