xen: populate correct number of pages when across mem boundary

PATCH In review zhenzhong.duan 3 participants 9 messages Jul 4, 2012 – Jul 18, 2012

Subsystems (3)

x86 virtio core Xen hypervisor x86

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zhenzhong.duan

author

2012-07-04 06:49 UTC #0 lore raw

PATCH 1/1 xen: populate correct number of pages when across mem boundary

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

Also need consider the rare case when xen_do_chunk fail(populate).

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan <[email protected]>

---
 arch/x86/xen/setup.c |   24 +++++++++++-------------
 1 files changed, 11 insertions(+), 13 deletions(-)

arch/x86/xen/setup.c +11 ~~-13~~

index a4790bf..bd78773 100644
@@ -157,50 +157,48 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i < map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;
 
-		if (credits <= 0)
+		if (credits_left <= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);
 
 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn <= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);
 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it
 		 */
+again:
 		if (s_pfn <= max_pfn) {
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn && e_pfn >= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity <= 0)
-			continue;
 
-		if (credits > capacity)
-			credits = capacity;
+		if (credits_left < capacity)
+			capacity = credits_left;
 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
 		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (credits_left > 0 && *last_pfn < e_pfn) {
+			s_pfn = *last_pfn;
+			goto again;
+		}
 	}
 	return done;
 }

Signature · 1 line

1.7.3

David Vrabel

2012-07-12 14:55 UTC #1 lore raw

Quoted 55 lines · zhenzhong.duan

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

Also need consider the rare case when xen_do_chunk fail(populate).

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan <[email protected]>

---
 arch/x86/xen/setup.c |   24 +++++++++++-------------
 1 files changed, 11 insertions(+), 13 deletions(-)

arch/x86/xen/setup.c +0 -1

index a4790bf..bd78773 100644
@@ -157,50 +157,48 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i < map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 171

Quoted 10 lines

arch/x86/xen/setup.c +2 -2

 
-		if (credits <= 0)
+		if (credits_left <= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);

Ok.

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 177

Quoted 7 lines

arch/x86/xen/setup.c +1 -1

 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn <= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);

Ok.

Quoted 23 lines

arch/x86/xen/setup.c +3 -8

 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it
 		 */
+again:
 		if (s_pfn <= max_pfn) {
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn && e_pfn >= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity <= 0)
-			continue;
 
-		if (credits > capacity)
-			credits = capacity;
+		if (credits_left < capacity)
+			capacity = credits_left;

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 201

Quoted 10 lines

arch/x86/xen/setup.c +5 -1

 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
 		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (credits_left > 0 && *last_pfn < e_pfn) {
+			s_pfn = *last_pfn;
+			goto again;
+		}

This looks like it will loop forever if xen_do_chunk() repeatedly fails because Xen is out of pages. I think if xen_do_chunk() cannot get a page from Xen the repopulation process should stop -- aborting this chunk and any others. This will allow the guest to continue to boot just with less memory than expected.

David

zhenzhong.duan

author

2012-07-13 05:37 UTC #2 lore raw

Quoted 116 lines · David Vrabel

Quoted 55 lines · zhenzhong.duan

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

Also need consider the rare case when xen_do_chunk fail(populate).

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

  [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
  [    0.000000] 1-1 mapping on 9e->100
  [    0.000000] 1-1 mapping on cd9ff->100000
  [    0.000000] Released 98 pages of unused memory
  [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
  [    0.000000] BIOS-provided physical RAM map:
  [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
  [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
  [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
  [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
  [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
  [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
  [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan<[email protected]>

---
  arch/x86/xen/setup.c |   24 +++++++++++-------------
  1 files changed, 11 insertions(+), 13 deletions(-)

arch/x86/xen/setup.c +0 -1

index a4790bf..bd78773 100644
@@ -157,50 +157,48 @@ static unsigned long __init xen_populate_chunk(
  	unsigned long dest_pfn;
 
  	for (i = 0, entry = list; i<  map_size; i++, entry++) {
-		unsigned long credits = credits_left;
  		unsigned long s_pfn;
  		unsigned long e_pfn;
  		unsigned long pfns;
  		long capacity;

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 171

Quoted 10 lines

arch/x86/xen/setup.c +2 -2

 
-		if (credits<= 0)
+		if (credits_left<= 0)
  			break;
 
  		if (entry->type != E820_RAM)
  			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);

Ok.

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 177

Quoted 7 lines

arch/x86/xen/setup.c +1 -1

  		/* We only care about E820 after the xen_start_info->nr_pages */
  		if (e_pfn<= max_pfn)
  			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);

Ok.

