Home » Mailing list archives » linux-kernel » 2007 » October » 2

[Question] How to represent SYSTEM_RAM in kerenel/resouce.c

Previous thread: [BUG] sky2 errors in 2.6.23-rc9-git1 by Ian Kumlien on Tuesday, October 2, 2007 - 8:42 pm. (15 messages)

Next thread: [PATCH] Document x86-64 iommu kernel parameters by Jeff Garzik on Tuesday, October 2, 2007 - 9:34 pm. (9 messages)
[view original message]
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>
To: LKML <linux-kernel@...>
Cc: <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, Andrew Morton <akpm@...>, <pbadari@...>, linux-ia64@vger.kernel.org <linux-ia64@...>
Subject: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c
Date: Tuesday, October 2, 2007 - 9:31 pm

Hi,


Now, SYSTEM_RAM is registerd to resouce list and a user can see memory map

from /proc/iomem, like following.

==

[kamezawa@drpq linux-2.6.23-rc8-mm2]$ grep RAM /proc/iomem

00000000-0009ffff : System RAM

00100000-03ffffff : System RAM

04000000-04f1bfff : System RAM

04f1c000-6b4b9fff : System RAM

6b4ba000-6b797fff : System RAM

6b798000-6b799fff : System RAM

6b79a000-6b79dfff : System RAM

6b79e000-6b79efff : System RAM

6b79f000-6b7fbfff : System RAM

6b7fc000-6c629fff : System RAM

6c62a000-6c800fff : System RAM

6c801000-6c843fff : System RAM

6c844000-6c847fff : System RAM

6c848000-6c849fff : System RAM

6c84a000-6c85dfff : System RAM

6c85e000-6c85efff : System RAM

6c85f000-6cbfbfff : System RAM

6cbfc000-6d349fff : System RAM

6d34a000-6d3fbfff : System RAM

6d3fc000-6d455fff : System RAM

6d4fc000-6d773fff : System RAM

100000000-7ffffffff : System RAM

4080000000-40ffffffff : System RAM

14004000000-147ffffffff : System RAM

==


But there is a confusion.


i386 and x86_64 registers System RAM as IORESOUCE_MEM | IORESOUCE_BUSY.

ia64 registers System RAM as IORESOURCE_MEM.


Which is better ?


I ask this because current memory hotplug treat memory as IORESOUCE_MEM.

When memory hot-add occurs on x86_64, new memory is added as IORESOUCE_MEM.

memory hot-remove (now) can remove only IORESOUCE_MEM.


If ia64 should treat System RAM as IORESOUCE_MEM | IORESOUCE_BUSY, I'll write

a fix.


Thanks,

-Kame


-
[view original message]
From: Dave Hansen <haveblue@...>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>
Cc: LKML <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, Andrew Morton <akpm@...>, <pbadari@...>, linux-ia64@vger.kernel.org <linux-ia64@...>
Subject: Re: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c
Date: Wednesday, October 3, 2007 - 12:37 pm

I think we should take system ram out of the iomem file, at least.


'struct resource' is a good, cross-platform structure to use for keeping

track of which memory we have where.  So, we can share that structure to

keep track of iomem, or memory hotplug state.  But, I'm not sure we

should be intermingling system RAM and iomem like we are now in the same

instance of the structure.


-- Dave


-
[view original message]
From: Matthew Wilcox <matthew@...>
To: Dave Hansen <haveblue@...>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>, LKML <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, Andrew Morton <akpm@...>, <pbadari@...>, linux-ia64@vger.kernel.org <linux-ia64@...>
Subject: Re: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c
Date: Wednesday, October 3, 2007 - 12:43 pm

Rubbish.  iomem is a representation of the physical addresses in the

system as seen from the CPU's perspective.  As I said in my previous

mail in this thread, if you attempt to map a device's BAR over the top

of physical RAM, things will go poorly for you.


--

Intel are signing my paycheques ... these opinions are still mine

"Bill, look, we understand that you're interested in selling us this

operating system, but compare it to ours.  We can't possibly take such

a retrograde step."

-
[view original message]
From: Matthew Wilcox <matthew@...>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>
Cc: LKML <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, Andrew Morton <akpm@...>, <pbadari@...>, linux-ia64@vger.kernel.org <linux-ia64@...>
Subject: Re: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c
Date: Tuesday, October 2, 2007 - 9:52 pm

Should probably be BUSY.  Non-BUSY regions can have io resources

requested underneath them, but you wouldn't want a PCI device to be

assigned an address which overlaps with physical memory.


