Re: [PATCH 2.6.31] ehca: Tolerate dynamic memory operations and huge pages

Michael Ellerman
2009-06-10T00:02:44Z

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On Tue, 2009-06-09 at 15:59 +0200, Hannes Hering wrote:
> This patch implements toleration of dynamic memory operations and 16 GB
> gigantic pages. On module load the driver walks through available system
> memory, checks for available memory ranges and then registers the kernel
> internal memory region accordingly. The translation of address ranges is
> implemented via a 3-level busmap.

Hi Hannes,

For those of us who haven't read the HEA spec lately, can you give us
some more detail on that? :)

How does it interact with kexec/kdump?

> +static int ehca_update_busmap(unsigned long pfn, unsigned long nr_pages)
> +{
> + unsigned long i, start_section, end_section;
> + int top, dir, idx;
> +
> + if (!nr_pages)
> + return 0;
> +
> + if (!ehca_bmap) {
> + ehca_bmap = kmalloc(sizeof(struct ehca_bmap), GFP_KERNEL);
> + if (!ehca_bmap)
> + return -ENOMEM;
> + /* Set map block to 0xFF according to EHCA_INVAL_ADDR */
> + memset(ehca_bmap, 0xFF, EHCA_TOP_MAP_SIZE);
> + }
> +
> + start_section = phys_to_abs(pfn * PAGE_SIZE) / EHCA_SECTSIZE;
> + end_section = phys_to_abs((pfn + nr_pages) * PAGE_SIZE) / EHCA_SECTSIZE;

phys_to_abs() ? As below, or does it come from somewhere else?

arch/powerpc/include/asm/abs_addr.h:
47 static inline unsigned long phys_to_abs(unsigned long pa)
48 {
49 unsigned long chunk;
50
51 /* This is a no-op on non-iSeries */
52 if (!firmware_has_feature(FW_FEATURE_ISERIES))
53 return pa;
54
55 chunk = addr_to_chunk(pa);
56
57 if (chunk < mschunks_map.num_chunks)
58 chunk = mschunks_map.mapping[chunk];
59
60 return chunk_to_addr(chunk) + (pa & MSCHUNKS_OFFSET_MASK);
61 }

cheers

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