Re: [Patch v3] Add persistent memory support

[Dave Young <dyoung@redhat.com>]

On 08/20/15 at 10:52am, Baoquan He wrote:
> On 08/20/15 at 10:38am, Dave Young wrote:
> > On 08/19/15 at 06:45pm, Baoquan He wrote:
> > > On 08/19/15 at 05:28pm, Dave Young wrote:
> > > > Hi,
> > > > 
> > > > On 08/19/15 at 05:03pm, Baoquan He wrote:
> > >   
> > > > > diff --git a/kexec/arch/i386/crashdump-x86.c b/kexec/arch/i386/crashdump-x86.c
> > > > > index 82bf239..598a78f 100644
> > > > > --- a/kexec/arch/i386/crashdump-x86.c
> > > > > +++ b/kexec/arch/i386/crashdump-x86.c
> > > > > @@ -301,6 +301,10 @@ static int get_crash_memory_ranges(struct memory_range **range, int *ranges,
> > > > >  			type = RANGE_ACPI;
> > > > >  		} else if(memcmp(str,"ACPI Non-volatile Storage\n",26) == 0 ) {
> > > > >  			type = RANGE_ACPI_NVS;
> > > > > +		} else if(memcmp(str,"Persistent Memory (legacy)\n",27) == 0 ) {
> > > > > +			type = RANGE_PRAM;
> > > > > +		} else if(memcmp(str,"Persistent Memory\n",18) == 0 ) {
> > > > > +			type = RANGE_PMEM;
> > > > >  		} else if(memcmp(str,"reserved\n",9) == 0 ) {
> > > > >  			type = RANGE_RESERVED;
> > > > >  		} else if (memcmp(str, "GART\n", 5) == 0) {
> > > > > @@ -640,6 +644,8 @@ static void cmdline_add_memmap_internal(char *cmdline, unsigned long startk,
> > > > >  		strcat (str_mmap, "K$");
> > > > >  	else if (type == RANGE_ACPI || type == RANGE_ACPI_NVS)
> > > > >  		strcat (str_mmap, "K#");
> > > > > +	else if (type == RANGE_PRAM)
> > > > > +		strcat (str_mmap, "K!");
> > > > 
> > > > Since we have switched to use e820 it is not necessary to supporting new things
> > > > in legacy memmap interface?
> > > 
> > > Well, I am not sure about this. Kexec-tools provides memmap method to
> > > pass the memory ranges, then either we continue supporting it or we
> > > delete it. Now is this OK we just keep legacy memmap code there and
> > > ignore it? If people check the man page and find --pass-memmap-cmdline
> > > and intend to try, then kexec/kdump fail, then how do we go with it?
> > 
> > It is a legacy interface, IMO we should deprecate it and remove it after a
> > period like several release cycle.
> 
> So if customers still want to specify memmap there isn't a way.
> 

Why do one use memmap with new kexec-tools?

There's no reason to use the old interface, I do not think there's any benefit
since new interface works well and be more scalable.

Thanks
Dave

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