mm/kmemleak: Avoid scanning potential huge holes

When using devm_request_free_mem_region() and devm_memremap_pages() to add ZONE_DEVICE memory, if requested free mem region pfn were huge(e.g., 0x0x400000000 ,we found on some amd apus, amdkfd svm will request a such free mem region), the node_end_pfn() will be also huge(see move_pfn_range_to_zone()). It creates a huge hole between node_start_pfn() and node_end_pfn().

In such a case, following code snippet acctually was just doing busy test_bit() looping on the huge hole.

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
}

So we got a soft lockup:

 watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
 CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
 RIP: 0010:pfn_to_online_page+0x5/0xd0
 Call Trace:
  ? kmemleak_scan+0x16a/0x440
  kmemleak_write+0x306/0x3a0
  ? common_file_perm+0x72/0x170
  full_proxy_write+0x5c/0x90
  vfs_write+0xb9/0x260
  ksys_write+0x67/0xe0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x3b/0xc0
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

real    0m0.976s
user    0m0.000s
sys     0m0.968s

after the patch:

real    0m0.981s
user    0m0.000s
sys     0m0.973s

(2) amdgpu module loaded

before the patch:

real    0m35.365s
user    0m0.000s
sys     0m35.354s

after the patch:

real    0m1.049s
user    0m0.000s
sys     0m1.042s

Signed-off-by Lang Yu <[email protected]>

---
 mm/kmemleak.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/kmemleak.c +4 -3

index b57383c17cf6..d07444613a84 100644
@@ -1403,6 +1403,7 @@ static void kmemleak_scan(void)
 {
 	unsigned long flags;
 	struct kmemleak_object *object;
+	struct zone *zone;
 	int i;
 	int new_leaks = 0;
 

@@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
 	 * Struct page scanning for each node.
 	 */
 	get_online_mems();
-	for_each_online_node(i) {
-		unsigned long start_pfn = node_start_pfn(i);
-		unsigned long end_pfn = node_end_pfn(i);
+	for_each_populated_zone(zone) {
+		unsigned long start_pfn = zone->zone_start_pfn;
+		unsigned long end_pfn = zone_end_pfn(zone);
 		unsigned long pfn;
 
 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {

Quoted 94 lines · Lang Yu

When using devm_request_free_mem_region() and devm_memremap_pages() to add ZONE_DEVICE memory, if requested free mem region pfn were huge(e.g., 0x400000000 ,we found on some amd apus, amdkfd svm will request a such free mem region), the node_end_pfn() will be also huge(see move_pfn_range_to_zone()). It creates a huge hole between node_start_pfn() and node_end_pfn().

In such a case, following code snippet acctually was just doing busy test_bit() looping on the huge hole.

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
}

So we got a soft lockup:

 watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
 CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
 RIP: 0010:pfn_to_online_page+0x5/0xd0
 Call Trace:
  ? kmemleak_scan+0x16a/0x440
  kmemleak_write+0x306/0x3a0
  ? common_file_perm+0x72/0x170
  full_proxy_write+0x5c/0x90
  vfs_write+0xb9/0x260
  ksys_write+0x67/0xe0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x3b/0xc0
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

real    0m0.976s
user    0m0.000s
sys     0m0.968s

after the patch:

real    0m0.981s
user    0m0.000s
sys     0m0.973s

(2) amdgpu module loaded

before the patch:

real    0m35.365s
user    0m0.000s
sys     0m35.354s

after the patch:

real    0m1.049s
user    0m0.000s
sys     0m1.042s

Signed-off-by Lang Yu <[email protected]>

---
 mm/kmemleak.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/kmemleak.c +4 -3

index b57383c17cf6..d07444613a84 100644
@@ -1403,6 +1403,7 @@ static void kmemleak_scan(void)
 {
 	unsigned long flags;
 	struct kmemleak_object *object;
+	struct zone *zone;
 	int i;
 	int new_leaks = 0;
 

@@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
 	 * Struct page scanning for each node.
 	 */
 	get_online_mems();
-	for_each_online_node(i) {
-		unsigned long start_pfn = node_start_pfn(i);
-		unsigned long end_pfn = node_end_pfn(i);
+	for_each_populated_zone(zone) {
+		unsigned long start_pfn = zone->zone_start_pfn;
+		unsigned long end_pfn = zone_end_pfn(zone);
 		unsigned long pfn;
 
 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {

mm/kmemleak.c static void kmemleak_scan(void) · line 1459

Quoted 5 lines

mm/kmemleak.c +1 -1

@@ -1455,7 +1456,7 @@ static void kmemleak_scan(void)
 				continue;
 
 			/* only scan pages belonging to this node */
-			if (page_to_nid(page) != i)
+			if (page_to_nid(page) != zone_to_nid(zone))

With overlapping zones you might rescan ranges ... instead we should do:

/* only scan pages belonging to this zone */
if (zone != page_zone(page))

	...

