[-mm PATCH 9/9] Memory controller make page_referenced() container aware (v6)

Balbir Singh
2007-08-17T08:47:54Z

Make page_referenced() container aware. Without this patch, page_referenced()
can cause a page to be skipped while reclaiming pages. This patch
ensures that other containers do not hold pages in a particular container
hostage. It is required to ensure that shared pages are freed from a container
when they are not actively referenced from the container that brought
them in

Signed-off-by: <balbir@linux.vnet.ibm.com>
---

include/linux/memcontrol.h | 6 ++++++
include/linux/rmap.h | 5 +++--
mm/memcontrol.c | 5 +++++
mm/rmap.c | 30 ++++++++++++++++++++++++------
mm/vmscan.c | 4 ++--
5 files changed, 40 insertions(+), 10 deletions(-)

diff -puN include/linux/rmap.h~mem-control-per-container-page-referenced include/linux/rmap.h
--- linux-2.6.23-rc2-mm2/include/linux/rmap.h~mem-control-per-container-page-referenced 2007-08-17 13:14:20.000000000 +0530
+++ linux-2.6.23-rc2-mm2-balbir/include/linux/rmap.h 2007-08-17 13:14:20.000000000 +0530
@@ -8,6 +8,7 @@
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
+#include <linux/memcontrol.h>

/*
* The anon_vma heads a list of private "related" vmas, to scan if
@@ -86,7 +87,7 @@ static inline void page_dup_rmap(struct
/*
* Called from mm/vmscan.c to handle paging out
*/
-int page_referenced(struct page *, int is_locked);
+int page_referenced(struct page *, int is_locked, struct mem_container *cnt);
int try_to_unmap(struct page *, int ignore_refs);

/*
@@ -114,7 +115,7 @@ int page_mkclean(struct page *);
#define anon_vma_prepare(vma) (0)
#define anon_vma_link(vma) do {} while (0)

-#define page_referenced(page,l) TestClearPageReferenced(page)
+#define page_referenced(page,l,cnt) TestClearPageReferenced(page)
#define try_to_unmap(page, refs) SWAP_FAIL

static inline int page_mkclean(struct page *page)
diff -puN mm/rmap.c~mem-control-per-container-page-referenced mm/rmap.c
--- linux-2.6.23-rc2-mm2/mm/rmap.c~mem-control-per-container-page-referenced 2007-08-17 13:14:20.000000000 +0530
+++ linux-2.6.23-rc2-mm2-balbir/mm/rmap.c 2007-08-17 13:14:20.000000000 +0530
@@ -299,7 +299,8 @@ out:
return referenced;
}

-static int page_referenced_anon(struct page *page)
+static int page_referenced_anon(struct page *page,
+ struct mem_container *mem_cont)
{
unsigned int mapcount;
struct anon_vma *anon_vma;
@@ -312,6 +313,13 @@ static int page_referenced_anon(struct p

mapcount = page_mapcount(page);
list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
+ /*
+ * If we are reclaiming on behalf of a container, skip
+ * counting on behalf of references from different
+ * containers
+ */
+ if (mem_cont && (mm_container(vma->vm_mm) != mem_cont))
+ continue;
referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
@@ -332,7 +340,8 @@ static int page_referenced_anon(struct p
*
* This function is only called from page_referenced for object-based pages.
*/
-static int page_referenced_file(struct page *page)
+static int page_referenced_file(struct page *page,
+ struct mem_container *mem_cont)
{
unsigned int mapcount;
struct address_space *mapping = page->mapping;
@@ -365,6 +374,13 @@ static int page_referenced_file(struct p
mapcount = page_mapcount(page);

vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
+ /*
+ * If we are reclaiming on behalf of a container, skip
+ * counting on behalf of references from different
+ * containers
+ */
+ if (mem_cont && (mm_container(vma->vm_mm) != mem_cont))
+ continue;
if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE))
== (VM_LOCKED|VM_MAYSHARE)) {
referenced++;
@@ -387,7 +403,8 @@ static int page_referenced_file(struct p
* Quick test_and_clear_referenced for all mappings to a page,
* returns the number of ptes which referenced the page.
*/
-int page_referenced(struct page *page, int is_locked)
+int page_referenced(struct page *page, int is_locked,
+ struct mem_container *mem_cont)
{
int referenced = 0;

