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

[Balbir Singh]

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@xxxxxxxxxxxxxxxxxx>
---

 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;
_

-- 
	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL
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