Quoted 23 lines

arch/x86/xen/setup.c +3 -8

  		/* If the E820 falls within the nr_pages, we want to start
  		 * at the nr_pages PFN.
  		 * If that would mean going past the E820 entry, skip it
  		 */
+again:
  		if (s_pfn<= max_pfn) {
  			capacity = e_pfn - max_pfn;
  			dest_pfn = max_pfn;
  		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn&&  e_pfn>= *last_pfn)
-				s_pfn = *last_pfn;
  			capacity = e_pfn - s_pfn;
  			dest_pfn = s_pfn;
  		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity<= 0)
-			continue;
 
-		if (credits>  capacity)
-			credits = capacity;
+		if (credits_left<  capacity)
+			capacity = credits_left;

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 201

Quoted 10 lines

arch/x86/xen/setup.c +5 -1

 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
  		done += pfns;
  		credits_left -= pfns;
  		*last_pfn = (dest_pfn + pfns);
+		if (credits_left>  0&&  *last_pfn<  e_pfn) {
+			s_pfn = *last_pfn;
+			goto again;
+		}

Quoted 1 line

David

Ok, I'll update the patch, loop forever isn't a good idea.
Originally, I considered the case there is dynamic memory control functionality in the system. thanks for comment.
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zhenzhong.duan

author

2012-07-13 08:31 UTC #3 lore raw

PATCH v2 1/1 xen: populate correct number of pages when across mem boundary

In reply to David Vrabel

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

-v2: If xen_do_chunk fail(populate), abort this chunk and any others. Suggested by David, thanks.

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan<[email protected]>

---

arch/x86/xen/setup.c +9 ~~-14~~

index a4790bf..ead8557 100644
@@ -157,25 +157,24 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i<  map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;
 
-		if (credits<= 0)
+		if (credits_left<= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);
 
 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn<= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);
 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it

@@ -184,23 +183,19 @@ static unsigned long __init xen_populate_chunk(
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn&&  e_pfn>= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity<= 0)
-			continue;
 
-		if (credits>  capacity)
-			credits = capacity;
+		if (credits_left<  capacity)
+			capacity = credits_left;
 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
-		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (pfns<  capacity)
+			break;
+		credits_left -= pfns;
 	}
 	return done;
 }

Signature · 1 line

1.7.3

Konrad Rzeszutek Wilk

2012-07-17 14:45 UTC #4 lore raw

Quoted 32 lines · zhenzhong.duan

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

-v2: If xen_do_chunk fail(populate), abort this chunk and any others. Suggested by David, thanks.

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Quoted 7 lines

Related xen memory layout:
(XEN) Xen-e820 RAM map:
(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)
Signed-off-by Zhenzhong Duan<[email protected]>

Please run this first through scripts/cleanpatch.pl and fix up the issues and then resend.

Thanks!

Quoted 72 lines

---

arch/x86/xen/setup.c +9 ~~-14~~

index a4790bf..ead8557 100644
@@ -157,25 +157,24 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i<  map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;
 
-		if (credits<= 0)
+		if (credits_left<= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);
 
 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn<= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);
 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it

@@ -184,23 +183,19 @@ static unsigned long __init xen_populate_chunk(
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn&&  e_pfn>= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity<= 0)
-			continue;
 
-		if (credits>  capacity)
-			credits = capacity;
+		if (credits_left<  capacity)
+			capacity = credits_left;
 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
-		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (pfns<  capacity)
+			break;
+		credits_left -= pfns;
 	}
 	return done;
 }

Signature · 7 lines

1.7.3

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zhenzhong.duan

author

2012-07-18 02:48 UTC #5 lore raw

PATCH 1/1 xen: populate correct number of pages when across mem boundary

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

-v2: If xen_do_chunk fail(populate), abort this chunk and any others. Suggested by David, thanks.

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan<[email protected]>

---

arch/x86/xen/setup.c +9 ~~-14~~

index a4790bf..ead8557 100644
@@ -157,25 +157,24 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i<  map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;
 
-		if (credits<= 0)
+		if (credits_left<= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);
 
 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn<= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);
 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it

@@ -184,23 +183,19 @@ static unsigned long __init xen_populate_chunk(
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn&&  e_pfn>= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity<= 0)
-			continue;
 
-		if (credits>  capacity)
-			credits = capacity;
+		if (credits_left<  capacity)
+			capacity = credits_left;
 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
-		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (pfns<  capacity)
+			break;
+		credits_left -= pfns;
 	}
 	return done;
 }

Signature · 1 line

1.7.3

zhenzhong.duan

author

2012-07-18 03:08 UTC #6 lore raw

PATCH v2 1/1 xen: populate correct number of pages when across mem boundary

In reply to Konrad Rzeszutek Wilk

From c40ea05842fec8f6caa053b2d58f54608ed0835f Mon Sep 17 00:00:00 2001
From: Zhenzhong Duan<[email protected]>
Date: Wed, 4 Jul 2012 14:08:10 +0800
Subject: [PATCH] xen: populate right count of pages when across mem boundary

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

-v2: If xen_do_chunk fail(populate), abort this chunk and any others. Suggested by David, thanks.