@@ -399,14 +416,15 @@ int page_referenced(struct page *page, i

if (page_mapped(page) && page->mapping) {
if (PageAnon(page))
- referenced += page_referenced_anon(page);
+ referenced += page_referenced_anon(page, mem_cont);
else if (is_locked)
- referenced += page_referenced_file(page);
+ referenced += page_referenced_file(page, mem_cont);
else if (TestSetPageLocked(page))
referenced++;
else {
if (page->mapping)
- referenced += page_referenced_file(page);
+ referenced +=
+ page_referenced_file(page, mem_cont);
unlock_page(page);
}
}
diff -puN mm/vmscan.c~mem-control-per-container-page-referenced mm/vmscan.c
--- linux-2.6.23-rc2-mm2/mm/vmscan.c~mem-control-per-container-page-referenced 2007-08-17 13:14:20.000000000 +0530
+++ linux-2.6.23-rc2-mm2-balbir/mm/vmscan.c 2007-08-17 13:14:20.000000000 +0530
@@ -511,7 +511,7 @@ static unsigned long shrink_page_list(st
goto keep_locked;
}

- referenced = page_referenced(page, 1);
+ referenced = page_referenced(page, 1, sc->mem_container);
/* In active use or really unfreeable? Activate it. */
if (sc->order <= PAGE_ALLOC_COSTLY_ORDER &&
referenced && page_mapping_inuse(page))
@@ -1065,7 +1065,7 @@ force_reclaim_mapped:
if (page_mapped(page)) {
if (!reclaim_mapped ||
(total_swap_pages == 0 && PageAnon(page)) ||
- page_referenced(page, 0)) {
+ page_referenced(page, 0, sc->mem_container)) {
list_add(&page->lru, &l_active);
continue;
}
diff -puN include/linux/memcontrol.h~mem-control-per-container-page-referenced include/linux/memcontrol.h
--- linux-2.6.23-rc2-mm2/include/linux/memcontrol.h~mem-control-per-container-page-referenced 2007-08-17 13:14:20.000000000 +0530
+++ linux-2.6.23-rc2-mm2-balbir/include/linux/memcontrol.h 2007-08-17 13:14:20.000000000 +0530
@@ -43,6 +43,7 @@ extern unsigned long mem_container_isola
int active);
extern void mem_container_out_of_memory(struct mem_container *mem);
extern int mem_container_cache_charge(struct page *page, struct mm_struct *mm);
+extern struct mem_container *mm_container(struct mm_struct *mm);

static inline void mem_container_uncharge_page(struct page *page)
{
@@ -93,6 +94,11 @@ static inline int mem_container_cache_ch
return 0;
}

+static inline struct mem_container *mm_container(struct mm_struct *mm)
+{
+ return NULL;
+}
+
#endif /* CONFIG_CONTAINER_MEM_CONT */

#endif /* _LINUX_MEMCONTROL_H */
diff -puN mm/memcontrol.c~mem-control-per-container-page-referenced mm/memcontrol.c
--- linux-2.6.23-rc2-mm2/mm/memcontrol.c~mem-control-per-container-page-referenced 2007-08-17 13:14:20.000000000 +0530
+++ linux-2.6.23-rc2-mm2-balbir/mm/memcontrol.c 2007-08-17 13:14:20.000000000 +0530
@@ -109,6 +109,11 @@ struct mem_container *mem_container_from
struct mem_container, css);
}

+inline struct mem_container *mm_container(struct mm_struct *mm)
+{
+ return rcu_dereference(mm->mem_container);
+}
+
void mm_init_container(struct mm_struct *mm, struct task_struct *p)
{
struct mem_container *mem;