Re: [PATCH 1/2] alpha: use .data.init_task instead of .data.init_thread.

On Fri, 31 Jul 2009, Richard Henderson wrote:

> On 07/31/2009 02:23 PM, Richard Henderson wrote:
> > Similarly it is *not* a bug that the page_aligned sections were before
> > data, because we already knew we had 2 page alignment from the end of
> > init + 2 pages of init_thread.
> 
> Indeed, I'll go further and say that the common definition of RW_DATA_SECTION
> is buggy.
[...]
> Given that we align the entire .data section why have interior padding to
> re-align for page-aligned data?  Surely a better ordering would be
[...]

Agreed.  I actually commented on this issue in one of the drafts of 
RW_DATA_SECTION, but forgot to check again whether Sam had addressed it 
when reviewing the final version.  Fortunately we're talking about a small 
inefficiency, not something more serious.  Below is your proposed change 
in patch form; I hope Sam will take a look at it.

	-Tim Abbott

Optimize the ordering of sections in RW_DATA_SECTION.

The current RW_DATA_SECTION macro doesn't place the various 
PAGE_SIZE-aligned sections next to each other.  This could result in up to 
a page of memory being wasted realigning to PAGE_SIZE twice.

Signed-off-by: Tim Abbott <tabbott <at> ksplice.com>
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