--

Intel are signing my paycheques ... these opinions are still mine

"Bill, look, we understand that you're interested in selling us this

operating system, but compare it to ours.  We can't possibly take such

a retrograde step."

-
[view original message]
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>
To: Matthew Wilcox <matthew@...>
Cc: LKML <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, Andrew Morton <akpm@...>, <pbadari@...>, linux-ia64@vger.kernel.org <linux-ia64@...>
Subject: Re: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c
Date: Wednesday, October 3, 2007 - 12:57 am

On Tue, 2 Oct 2007 19:52:42 -0600


Thank you.

It seems that I'll have to try modifing ia64 and memory hotplug in

the next -mm. 


Regards,

-Kame


-
[view original message]
From: Yasunori Goto <y-goto@...>
To: Andrew Morton <akpm@...>
Cc: Matthew Wilcox <matthew@...>, LKML <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, <pbadari@...>, linux-ia64@vger.kernel.org <linux-ia64@...>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>, Dave Hansen <haveblue@...>
Subject: [PATCH] Add IORESOUCE_BUSY flag for System RAM (Re: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c)
Date: Thursday, November 1, 2007 - 5:21 am

Hello.


I was asked from Kame-san to write this patch.


Please apply.


---------

i386 and x86-64 registers System RAM as IORESOURCE_MEM | IORESOURCE_BUSY.


But ia64 registers it as IORESOURCE_MEM only.

In addition, memory hotplug code registers new memory as IORESOURCE_MEM too.


This patch adds IORESOURCE_BUSY for them to avoid potential overlap mapping

by PCI device.


Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>


---

 arch/ia64/kernel/efi.c |    6 ++----

 mm/memory_hotplug.c    |    2 +-

 2 files changed, 3 insertions(+), 5 deletions(-)


Index: current/arch/ia64/kernel/efi.c

===================================================================

--- current.orig/arch/ia64/kernel/efi.c	2007-11-01 15:24:05.000000000 +0900

+++ current/arch/ia64/kernel/efi.c	2007-11-01 15:24:18.000000000 +0900

@@ -1111,7 +1111,7 @@ efi_initialize_iomem_resources(struct re

 		if (md->num_pages == 0) /* should not happen */

 			continue;


-		flags = IORESOURCE_MEM;

+		flags = IORESOURCE_MEM | IORESOURCE_BUSY;

 		switch (md->type) {


 			case EFI_MEMORY_MAPPED_IO:

@@ -1133,12 +1133,11 @@ efi_initialize_iomem_resources(struct re


 			case EFI_ACPI_MEMORY_NVS:

 				name = "ACPI Non-volatile Storage";

-				flags |= IORESOURCE_BUSY;

 				break;


 			case EFI_UNUSABLE_MEMORY:

 				name = "reserved";

-				flags |= IORESOURCE_BUSY | IORESOURCE_DISABLED;

+				flags |= IORESOURCE_DISABLED;

 				break;


 			case EFI_RESERVED_TYPE:

@@ -1147,7 +1146,6 @@ efi_initialize_iomem_resources(struct re

 			case EFI_ACPI_RECLAIM_MEMORY:

 			default:

 				name = "reserved";

-				flags |= IORESOURCE_BUSY;

 				break;

 		}


Index: current/mm/memory_hotplug.c

===================================================================

--- current.orig/mm/memory_hotplug.c	2007-11-01 15:24:16.000000000 +0900

+++ current/mm/memory_hotplug.c	2007-11-01 15:41:27.000000000 +0900

@@ -39,7 +39,7 @@ static struct resource *register_memory_

 	res->name = "System RAM";

 	res->start = start;...
[ message continues ]
[view original message]
From: Badari Pulavarty <pbadari@...>
To: Yasunori Goto <y-goto@...>
Cc: Andrew Morton <akpm@...>, Matthew Wilcox <matthew@...>, lkml <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, linux-ia64@vger.kernel.org <linux-ia64@...>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>, Dave Hansen <haveblue@...>
Subject: Re: [PATCH] Add IORESOUCE_BUSY flag for System RAM (Re: [Question] How to represent SYSTEM_RAM in kerenel/resouce.c)
Date: Thursday, November 1, 2007 - 12:28 pm

Not quite.. You need following patch on top of this to make

hotplug memory remove work on ia64/x86-64.


