[PATCH v3 03/11] memcg: create extensible page stat update routines

Greg Thelen
2010-10-19T00:41:08Z

Replace usage of the mem_cgroup_update_file_mapped() memcg
statistic update routine with two new routines:
* mem_cgroup_inc_page_stat()
* mem_cgroup_dec_page_stat()

As before, only the file_mapped statistic is managed. However,
these more general interfaces allow for new statistics to be
more easily added. New statistics are added with memcg dirty
page accounting.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
---

Changelog since v1:
- Rename (for clarity):
- mem_cgroup_write_page_stat_item -> mem_cgroup_page_stat_item
- mem_cgroup_read_page_stat_item -> mem_cgroup_nr_pages_item

include/linux/memcontrol.h | 31 ++++++++++++++++++++++++++++---
mm/memcontrol.c | 16 +++++++---------
mm/rmap.c | 4 ++--
3 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 159a076..067115c 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -25,6 +25,11 @@ struct page_cgroup;
struct page;
struct mm_struct;

+/* Stats that can be updated by kernel. */
+enum mem_cgroup_page_stat_item {
+ MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
+};
+
extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
struct list_head *dst,
unsigned long *scanned, int order,
@@ -121,7 +126,22 @@ static inline bool mem_cgroup_disabled(void)
return false;
}

-void mem_cgroup_update_file_mapped(struct page *page, int val);
+void mem_cgroup_update_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx,
+ int val);
+
+static inline void mem_cgroup_inc_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx)
+{
+ mem_cgroup_update_page_stat(page, idx, 1);
+}
+
+static inline void mem_cgroup_dec_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx)
+{
+ mem_cgroup_update_page_stat(page, idx, -1);
+}
+
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask);
u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
@@ -293,8 +313,13 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
{
}

-static inline void mem_cgroup_update_file_mapped(struct page *page,
- int val)
+static inline void mem_cgroup_inc_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx)
+{
+}
+
+static inline void mem_cgroup_dec_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx)
{
}

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a4034b6..369879a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1609,7 +1609,8 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
* possibility of race condition. If there is, we take a lock.
*/

-static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
+void mem_cgroup_update_page_stat(struct page *page,
+ enum mem_cgroup_page_stat_item idx, int val)
{
struct mem_cgroup *mem;
struct page_cgroup *pc = lookup_page_cgroup(page);
@@ -1632,30 +1633,27 @@ static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
goto out;
}

- this_cpu_add(mem->stat->count[idx], val);
-
switch (idx) {
- case MEM_CGROUP_STAT_FILE_MAPPED:
+ case MEMCG_NR_FILE_MAPPED:
if (val > 0)
SetPageCgroupFileMapped(pc);
else if (!page_mapped(page))
ClearPageCgroupFileMapped(pc);
+ idx = MEM_CGROUP_STAT_FILE_MAPPED;
break;
default:
BUG();
}

+ this_cpu_add(mem->stat->count[idx], val);
+
out:
if (unlikely(need_unlock))
unlock_page_cgroup(pc);
rcu_read_unlock();
return;
}
-
-void mem_cgroup_update_file_mapped(struct page *page, int val)
-{
- mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
-}
+EXPORT_SYMBOL(mem_cgroup_update_page_stat);

/*
* size of first charge trial. "32" comes from vmscan.c's magic value.
diff --git a/mm/rmap.c b/mm/rmap.c
index 1a8bf76..a66ab76 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -911,7 +911,7 @@ void page_add_file_rmap(struct page *page)
{
if (atomic_inc_and_test(&page->_mapcount)) {
__inc_zone_page_state(page, NR_FILE_MAPPED);
- mem_cgroup_update_file_mapped(page, 1);
+ mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
}
}

@@ -949,7 +949,7 @@ void page_remove_rmap(struct page *page)
__dec_zone_page_state(page, NR_ANON_PAGES);
} else {
__dec_zone_page_state(page, NR_FILE_MAPPED);
- mem_cgroup_update_file_mapped(page, -1);
+ mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
}
/*
* It would be tidy to reset the PageAnon mapping here,
--
1.7.1