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan<[email protected]>

---

arch/x86/xen/setup.c +9 ~~-14~~

index a4790bf..ead8557 100644
@@ -157,25 +157,24 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i<  map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;
 
-		if (credits<= 0)
+		if (credits_left<= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);
 
 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn<= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);
 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it

@@ -184,23 +183,19 @@ static unsigned long __init xen_populate_chunk(
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn&&  e_pfn>= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity<= 0)
-			continue;
 
-		if (credits>  capacity)
-			credits = capacity;
+		if (credits_left<  capacity)
+			capacity = credits_left;
 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
-		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (pfns<  capacity)
+			break;
+		credits_left -= pfns;
 	}
 	return done;
 }

Signature · 1 line

1.7.3

zhenzhong.duan

author

2012-07-18 04:40 UTC #7 lore raw

Sorry, pls ignore it. Tab still be translated to space.

Quoted 110 lines · zhenzhong.duan

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

-v2: If xen_do_chunk fail(populate), abort this chunk and any others. Suggested by David, thanks.

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

[ 0.000000] Freeing 9e-100 pfn range: 98 pages freed
[ 0.000000] 1-1 mapping on 9e->100
[ 0.000000] 1-1 mapping on cd9ff->100000
[ 0.000000] Released 98 pages of unused memory
[ 0.000000] Set 206435 page(s) to 1-1 mapping
-[ 0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[ 0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[ 0.000000] Populating 100000-100061 pfn range: 97 pages added
[ 0.000000] BIOS-provided physical RAM map:
[ 0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
[ 0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
[ 0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
[ 0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
[ 0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
[ 0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
[ 0.000000] MEMBLOCK configuration:

...
-[ 0.000000] reserved[0x4] [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[ 0.000000] reserved[0x5] [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:
(XEN) 0000000000000000 - 000000000009ec00 (usable) (XEN) 00000000000f0000 - 0000000000100000 (reserved) (XEN) 0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan<[email protected]>

---

arch/x86/xen/setup.c +9 ~~-14~~

index a4790bf..ead8557 100644
@@ -157,25 +157,24 @@ static unsigned long __init xen_populate_chunk(
 unsigned long dest_pfn;
 
 for (i = 0, entry = list; i< map_size; i++, entry++) {
- unsigned long credits = credits_left;
 unsigned long s_pfn;
 unsigned long e_pfn;
 unsigned long pfns;
 long capacity;
 
- if (credits<= 0)
+ if (credits_left<= 0)
 break;
 
 if (entry->type != E820_RAM)
 continue;
 
- e_pfn = PFN_UP(entry->addr + entry->size);
+ e_pfn = PFN_DOWN(entry->addr + entry->size);
 
 /* We only care about E820 after the xen_start_info->nr_pages */
 if (e_pfn<= max_pfn)
 continue;
 
- s_pfn = PFN_DOWN(entry->addr);
+ s_pfn = PFN_UP(entry->addr);
 /* If the E820 falls within the nr_pages, we want to start
 * at the nr_pages PFN.
 * If that would mean going past the E820 entry, skip it

@@ -184,23 +183,19 @@ static unsigned long __init xen_populate_chunk(
 capacity = e_pfn - max_pfn;
 dest_pfn = max_pfn;
 } else {
- /* last_pfn MUST be within E820_RAM regions */
- if (*last_pfn&& e_pfn>= *last_pfn)
- s_pfn = *last_pfn;
 capacity = e_pfn - s_pfn;
 dest_pfn = s_pfn;
 }
- /* If we had filled this E820_RAM entry, go to the next one. */
- if (capacity<= 0)
- continue;
 
- if (credits> capacity)
- credits = capacity;
+ if (credits_left< capacity)
+ capacity = credits_left;
 
- pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+ pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 done += pfns;
- credits_left -= pfns;
 *last_pfn = (dest_pfn + pfns);
+ if (pfns< capacity)
+ break;
+ credits_left -= pfns;
 }
 return done;
 }

David Vrabel

2012-07-12 14:55 UTC #8 lore raw

In reply to zhenzhong.duan

Quoted 55 lines · zhenzhong.duan

When populate pages across a mem boundary at bootup, the page count populated isn't correct. This is due to mem populated to non-mem region and ignored.

Pfn range is also wrongly aligned when mem boundary isn't page aligned.

Also need consider the rare case when xen_do_chunk fail(populate).

