Currently, memcg reclaim can disable swap token even if the swap token
mm doesn't belong in its memory cgroup. It's slightly riskly. If an
admin makes very small mem-cgroup and silly guy runs contenious heavy
memory pressure workloa, whole tasks in the system are going to lose
swap-token and then system may become unresponsive. That's bad.
This patch adds 'memcg' parameter into disable_swap_token(). and if
the parameter doesn't match swap-token, VM doesn't put swap-token.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 6 ++++++
include/linux/swap.h | 24 +++++++++++++++++-------
mm/memcontrol.c | 2 +-
mm/thrash.c | 17 +++++++++++++++++
mm/vmscan.c | 4 ++--
5 files changed, 43 insertions(+), 10 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6a0cffd..df572af 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -84,6 +84,7 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem);
extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
+extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
static inline
int mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *cgroup)
@@ -244,6 +245,11 @@ static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
return NULL;
}
+static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
+{
+ return NULL;
+}
+
static inline int mm_match_cgroup(struct mm_struct *mm, struct mem_cgroup *mem)
{
return 1;
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 384eb5f..ccea15d 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -358,21 +358,31 @@ struct backing_dev_info;
extern struct mm_struct *swap_token_mm;
extern void grab_swap_token(struct mm_struct *);
extern void __put_swap_token(struct mm_struct *);
+extern int has_swap_token_memcg(struct mm_struct *mm, struct mem_cgroup *memcg);
-static inline int has_swap_token(struct mm_struct *mm)
+static inline
+int has_swap_token(struct mm_struct *mm)
{
- return (mm == swap_token_mm);
+ return has_swap_token_memcg(mm, NULL);
}
-static inline void put_swap_token(struct mm_struct *mm)
+static inline
+void put_swap_token_memcg(struct mm_struct *mm, struct mem_cgroup *memcg)
{
- if (has_swap_token(mm))
+ if (has_swap_token_memcg(mm, memcg))
__put_swap_token(mm);
}
-static inline void disable_swap_token(void)
+static inline
+void put_swap_token(struct mm_struct *mm)
+{
+ return put_swap_token_memcg(mm, NULL);
+}
+
+static inline
+void disable_swap_token(struct mem_cgroup *memcg)
{
- put_swap_token(swap_token_mm);
+ put_swap_token_memcg(swap_token_mm, memcg);
}
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
@@ -500,7 +510,7 @@ static inline int has_swap_token(struct mm_struct *mm)
return 0;
}
-static inline void disable_swap_token(void)
+static inline void disable_swap_token(struct mem_cgroup *memcg)
{
}
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c2776f1..5683c7a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -735,7 +735,7 @@ struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
struct mem_cgroup, css);
}
-static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
+struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
{
struct mem_cgroup *mem = NULL;
diff --git a/mm/thrash.c b/mm/thrash.c
index 2372d4e..f892a6e 100644
--- a/mm/thrash.c
+++ b/mm/thrash.c
@@ -21,6 +21,7 @@
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/swap.h>
+#include <linux/memcontrol.h>
static DEFINE_SPINLOCK(swap_token_lock);
struct mm_struct *swap_token_mm;
@@ -75,3 +76,19 @@ void __put_swap_token(struct mm_struct *mm)
swap_token_mm = NULL;
spin_unlock(&swap_token_lock);
}
+
+int has_swap_token_memcg(struct mm_struct *mm, struct mem_cgroup *memcg)
+{
+ if (memcg) {
+ struct mem_cgroup *swap_token_memcg;
+
+ /*
+ * memcgroup reclaim can disable swap token only if token task
+ * is in the same cgroup.
+ */
+ swap_token_memcg = try_get_mem_cgroup_from_mm(swap_token_mm);
+ return ((mm == swap_token_mm) && (memcg == swap_token_memcg));
+ } else
+ return (mm == swap_token_mm);
+}
+
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b3a569f..19e179b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2044,7 +2044,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
sc->nr_scanned = 0;
if (!priority)
- disable_swap_token();
+ disable_swap_token(sc->mem_cgroup);
shrink_zones(priority, zonelist, sc);
/*
* Don't shrink slabs when reclaiming memory from
@@ -2353,7 +2353,7 @@ loop_again:
/* The swap token gets in the way of swapout... */
if (!priority)
- disable_swap_token();
+ disable_swap_token(NULL);
all_zones_ok = 1;
balanced = 0;
--
1.7.3.1
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