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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: [PATCH 3/5] xen: allow balloon driver to use more than one memory region
On Fri, Aug 19, 2011 at 03:57:18PM +0100, David Vrabel wrote:
> Allow the xen balloon driver to populate its list of extra pages from
> more than one region of memory. This will allow platforms to provide
> (for example) a region of low memory and a region of high memory.
>
> The maximum possible number of extra regions is 128 (== E820MAX) which
> is quite large so xen_extra_mem is placed in __initdata. This is safe
> as both xen_memeory_setup() and balloon_init() are in __init.
^^^^^^ memory.
>
> The balloon regions themselves are not altered (i.e., there is still
> only the one region).
>
> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> ---
> arch/x86/xen/setup.c | 20 +++++++++---------
> drivers/xen/balloon.c | 51 ++++++++++++++++++++++++++++--------------------
> include/xen/page.h | 9 +++++++-
> 3 files changed, 48 insertions(+), 32 deletions(-)
>
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index c3b8d44..4720c2d 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -37,7 +37,7 @@ extern void xen_syscall_target(void);
> extern void xen_syscall32_target(void);
>
> /* Amount of extra memory space we add to the e820 ranges */
> -phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
> +struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
>
> /*
> * The maximum amount of extra memory compared to the base size. The
> @@ -56,7 +56,7 @@ static void __init xen_add_extra_mem(unsigned long pages)
> unsigned long pfn;
>
> u64 size = (u64)pages * PAGE_SIZE;
> - u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
> + u64 extra_start = xen_extra_mem[0].start + xen_extra_mem[0].size;
>
> if (!pages)
> return;
> @@ -66,7 +66,7 @@ static void __init xen_add_extra_mem(unsigned long pages)
>
> memblock_x86_reserve_range(extra_start, extra_start + size, "XEN
> EXTRA");
>
> - xen_extra_mem_size += size;
> + xen_extra_mem[0].size += size;
>
> xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
>
> @@ -239,7 +239,7 @@ char * __init xen_memory_setup(void)
>
> memcpy(map_raw, map, sizeof(map));
> e820.nr_map = 0;
> - xen_extra_mem_start = mem_end;
> + xen_extra_mem[0].start = mem_end;
> for (i = 0; i < memmap.nr_entries; i++) {
> unsigned long long end;
>
> @@ -267,8 +267,8 @@ char * __init xen_memory_setup(void)
> e820_add_region(end, delta, E820_UNUSABLE);
> }
>
> - if (map[i].size > 0 && end > xen_extra_mem_start)
> - xen_extra_mem_start = end;
> + if (map[i].size > 0 && end > xen_extra_mem[0].start)
> + xen_extra_mem[0].start = end;
>
> /* Add region if any remains */
> if (map[i].size > 0)
> @@ -276,10 +276,10 @@ char * __init xen_memory_setup(void)
> }
> /* Align the balloon area so that max_low_pfn does not get set
> * to be at the _end_ of the PCI gap at the far end (fee01000).
> - * Note that xen_extra_mem_start gets set in the loop above to be
> - * past the last E820 region. */
> - if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32)))
> - xen_extra_mem_start = (1ULL<<32);
> + * Note that the start of balloon area gets set in the loop above
> + * to be past the last E820 region. */
> + if (xen_initial_domain() && (xen_extra_mem[0].start < (1ULL<<32)))
> + xen_extra_mem[0].start = (1ULL<<32);
>
> /*
> * In domU, the ISA region is normal, usable memory, but we
> diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
> index 5814022..996cf65 100644
> --- a/drivers/xen/balloon.c
> +++ b/drivers/xen/balloon.c
> @@ -555,11 +555,35 @@ void free_xenballooned_pages(int nr_pages, struct
> page** pages)
> }
> EXPORT_SYMBOL(free_xenballooned_pages);
>
> -static int __init balloon_init(void)
> +static void __init balloon_add_memory_region(unsigned long start_pfn,
> unsigned long pages)
That looks suspiciously like it has more than 80 lines. You ran the
_all_ of the patches through scripts/checkpath.pl right?
> {
> - domid_t domid = DOMID_SELF;
> unsigned long pfn, extra_pfn_end;
> struct page *page;
> +
> + /*
> + * Initialise the balloon with excess memory space. We need
> + * to make sure we don't add memory which doesn't exist or
> + * logically exist. The E820 map can be trimmed to be smaller
> + * than the amount of physical memory due to the mem= command
> + * line parameter. And if this is a 32-bit non-HIGHMEM kernel
> + * on a system with memory which requires highmem to access,
> + * don't try to use it.
That whole comment is just confusing.. But I do know that you
just moved it, but I wonder if it makes sense to remove it or
alter it in the future.
> + */
> + extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()),
> + start_pfn + pages);
> + for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) {
> + page = pfn_to_page(pfn);
> + /* totalram_pages and totalhigh_pages do not
> + include the boot-time balloon extension, so
> + don't subtract from it. */
> + __balloon_append(page);
> + }
> +}
> +
> +static int __init balloon_init(void)
> +{
> + domid_t domid = DOMID_SELF;
> + int i;
> int ret;
>
> if (!xen_domain())
> @@ -588,25 +612,10 @@ static int __init balloon_init(void)
> register_memory_notifier(&xen_memory_nb);
> #endif
>
> - /*
> - * Initialise the balloon with excess memory space. We need
> - * to make sure we don't add memory which doesn't exist or
> - * logically exist. The E820 map can be trimmed to be smaller
> - * than the amount of physical memory due to the mem= command
> - * line parameter. And if this is a 32-bit non-HIGHMEM kernel
> - * on a system with memory which requires highmem to access,
> - * don't try to use it.
> - */
> - extra_pfn_end = min(min(max_pfn, e820_end_of_ram_pfn()),
> - (unsigned long)PFN_DOWN(xen_extra_mem_start +
> xen_extra_mem_size));
> - for (pfn = PFN_UP(xen_extra_mem_start);
> - pfn < extra_pfn_end;
> - pfn++) {
> - page = pfn_to_page(pfn);
> - /* totalram_pages and totalhigh_pages do not include the
> boot-time
> - balloon extension, so don't subtract from it. */
> - __balloon_append(page);
> - }
> + for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++)
> + if (xen_extra_mem[i].size)
> +
> balloon_add_memory_region(PFN_UP(xen_extra_mem[i].start),
> +
> PFN_DOWN(xen_extra_mem[i].size));
>
> return 0;
> }
> diff --git a/include/xen/page.h b/include/xen/page.h
> index 0be36b9..b432c03 100644
> --- a/include/xen/page.h
> +++ b/include/xen/page.h
> @@ -3,6 +3,13 @@
>
> #include <asm/xen/page.h>
>
> -extern phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
> +struct xen_memory_region {
> + phys_addr_t start;
> + phys_addr_t size;
> +};
> +
> +#define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820MAX */
> +
> +extern struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS];
__initdata
>
> #endif /* _XEN_PAGE_H */
> --
> 1.7.2.5
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