Re: memblock:What is the difference between memory and physmem?

[Mike Rapoport <rppt@linux.vnet.ibm.com>]

On Sun, Aug 12, 2018 at 07:30:15PM -0700, Matthew Wilcox wrote:
> On Mon, Aug 13, 2018 at 02:23:26AM +0000, yhb@ruijie.com.cn wrote:
> > struct memblock {
> > bool bottom_up; /* is bottom up direction? */
> > phys_addr_t current_limit;
> > struct memblock_type memory;
> > struct memblock_type reserved;
> > #ifdef CONFIG_HAVE_MEMBLOCK_PHYS_MAP
> > struct memblock_type physmem;
> > #endif
> > };
> > What is the difference between memory and physmem?
> 
> commit 70210ed950b538ee7eb811dccc402db9df1c9be4
> Author: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
> Date:   Wed Jan 29 18:16:01 2014 +0100
> 
>     mm/memblock: add physical memory list
>     
>     Add the physmem list to the memblock structure. This list only exists
>     if HAVE_MEMBLOCK_PHYS_MAP is selected and contains the unmodified
>     list of physically available memory. It differs from the memblock
>     memory list as it always contains all memory ranges even if the
>     memory has been restricted, e.g. by use of the mem= kernel parameter.

And it is enabled only for s390
     
>     Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
>     Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
> 

-- 
Sincerely yours,
Mike.