memblock:What is the difference between memory and physmem?

memblock:What is the difference between memory and physmem?

[yhb]

[-- Attachment #1: Type: text/plain, Size: 289 bytes --]

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?

[-- Attachment #2: Type: text/html, Size: 2742 bytes --]

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

[Matthew Wilcox]

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.
    
    Signed-off-by: Philipp Hachtmann <phacht@linux.vnet.ibm.com>
    Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

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

[Mike Rapoport]

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.