Hi Alex.
You're right. It could be simplified. It had also a bug.
The new patch is attached. please find it.
Thanks.
On Thu, Jun 01, 2006 at 01:19:02PM -0600, Alex Williamson wrote:
> Hi Isaku,
>
> I like this idea, this should really help creating dom0s with large
> memory (the swiotlb doesn't like it when we don't put any memory below
> 4GB). I'm having trouble with the loop below though, it seems overly
> complicated, but maybe I'm missing something important. We're just
> looking for gaps in the MDT above the hypercall areas, right? Could the
> original be simplified as something like this (untested):
>
> for (j = 0; j < num_mds; j++) {
> efi_memory_desc_t* next_md;
> unsigned long end;
>
> md = &efi_memmap[j];
> end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
> if (maxmem < start)
> break;
>
> // Avoid "legacy" low memory addresses and the
> // HYPERCALL patch area.
> if (md->phys_addr < HYPERCALL_END) {
> BUG_ON(end > HYPERCALL_START);
> continue;
> }
>
> if (j + 1 == num_mds && end < maxmem) {
> // End of list, map memory
> MAKE_MD(EFI_CONVENTIONAL_MEMORY, EFI_MEMORY_WB,
> end, maxmem, 0);
> continue;
> }
>
> next_md = &efi_memmap[j + 1];
>
> if (next_md->phys_addr > end) {
> // Found a gap, insert memory.
> // Should we look for some minimum sized gap?
> MAKE_MD(EFI_CONVENTIONAL_MEMORY, EFI_MEMORY_WB,
> end, min(next_md->phys_addr, maxmem), 0);
> continue;
> } else if (next_md->phys_addr < end) {
> // Bad, overlapping MDT ranges
> BUG_ON(next_md->phys_addr < end);
> }
> }
>
> The MDT we're parsing is already sorted, so there's no reason to look
> further than j + 1 for the next gap. I'm not sure I follow all of the
> tests at the end of the original loop, but I think I've captured them
> above. Does this look right? Thanks,
>
> Alex
>
> On Thu, 2006-06-01 at 11:46 +0900, Isaku Yamahata wrote:
> > +#ifdef CONFIG_XEN_IA64_DOM0_VP
> > + // simple
> > + // MAKE_MD(EFI_CONVENTIONAL_MEMORY, EFI_MEMORY_WB,
> > + // HYPERCALL_END, maxmem, 0);
> > + // is not good. Check overlap.
> > + sort(efi_memmap, i, sizeof(efi_memory_desc_t), efi_mdt_cmp,
> > NULL);
> > +
> > + num_mds = i;
> > + for (j = 0; j < num_mds; j++) {
> > + unsigned long start;
> > + unsigned long end;
> > + unsigned long next_start;
> > + int k;
> > +
> > + md = &efi_memmap[j];
> > + start = md->phys_addr;
> > + end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT);
> > +
> > + if (maxmem < start)
> > + break;
> > +
> > + // find gap
> > + next_start = maxmem;
> > + for (k = j + 1; k < num_mds; k++) {
> > + efi_memory_desc_t* next_md = &efi_memmap[k];
> > +
> > + if (end != next_md->phys_addr) {
> > + next_start = next_md->phys_addr;
> > + break;
> > + }
> > + end = next_md->phys_addr +
> > + (next_md->num_pages << EFI_PAGE_SHIFT);
> > + }
> > +
> > + if (next_start < HYPERCALL_END)
> > + continue;
> > +
> > + if (end < HYPERCALL_END)
> > + end = HYPERCALL_END;
> > + if (next_start > maxmem)
> > + next_start = maxmem;
> > + MAKE_MD(EFI_CONVENTIONAL_MEMORY, EFI_MEMORY_WB,
> > + end, next_start, 0);
> > + }
> > +#endif
> --
> Alex Williamson HP Open Source & Linux Org.
>
>
> _______________________________________________
> Xen-ia64-devel mailing list
> Xen-ia64-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-ia64-devel
>
--
yamahata
10236:8036118ac726_assign_page_to_dom0_precisely.patch
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