Thanks,

Badari


Once you mark memory resource BUSY, walk_memory_resource() won't be able

to find it. 


Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>

---

 kernel/resource.c |    2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)


Index: linux-2.6.24-rc1/kernel/resource.c

===================================================================

--- linux-2.6.24-rc1.orig/kernel/resource.c	2007-10-23 20:50:57.000000000 -0700

+++ linux-2.6.24-rc1/kernel/resource.c	2007-11-01 08:19:59.000000000 -0700

@@ -277,7 +277,7 @@ walk_memory_resource(unsigned long start

 	int ret = -1;

 	res.start = (u64) start_pfn << PAGE_SHIFT;

 	res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;

-	res.flags = IORESOURCE_MEM;

+	res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;

 	orig_end = res.end;

 	while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {

 		pfn = (unsigned long)(res.start >> PAGE_SHIFT);


-
[view original message]
From: Yasunori Goto <y-goto@...>
To: Andrew Morton <akpm@...>
Cc: Matthew Wilcox <matthew@...>, lkml <linux-kernel@...>, <andi@...>, linux-mm@kvack.org <linux-mm@...>, tony.luck@intel.com <tony.luck@...>, linux-ia64@vger.kernel.org <linux-ia64@...>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@...>, Dave Hansen <haveblue@...>, Badari Pulavarty <pbadari@...>
Subject: [PATCH] Add IORESOUCE_BUSY flag for System RAM take 2.
Date: Monday, November 5, 2007 - 10:23 pm

Hello.


I merged Baradi-san's patch and mine. This and Kame-san's

following patch is necessary for x86-64 memory unplug.


http://marc.info/?l=linux-mm&m=119399026017901&w=2


I heard Kame-san's patch is already included in -mm.

So, I'll repost merged patch now.


This patch is tested on 2.6.23-mm1.


Please apply.


---


i386 and x86-64 registers System RAM as IORESOURCE_MEM | IORESOURCE_BUSY.


But ia64 registers it as IORESOURCE_MEM only.

In addition, memory hotplug code registers new memory as IORESOURCE_MEM too.


This difference causes a failure of memory unplug of x86-64.

This patch fix it.


This patch adds IORESOURCE_BUSY to avoid potential overlap mapping

by PCI device.


Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>


---

 arch/ia64/kernel/efi.c |    6 ++----

 kernel/resource.c      |    2 +-

 mm/memory_hotplug.c    |    2 +-

 3 files changed, 4 insertions(+), 6 deletions(-)


Index: current/arch/ia64/kernel/efi.c

===================================================================

--- current.orig/arch/ia64/kernel/efi.c	2007-11-02 17:17:30.000000000 +0900

+++ current/arch/ia64/kernel/efi.c	2007-11-02 17:19:10.000000000 +0900

@@ -1111,7 +1111,7 @@ efi_initialize_iomem_resources(struct re

 		if (md->num_pages == 0) /* should not happen */

 			continue;


-		flags = IORESOURCE_MEM;

+		flags = IORESOURCE_MEM | IORESOURCE_BUSY;

 		switch (md->type) {


 			case EFI_MEMORY_MAPPED_IO:

@@ -1133,12 +1133,11 @@ efi_initialize_iomem_resources(struct re


 			case EFI_ACPI_MEMORY_NVS:

 				name = "ACPI Non-volatile Storage";

-				flags |= IORESOURCE_BUSY;

 				break;


 			case EFI_UNUSABLE_MEMORY:

 				name = "reserved";

-				flags |= IORESOURCE_BUSY | IORESOURCE_DISABLED;

+				flags |= IORESOURCE_DISABLED;

 				break;


 			case EFI_RESERVED_TYPE:

@@ -1147,7 +1146,6 @@ efi_initialize_iomem_resources(struct re

 			case EFI_ACPI_RECLAIM_MEMORY:

 			default:

 				name = "r...
[ message continues ]
Previous thread: [BUG] sky2 errors in 2.6.23-rc9-git1 by Ian Kumlien on Tuesday, October 2, 2007 - 8:42 pm. (15 messages)

Next thread: [PATCH] Document x86-64 iommu kernel parameters by Jeff Garzik on Tuesday, October 2, 2007 - 9:34 pm. (9 messages)