On Tue, Mar 28, 2006 at 11:16:19AM -0800, Dave Hansen wrote:
> Could you explain a bit how this works on ia64? I know about the
> vmem_map. Is the time spent on filling TLB entries when you hit a
> 'struct page' that isn't backed by real memory?
Time is wasted trying to fill the TLB entry for the vmem_map. When it
fails, we show_mem() advances to the next page which repeats the sequence.
Jack had thrown out a couple suggestions. One was essentially what
you proposed below. The other was advance i to point the next page
of pfns. He frowned when saying the second, but I don't recall exactly
why he frowned.
> Maybe something like this in your show_mem():
>
> for_each_pgdat(pgdat) {
> ...
> for(i = 0; i < pgdat->node_spanned_pages; i++) {
> struct page *page;
> if (pfn_valid(pgdat->node_start_pfn + i))
> page = pfn_to_page(pgdat->node_start_pfn + i);
> else
> - continue;
> + /* -1 to offset i++ */
> + pfn += hole_nr_pages(pfn) - 1;
>
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