Or alternatively:

/* only scan pages belonging to this node */
if (page_to_nid(page) != zone_to_nid(zone))

	continue;
/* only scan pages belonging to this zone */
if (page_zonenum(page) != zone_idx(zone))
	continue;

Signature · 3 lines

Thanks,

David / dhildenb

Quoted 107 lines · David Hildenbrand

Quoted 94 lines · Lang Yu

When using devm_request_free_mem_region() and devm_memremap_pages() to add ZONE_DEVICE memory, if requested free mem region pfn were huge(e.g., 0x400000000 ,we found on some amd apus, amdkfd svm will request a such free mem region), the node_end_pfn() will be also huge(see move_pfn_range_to_zone()). It creates a huge hole between node_start_pfn() and node_end_pfn().

In such a case, following code snippet acctually was just doing busy test_bit() looping on the huge hole.

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
}

So we got a soft lockup:

 watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
 CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
 RIP: 0010:pfn_to_online_page+0x5/0xd0
 Call Trace:
  ? kmemleak_scan+0x16a/0x440
  kmemleak_write+0x306/0x3a0
  ? common_file_perm+0x72/0x170
  full_proxy_write+0x5c/0x90
  vfs_write+0xb9/0x260
  ksys_write+0x67/0xe0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x3b/0xc0
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

real    0m0.976s
user    0m0.000s
sys     0m0.968s

after the patch:

real    0m0.981s
user    0m0.000s
sys     0m0.973s

(2) amdgpu module loaded

before the patch:

real    0m35.365s
user    0m0.000s
sys     0m35.354s

after the patch:

real    0m1.049s
user    0m0.000s
sys     0m1.042s

Signed-off-by Lang Yu <[email protected]>

---
 mm/kmemleak.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/kmemleak.c +4 -3

index b57383c17cf6..d07444613a84 100644
@@ -1403,6 +1403,7 @@ static void kmemleak_scan(void)
 {
 	unsigned long flags;
 	struct kmemleak_object *object;
+	struct zone *zone;
 	int i;
 	int new_leaks = 0;
 

@@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
 	 * Struct page scanning for each node.
 	 */
 	get_online_mems();
-	for_each_online_node(i) {
-		unsigned long start_pfn = node_start_pfn(i);
-		unsigned long end_pfn = node_end_pfn(i);
+	for_each_populated_zone(zone) {
+		unsigned long start_pfn = zone->zone_start_pfn;
+		unsigned long end_pfn = zone_end_pfn(zone);
 		unsigned long pfn;
 
 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {

mm/kmemleak.c static void kmemleak_scan(void) · line 1459

Quoted 5 lines

mm/kmemleak.c +1 -1

@@ -1455,7 +1456,7 @@ static void kmemleak_scan(void)
 				continue;
 
 			/* only scan pages belonging to this node */
-			if (page_to_nid(page) != i)
+			if (page_to_nid(page) != zone_to_nid(zone))

With overlapping zones you might rescan ranges ... instead we should do:

/* only scan pages belonging to this zone */
if (zone != page_zone(page))

	...

Quoted 8 lines

Or alternatively:

/* only scan pages belonging to this node */
if (page_to_nid(page) != zone_to_nid(zone))

	continue;
/* only scan pages belonging to this zone */
if (page_zonenum(page) != zone_idx(zone))
	continue;

The original code has covered that, i.e.,
only scan pages belonging to this node.
I didn't change that behavior.

Quoted 117 lines · Lang Yu

Quoted 107 lines · David Hildenbrand

Quoted 94 lines · Lang Yu

When using devm_request_free_mem_region() and devm_memremap_pages() to add ZONE_DEVICE memory, if requested free mem region pfn were huge(e.g., 0x400000000 ,we found on some amd apus, amdkfd svm will request a such free mem region), the node_end_pfn() will be also huge(see move_pfn_range_to_zone()). It creates a huge hole between node_start_pfn() and node_end_pfn().

