Re: [PATCH 2/6] mm/page_owner: initialize page owner without holding the zone lock

[Vlastimil Babka]

On 05/03/2016 07:23 AM, js1...@gmail.com wrote:

From: Joonsoo Kim 

It's not necessary to initialized page_owner with holding the zone lock.
It would cause more contention on the zone lock although it's not
a big problem since it is just debug feature. But, it is better
than before so do it. This is also preparation step to use stackdepot
in page owner feature. Stackdepot allocates new pages when there is no
reserved space and holding the zone lock in this case will cause deadlock.


I have same concerns here as for Patch 1/6.

Thanks.

Re: [PATCH 2/6] mm/page_owner: initialize page owner without holding the zone lock

[Vlastimil Babka]

On 05/03/2016 07:23 AM, js1...@gmail.com wrote:

From: Joonsoo Kim 

It's not necessary to initialized page_owner with holding the zone lock.
It would cause more contention on the zone lock although it's not
a big problem since it is just debug feature. But, it is better
than before so do it. This is also preparation step to use stackdepot
in page owner feature. Stackdepot allocates new pages when there is no
reserved space and holding the zone lock in this case will cause deadlock.


I have same concerns here as for Patch 1/6.

Thanks.

[PATCH 2/6] mm/page_owner: initialize page owner without holding the zone lock

[js1304]

From: Joonsoo Kim 

It's not necessary to initialized page_owner with holding the zone lock.
It would cause more contention on the zone lock although it's not
a big problem since it is just debug feature. But, it is better
than before so do it. This is also preparation step to use stackdepot
in page owner feature. Stackdepot allocates new pages when there is no
reserved space and holding the zone lock in this case will cause deadlock.

Signed-off-by: Joonsoo Kim 
---
 mm/compaction.c | 3 +++
 mm/page_alloc.c | 2 --
 mm/page_isolation.c | 9 ++---
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index ecf0252..dbad95b 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -20,6 +20,7 @@
 #include 
 #include 
 #include 
+#include 
 #include "internal.h"
 
 #ifdef CONFIG_COMPACTION
@@ -80,6 +81,8 @@ static void map_pages(struct list_head *list)
arch_alloc_page(page, order);
kernel_map_pages(page, nr_pages, 1);
kasan_alloc_pages(page, order);
+
+   set_page_owner(page, order, __GFP_MOVABLE);
if (order)
split_page(page, order);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 60d7f10..5b632be 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2514,8 +2514,6 @@ int __isolate_free_page(struct page *page, unsigned int 
order)
zone->free_area[order].nr_free--;
rmv_page_order(page);
 
-   set_page_owner(page, order, __GFP_MOVABLE);
-
/* Set the pageblock if the isolated page is at least a pageblock */
if (order >= pageblock_order - 1) {
struct page *endpage = page + (1 << order) - 1;
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 612122b..927f5ee 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -7,6 +7,7 @@
 #include 
 #include 
 #include 
+#include 
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
@@ -108,8 +109,6 @@ static void unset_migratetype_isolate(struct page *page, 
unsigned migratetype)
if (pfn_valid_within(page_to_pfn(buddy)) &&
!is_migrate_isolate_page(buddy)) {
__isolate_free_page(page, order);
-   kernel_map_pages(page, (1 << order), 1);
-   set_page_refcounted(page);
isolated_page = page;
}
}
@@ -128,8 +127,12 @@ static void unset_migratetype_isolate(struct page *page, 
unsigned migratetype)
zone->nr_isolate_pageblock--;
 out:
spin_unlock_irqrestore(>lock, flags);
-   if (isolated_page)
+   if (isolated_page) {
+   kernel_map_pages(page, (1 << order), 1);
+   set_page_refcounted(page);
+   set_page_owner(page, order, __GFP_MOVABLE);
__free_pages(isolated_page, order);
+   }
 }
 
 static inline struct page *
-- 
1.9.1

[PATCH 2/6] mm/page_owner: initialize page owner without holding the zone lock

[js1304]

From: Joonsoo Kim 

It's not necessary to initialized page_owner with holding the zone lock.
It would cause more contention on the zone lock although it's not
a big problem since it is just debug feature. But, it is better
than before so do it. This is also preparation step to use stackdepot
in page owner feature. Stackdepot allocates new pages when there is no
reserved space and holding the zone lock in this case will cause deadlock.

Signed-off-by: Joonsoo Kim 
---
 mm/compaction.c | 3 +++
 mm/page_alloc.c | 2 --
 mm/page_isolation.c | 9 ++---
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index ecf0252..dbad95b 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -20,6 +20,7 @@
 #include 
 #include 
 #include 
+#include 
 #include "internal.h"
 
 #ifdef CONFIG_COMPACTION
@@ -80,6 +81,8 @@ static void map_pages(struct list_head *list)
arch_alloc_page(page, order);
kernel_map_pages(page, nr_pages, 1);
kasan_alloc_pages(page, order);
+
+   set_page_owner(page, order, __GFP_MOVABLE);
if (order)
split_page(page, order);
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 60d7f10..5b632be 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2514,8 +2514,6 @@ int __isolate_free_page(struct page *page, unsigned int 
order)
zone->free_area[order].nr_free--;
rmv_page_order(page);
 
-   set_page_owner(page, order, __GFP_MOVABLE);
-
/* Set the pageblock if the isolated page is at least a pageblock */
if (order >= pageblock_order - 1) {
struct page *endpage = page + (1 << order) - 1;
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 612122b..927f5ee 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -7,6 +7,7 @@
 #include 
 #include 
 #include 
+#include 
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
@@ -108,8 +109,6 @@ static void unset_migratetype_isolate(struct page *page, 
unsigned migratetype)
if (pfn_valid_within(page_to_pfn(buddy)) &&
!is_migrate_isolate_page(buddy)) {
__isolate_free_page(page, order);
-   kernel_map_pages(page, (1 << order), 1);
-   set_page_refcounted(page);
isolated_page = page;
}
}
@@ -128,8 +127,12 @@ static void unset_migratetype_isolate(struct page *page, 
unsigned migratetype)
zone->nr_isolate_pageblock--;
 out:
spin_unlock_irqrestore(>lock, flags);
-   if (isolated_page)
+   if (isolated_page) {
+   kernel_map_pages(page, (1 << order), 1);
+   set_page_refcounted(page);
+   set_page_owner(page, order, __GFP_MOVABLE);
__free_pages(isolated_page, order);
+   }
 }
 
 static inline struct page *
-- 
1.9.1