[ Add Muli, I find his new email in git log]
Hi, Muli
saved_max_pfn is becoming a setback for kexec-tools. Ideally calgary
could get rid of saved_max_pfn at all. But If this can't work, how about
exporting a calgary tce table size to user space, so that kexec-tools
can simply pass calgary=xxx cmdline to 2nd kernel.
What do you think of this problem?
BTW MAINTAINERS file still uses your old email, please update
accordingly.
Thanks
WANG Chao
On 02/19/14 at 02:18pm, WANG Chao wrote:
> Hi, All
>
> arch/x86/kernel/pci-calgary.c is the only user of saved_max_pfn today:
>
> int __init detect_calgary(void)
> {
> [..]
> specified_table_size = determine_tce_table_size((is_kdump_kernel() ?
> saved_max_pfn : max_pfn) * PAGE_SIZE);
> [..]
> }
>
> saved_max_pfn is the real mem size and is calculated by 1st kernel E820
> memmap which is passed in by 2nd kernel's boot_params (done by kexec):
>
> saved_max_pfn = e820_end_of_ram_pfn();
>
> After saved_max_pfn has been set, memmap=exactmap will reset the E820
> provided by boot_params and use the user defined E820 instead.
>
> Now we want to get rid of memmap=exactmap and directly pass the E820
> memmap by boot_params for some reason (eg. exactmap may exceed the cmdline
> size and also isn't compatible with kaslr).
>
> However saved_max_pfn becomes the obstacle for obsoleting exactmap.
> Because it needs two conditions: first kernel's E820 map and
> memmap=exactmap cmdline.
>
> So I'm wondering if it's possible to get rid of saved_max_pfn totally in
> calgary code. Or we can get saved_max_pfn using a different way, for
> example calculated in 1st kernel and passed in to 2nd kernel by cmdline.
>
> Thanks
> WANG Chao