In such a case, following code snippet acctually was just doing busy test_bit() looping on the huge hole.

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
}

So we got a soft lockup:

 watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
 CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
 RIP: 0010:pfn_to_online_page+0x5/0xd0
 Call Trace:
  ? kmemleak_scan+0x16a/0x440
  kmemleak_write+0x306/0x3a0
  ? common_file_perm+0x72/0x170
  full_proxy_write+0x5c/0x90
  vfs_write+0xb9/0x260
  ksys_write+0x67/0xe0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x3b/0xc0
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

real    0m0.976s
user    0m0.000s
sys     0m0.968s

after the patch:

real    0m0.981s
user    0m0.000s
sys     0m0.973s

(2) amdgpu module loaded

before the patch:

real    0m35.365s
user    0m0.000s
sys     0m35.354s

after the patch:

real    0m1.049s
user    0m0.000s
sys     0m1.042s

Signed-off-by Lang Yu <[email protected]>

---
 mm/kmemleak.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/kmemleak.c +4 -3

index b57383c17cf6..d07444613a84 100644
@@ -1403,6 +1403,7 @@ static void kmemleak_scan(void)
 {
 	unsigned long flags;
 	struct kmemleak_object *object;
+	struct zone *zone;
 	int i;
 	int new_leaks = 0;
 

@@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
 	 * Struct page scanning for each node.
 	 */
 	get_online_mems();
-	for_each_online_node(i) {
-		unsigned long start_pfn = node_start_pfn(i);
-		unsigned long end_pfn = node_end_pfn(i);
+	for_each_populated_zone(zone) {
+		unsigned long start_pfn = zone->zone_start_pfn;
+		unsigned long end_pfn = zone_end_pfn(zone);
 		unsigned long pfn;
 
 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {

mm/kmemleak.c static void kmemleak_scan(void) · line 1459

Quoted 5 lines

mm/kmemleak.c +1 -1

@@ -1455,7 +1456,7 @@ static void kmemleak_scan(void)
 				continue;
 
 			/* only scan pages belonging to this node */
-			if (page_to_nid(page) != i)
+			if (page_to_nid(page) != zone_to_nid(zone))

With overlapping zones you might rescan ranges ... instead we should do:

/* only scan pages belonging to this zone */
if (zone != page_zone(page))

	...

Quoted 8 lines

Or alternatively:

/* only scan pages belonging to this node */
if (page_to_nid(page) != zone_to_nid(zone))

	continue;
/* only scan pages belonging to this zone */
if (page_zonenum(page) != zone_idx(zone))
	continue;

Quoted 3 lines

The original code has covered that, i.e.,
only scan pages belonging to this node.
I didn't change that behavior.

Again, you can easily have overlapping zones -- ZONE_NORMAL and ZONE_MOVABLE -- in which case, a PFN is spanned by multiple zones, but only belongs to a single zone.

The original code would scan each PFN exactly once, as it was iterating the node PFNs. Your changed code might scan a single PFN multiple times, if it's spanned by multiple zones.

Signature · 3 lines

Thanks,

David / dhildenb

Quoted 126 lines · David Hildenbrand

Quoted 117 lines · Lang Yu

Quoted 107 lines · David Hildenbrand

Quoted 94 lines · Lang Yu

When using devm_request_free_mem_region() and devm_memremap_pages() to add ZONE_DEVICE memory, if requested free mem region pfn were huge(e.g., 0x400000000 ,we found on some amd apus, amdkfd svm will request a such free mem region), the node_end_pfn() will be also huge(see move_pfn_range_to_zone()). It creates a huge hole between node_start_pfn() and node_end_pfn().

In such a case, following code snippet acctually was just doing busy test_bit() looping on the huge hole.

