[PATCH] RSS Container, make page_referenced() container aware

Balbir Singh
2007-04-26T19:03:06Z

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Hi, Pavel,

This patch should help with the shared page issue of one container
holding shared pages in a another container (the container that
brought in the page -- by first touch) hostage.

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

[-- Attachment #2: rss-implement-per-container-page-referenced.patch --]
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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 Singh <balbir@linux.vnet.ibm.com>
---

include/linux/rmap.h | 5 +++--
mm/rmap.c | 26 ++++++++++++++++++++------
mm/vmscan.c | 4 ++--
3 files changed, 25 insertions(+), 10 deletions(-)

diff -puN mm/vmscan.c~rss-implement-per-container-page-referenced mm/vmscan.c
--- linux-2.6.20/mm/vmscan.c~rss-implement-per-container-page-referenced 2007-04-26 23:28:44.000000000 +0530
+++ linux-2.6.20-balbir/mm/vmscan.c 2007-04-27 00:04:38.000000000 +0530
@@ -489,7 +489,7 @@ static unsigned long shrink_page_list(st
if (PageWriteback(page))
goto keep_locked;

- referenced = page_referenced(page, 1);
+ referenced = page_referenced(page, 1, sc->cnt);
/* In active use or really unfreeable? Activate it. */
if (referenced && page_mapping_inuse(page))
goto activate_locked;
@@ -852,7 +852,7 @@ 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->cnt)) {
list_add(&page->lru, &l_active);
continue;
}
diff -puN mm/rmap.c~rss-implement-per-container-page-referenced mm/rmap.c
--- linux-2.6.20/mm/rmap.c~rss-implement-per-container-page-referenced 2007-04-26 23:28:44.000000000 +0530
+++ linux-2.6.20-balbir/mm/rmap.c 2007-04-26 23:33:41.000000000 +0530
@@ -318,7 +318,7 @@ out:
return referenced;
}

-static int page_referenced_anon(struct page *page)
+static int page_referenced_anon(struct page *page, struct rss_container *cnt)
{
unsigned int mapcount;
struct anon_vma *anon_vma;
@@ -331,6 +331,13 @@ 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 (cnt && (vma->vm_mm->rss_container != cnt))
+ continue;
referenced += page_referenced_one(page, vma, &mapcount);
if (!mapcount)
break;
@@ -350,7 +357,7 @@ 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 rss_container *cnt)
{
unsigned int mapcount;
struct address_space *mapping = page->mapping;
@@ -383,6 +390,13 @@ 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 (cnt && (vma->vm_mm->rss_container != cnt))
+ continue;
if ((vma->vm_flags & (VM_LOCKED|VM_MAYSHARE))
== (VM_LOCKED|VM_MAYSHARE)) {
referenced++;
@@ -405,7 +419,7 @@ 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 rss_container *cnt)
{
int referenced = 0;

@@ -417,14 +431,14 @@ 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, cnt);
else if (is_locked)
- referenced += page_referenced_file(page);
+ referenced += page_referenced_file(page, cnt);
else if (TestSetPageLocked(page))
referenced++;
else {
if (page->mapping)
- referenced += page_referenced_file(page);
+ referenced += page_referenced_file(page, cnt);
unlock_page(page);
}
}
diff -puN include/linux/rmap.h~rss-implement-per-container-page-referenced include/linux/rmap.h
--- linux-2.6.20/include/linux/rmap.h~rss-implement-per-container-page-referenced 2007-04-26 23:28:44.000000000 +0530
+++ linux-2.6.20-balbir/include/linux/rmap.h 2007-04-26 23:29:31.000000000 +0530
@@ -8,6 +8,7 @@
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/spinlock.h>
+#include <linux/rss_container.h>

/*
* The anon_vma heads a list of private "related" vmas, to scan if
@@ -93,7 +94,7 @@ 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 rss_container *cnt);
int try_to_unmap(struct page *, int ignore_refs);

/*
@@ -121,7 +122,7 @@ 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)
_