lkml.org 
[lkml]   [2007]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [rfc] increase struct page size?!
On Fri, 18 May 2007, Nick Piggin wrote:

> However we don't have to let those 8 bytes go to waste: we can use them
> to store the virtual address of the page, which kind of makes sense for
> 64-bit, because they can likely to use complicated memory models.

That is not a valid consideration anymore. There is virtual memmap update
pending with the sparsemem folks that will simplify things.

> Many batch operations on struct page are completely random, and as such, I
> think it is better if each struct page fits completely into a single
> cacheline even if it means being slightly larger.

Right. That would simplify the calculations.

> Don't let this space go to waste though, we can use page->virtual in order
> to optimise page_address operations.

page->virtual is a benefit if the page is cache hot. Otherwise it may
cause a useless lookup.

I wonder if there are other uses for the free space?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-05-18 20:19    [from the cache]
©2003-2011 Jasper Spaans