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
}

So we got a soft lockup:

 watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
 CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
 RIP: 0010:pfn_to_online_page+0x5/0xd0
 Call Trace:
  ? kmemleak_scan+0x16a/0x440
  kmemleak_write+0x306/0x3a0
  ? common_file_perm+0x72/0x170
  full_proxy_write+0x5c/0x90
  vfs_write+0xb9/0x260
  ksys_write+0x67/0xe0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x3b/0xc0
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

real    0m0.976s
user    0m0.000s
sys     0m0.968s

after the patch:

real    0m0.981s
user    0m0.000s
sys     0m0.973s

(2) amdgpu module loaded

before the patch:

real    0m35.365s
user    0m0.000s
sys     0m35.354s

after the patch:

real    0m1.049s
user    0m0.000s
sys     0m1.042s

Signed-off-by Lang Yu <[email protected]>

---
 mm/kmemleak.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/kmemleak.c +4 -3

index b57383c17cf6..d07444613a84 100644
@@ -1403,6 +1403,7 @@ static void kmemleak_scan(void)
 {
 	unsigned long flags;
 	struct kmemleak_object *object;
+	struct zone *zone;
 	int i;
 	int new_leaks = 0;
 

@@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
 	 * Struct page scanning for each node.
 	 */
 	get_online_mems();
-	for_each_online_node(i) {
-		unsigned long start_pfn = node_start_pfn(i);
-		unsigned long end_pfn = node_end_pfn(i);
+	for_each_populated_zone(zone) {
+		unsigned long start_pfn = zone->zone_start_pfn;
+		unsigned long end_pfn = zone_end_pfn(zone);
 		unsigned long pfn;
 
 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {

mm/kmemleak.c static void kmemleak_scan(void) · line 1459

Quoted 5 lines

mm/kmemleak.c +1 -1

@@ -1455,7 +1456,7 @@ static void kmemleak_scan(void)
 				continue;
 
 			/* only scan pages belonging to this node */
-			if (page_to_nid(page) != i)
+			if (page_to_nid(page) != zone_to_nid(zone))

With overlapping zones you might rescan ranges ... instead we should do:

/* only scan pages belonging to this zone */
if (zone != page_zone(page))

	...

Quoted 8 lines

Or alternatively:

/* only scan pages belonging to this node */
if (page_to_nid(page) != zone_to_nid(zone))

	continue;
/* only scan pages belonging to this zone */
if (page_zonenum(page) != zone_idx(zone))
	continue;

Quoted 3 lines

The original code has covered that, i.e.,
only scan pages belonging to this node.
I didn't change that behavior.

Again, you can easily have overlapping zones -- ZONE_NORMAL and ZONE_MOVABLE -- in which case, a PFN is spanned by multiple zones, but only belongs to a single zone.

Quoted 4 lines

The original code would scan each PFN exactly once, as it was iterating the node PFNs. Your changed code might scan a single PFN multiple times, if it's spanned by multiple zones.

Did you mean a single PFN is shared by multiple zones belonging to the same node here? Thanks!

Quoted 127 lines · Lang Yu

Quoted 126 lines · David Hildenbrand

Quoted 117 lines · Lang Yu

Quoted 107 lines · David Hildenbrand

Quoted 94 lines · Lang Yu

When using devm_request_free_mem_region() and devm_memremap_pages() to add ZONE_DEVICE memory, if requested free mem region pfn were huge(e.g., 0x400000000 ,we found on some amd apus, amdkfd svm will request a such free mem region), the node_end_pfn() will be also huge(see move_pfn_range_to_zone()). It creates a huge hole between node_start_pfn() and node_end_pfn().

In such a case, following code snippet acctually was just doing busy test_bit() looping on the huge hole.

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
	struct page *page = pfn_to_online_page(pfn);
		if (!page)
			continue;
	...
}

So we got a soft lockup:

 watchdog: BUG: soft lockup - CPU#6 stuck for 26s! [bash:1221]
 CPU: 6 PID: 1221 Comm: bash Not tainted 5.15.0-custom #1
 RIP: 0010:pfn_to_online_page+0x5/0xd0
 Call Trace:
  ? kmemleak_scan+0x16a/0x440
  kmemleak_write+0x306/0x3a0
  ? common_file_perm+0x72/0x170
  full_proxy_write+0x5c/0x90
  vfs_write+0xb9/0x260
  ksys_write+0x67/0xe0
  __x64_sys_write+0x1a/0x20
  do_syscall_64+0x3b/0xc0
  entry_SYSCALL_64_after_hwframe+0x44/0xae

I did some tests with the patch.

