Messages in this thread | | | Date | Fri, 18 May 2007 11:14:26 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [rfc] increase struct page size?! |
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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?
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