memcg: simple migration handling
Now, management of "charge" under page migration is done under following
manner. (Assume migrate page contents from oldpage to newpage)
before
- "newpage" is charged before migration.
at success.
- "oldpage" is uncharged at somewhere(unmap, radix-tree-replace)
at failure
- "newpage" is uncharged.
- "oldpage" is charged if necessary (*1)
But (*1) is not reliable....because of GFP_ATOMIC.
This patch tries to change behavior as following by charge/commit/cancel ops.
before
- charge PAGE_SIZE (no target page)
success
- commit charge against "newpage".
failure
- commit charge against "oldpage".
(PCG_USED bit works effectively to avoid double-counting)
- if "oldpage" is obsolete, cancel charge of PAGE_SIZE.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index c592f31..b095f5f 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -29,8 +29,6 @@
extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask);
-extern int mem_cgroup_charge_migrate_fixup(struct page *page,
- struct mm_struct *mm, gfp_t gfp_mask);
/* for swap handling */
extern int mem_cgroup_try_charge(struct mm_struct *mm,
gfp_t gfp_mask, struct mem_cgroup **ptr);
@@ -60,8 +58,9 @@
((cgroup) == mem_cgroup_from_task((mm)->owner))
extern int
-mem_cgroup_prepare_migration(struct page *page, struct page *newpage);
-extern void mem_cgroup_end_migration(struct page *page);
+mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr);
+extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
+ struct page *oldpage, struct page *newpage);
/*
* For memory reclaim.
@@ -94,12 +93,6 @@
return 0;
}
-static inline int mem_cgroup_charge_migrate_fixup(struct page *page,
- struct mm_struct *mm, gfp_t gfp_mask)
-{
- return 0;
-}
-
static inline int mem_cgroup_try_charge(struct mm_struct *mm,
gfp_t gfp_mask, struct mem_cgroup **ptr)
{
@@ -144,12 +137,14 @@
}
static inline int
-mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
+mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
{
return 0;
}
-static inline void mem_cgroup_end_migration(struct page *page)
+static inline void mem_cgroup_end_migration(struct mem_cgroup *mem,
+ struct page *oldpage,
+ struct page *newpage)
{
}