(1) amdgpu module unloaded

before the patch:

real    0m0.976s
user    0m0.000s
sys     0m0.968s

after the patch:

real    0m0.981s
user    0m0.000s
sys     0m0.973s

(2) amdgpu module loaded

before the patch:

real    0m35.365s
user    0m0.000s
sys     0m35.354s

after the patch:

real    0m1.049s
user    0m0.000s
sys     0m1.042s

Signed-off-by Lang Yu <[email protected]>

---
 mm/kmemleak.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

mm/kmemleak.c +4 -3

index b57383c17cf6..d07444613a84 100644
@@ -1403,6 +1403,7 @@ static void kmemleak_scan(void)
 {
 	unsigned long flags;
 	struct kmemleak_object *object;
+	struct zone *zone;
 	int i;
 	int new_leaks = 0;
 

@@ -1443,9 +1444,9 @@ static void kmemleak_scan(void)
 	 * Struct page scanning for each node.
 	 */
 	get_online_mems();
-	for_each_online_node(i) {
-		unsigned long start_pfn = node_start_pfn(i);
-		unsigned long end_pfn = node_end_pfn(i);
+	for_each_populated_zone(zone) {
+		unsigned long start_pfn = zone->zone_start_pfn;
+		unsigned long end_pfn = zone_end_pfn(zone);
 		unsigned long pfn;
 
 		for (pfn = start_pfn; pfn < end_pfn; pfn++) {

mm/kmemleak.c static void kmemleak_scan(void) · line 1459

Quoted 5 lines

mm/kmemleak.c +1 -1

@@ -1455,7 +1456,7 @@ static void kmemleak_scan(void)
 				continue;
 
 			/* only scan pages belonging to this node */
-			if (page_to_nid(page) != i)
+			if (page_to_nid(page) != zone_to_nid(zone))

With overlapping zones you might rescan ranges ... instead we should do:

/* only scan pages belonging to this zone */
if (zone != page_zone(page))

	...

Quoted 8 lines

Or alternatively:

/* only scan pages belonging to this node */
if (page_to_nid(page) != zone_to_nid(zone))

	continue;
/* only scan pages belonging to this zone */
if (page_zonenum(page) != zone_idx(zone))
	continue;

Quoted 3 lines

The original code has covered that, i.e.,
only scan pages belonging to this node.
I didn't change that behavior.

Again, you can easily have overlapping zones -- ZONE_NORMAL and ZONE_MOVABLE -- in which case, a PFN is spanned by multiple zones, but only belongs to a single zone.

Quoted 7 lines

Quoted 4 lines

The original code would scan each PFN exactly once, as it was iterating the node PFNs. Your changed code might scan a single PFN multiple times, if it's spanned by multiple zones.

Did you mean a single PFN is shared by multiple zones belonging to the same node here? Thanks!

Not shared, spanned. A PFN always belongs to exactly one ZONE+NODE, but might be "spanned" by multiple nodes or multiple zones, because nodes and zones can overlap We can get the actual zone of a PFN via page_zone(page) in my example above. Note that checking for the zone structure (not the zone number/idx) implicitly checks for the node.

Let's take a look at an example:

...
[root@vm-0 ~]# cat /sys/devices/system/memory/memory32/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory33/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory34/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory35/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory36/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory37/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory38/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory39/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory40/valid_zones Movable
[root@vm-0 ~]# cat /sys/devices/system/memory/memory41/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory42/valid_zones Movable
[root@vm-0 ~]# cat /sys/devices/system/memory/memory43/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory44/valid_zones Movable
[root@vm-0 ~]# cat /sys/devices/system/memory/memory45/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory46/valid_zones Movable
[root@vm-0 ~]# cat /sys/devices/system/memory/memory47/valid_zones Normal
[root@vm-0 ~]# cat /sys/devices/system/memory/memory48/valid_zones

# cat /proc/zoneinfo
Node 0, zone      DMA
	...
        spanned  4095
        present  3998
        managed  3977
	...
  start_pfn:           1
Node 0, zone    DMA32
	...
        spanned  1044480
        present  782304
        managed  765920
	...
  start_pfn:           4096
Node 0, zone   Normal
	...
        spanned  524288
        present  393216
        managed  365736
	...
  start_pfn:           1048576
Node 0, zone  Movable
	...
        spanned  229376
        present  131072
        managed  131072
  start_pfn:           1310720

So Normal spans:

1048576 -> 1572863

And Movable spans:

1310720 -> 1540095

Both zones overlap.

Signature · 3 lines

Thanks,

David / dhildenb