Juergen Gross, on Fri 05 Aug 2016 19:35:45 +0200, wrote:
> The first free pfn available for allocation is calculated by adding the
> number of page table frames to the pfn of the first page table and
> then the magic number 3 to account for start info page et al.
>
> As the start info page, xenstore page and console page are allocated
> _before_ the page tables leaving room for these pages behind the page
> tables makes no sense.
Ah, it seems this dates back a very long time ago indeed.
> Signed-off-by: Juergen Gross
> Reviewed-by: Wei Liu
Acked-by: Samuel Thibault
> ---
> arch/x86/mm.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/mm.c b/arch/x86/mm.c
> index 51aa966..ae1036e 100644
> --- a/arch/x86/mm.c
> +++ b/arch/x86/mm.c
> @@ -867,9 +867,8 @@ void arch_init_mm(unsigned long* start_pfn_p, unsigned
> long* max_pfn_p)
> printk("stack start: %p(VA)\n", stack);
> printk(" _end: %p(VA)\n", &_end);
>
> -/* First page follows page table pages and 3 more pages (store page etc)
> */
> -start_pfn = PFN_UP(to_phys(start_info.pt_base)) +
> -start_info.nr_pt_frames + 3;
> +/* First page follows page table pages. */
> +start_pfn = PFN_UP(to_phys(start_info.pt_base)) +
> start_info.nr_pt_frames;
> max_pfn = start_info.nr_pages;
>
> /* We need room for demand mapping and heap, clip available memory */
> --
> 2.6.6
>
--
Samuel
hiri, le cri ici, c des marrants
j'ai un rep ".uglyhackdirectorywithoutacls" ds mon home
-+- #ens-mim en stage -+-
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