For a dom0 booted with dom_mem=3368952K(0xcd9ff000-4k) dmesg diff is:

 [    0.000000] Freeing 9e-100 pfn range: 98 pages freed
 [    0.000000] 1-1 mapping on 9e->100
 [    0.000000] 1-1 mapping on cd9ff->100000
 [    0.000000] Released 98 pages of unused memory
 [    0.000000] Set 206435 page(s) to 1-1 mapping
-[    0.000000] Populating cd9fe-cda00 pfn range: 1 pages added
+[    0.000000] Populating cd9fe-cd9ff pfn range: 1 pages added
+[    0.000000] Populating 100000-100061 pfn range: 97 pages added
 [    0.000000] BIOS-provided physical RAM map:
 [    0.000000] Xen: 0000000000000000 - 000000000009e000 (usable)
 [    0.000000] Xen: 00000000000a0000 - 0000000000100000 (reserved)
 [    0.000000] Xen: 0000000000100000 - 00000000cd9ff000 (usable)
 [    0.000000] Xen: 00000000cd9ffc00 - 00000000cda53c00 (ACPI NVS)
...
 [    0.000000] Xen: 0000000100000000 - 0000000100061000 (usable)
 [    0.000000] Xen: 0000000100061000 - 000000012c000000 (unusable)
...
 [    0.000000] MEMBLOCK configuration:
...
-[    0.000000]  reserved[0x4]       [0x000000cd9ff000-0x000000cd9ffbff], 0xc00 bytes
-[    0.000000]  reserved[0x5]       [0x00000100000000-0x00000100060fff], 0x61000 bytes

Related xen memory layout:
(XEN) Xen-e820 RAM map:

(XEN)  0000000000000000 - 000000000009ec00 (usable)
(XEN)  00000000000f0000 - 0000000000100000 (reserved)
(XEN)  0000000000100000 - 00000000cd9ffc00 (usable)

Signed-off-by Zhenzhong Duan <[email protected]>

---
 arch/x86/xen/setup.c |   24 +++++++++++-------------
 1 files changed, 11 insertions(+), 13 deletions(-)

arch/x86/xen/setup.c +0 -1

index a4790bf..bd78773 100644
@@ -157,50 +157,48 @@ static unsigned long __init xen_populate_chunk(
 	unsigned long dest_pfn;
 
 	for (i = 0, entry = list; i < map_size; i++, entry++) {
-		unsigned long credits = credits_left;
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 		unsigned long pfns;
 		long capacity;

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 171

Quoted 10 lines

arch/x86/xen/setup.c +2 -2

 
-		if (credits <= 0)
+		if (credits_left <= 0)
 			break;
 
 		if (entry->type != E820_RAM)
 			continue;
 
-		e_pfn = PFN_UP(entry->addr + entry->size);
+		e_pfn = PFN_DOWN(entry->addr + entry->size);

Ok.

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 177

Quoted 7 lines

arch/x86/xen/setup.c +1 -1

 		/* We only care about E820 after the xen_start_info->nr_pages */
 		if (e_pfn <= max_pfn)
 			continue;
 
-		s_pfn = PFN_DOWN(entry->addr);
+		s_pfn = PFN_UP(entry->addr);

Ok.

Quoted 23 lines

arch/x86/xen/setup.c +3 -8

 		/* If the E820 falls within the nr_pages, we want to start
 		 * at the nr_pages PFN.
 		 * If that would mean going past the E820 entry, skip it
 		 */
+again:
 		if (s_pfn <= max_pfn) {
 			capacity = e_pfn - max_pfn;
 			dest_pfn = max_pfn;
 		} else {
-			/* last_pfn MUST be within E820_RAM regions */
-			if (*last_pfn && e_pfn >= *last_pfn)
-				s_pfn = *last_pfn;
 			capacity = e_pfn - s_pfn;
 			dest_pfn = s_pfn;
 		}
-		/* If we had filled this E820_RAM entry, go to the next one. */
-		if (capacity <= 0)
-			continue;
 
-		if (credits > capacity)
-			credits = capacity;
+		if (credits_left < capacity)
+			capacity = credits_left;

arch/x86/xen/setup.c static unsigned long __init xen_populate_chunk( · line 201

Quoted 10 lines

arch/x86/xen/setup.c +5 -1

 
-		pfns = xen_do_chunk(dest_pfn, dest_pfn + credits, false);
+		pfns = xen_do_chunk(dest_pfn, dest_pfn + capacity, false);
 		done += pfns;
 		credits_left -= pfns;
 		*last_pfn = (dest_pfn + pfns);
+		if (credits_left > 0 && *last_pfn < e_pfn) {
+			s_pfn = *last_pfn;
+			goto again;
+		}

David