vmscan,memcg: memcg aware swap token
Currently, memcg reclaim can disable swap token even if the swap token mm
doesn't belong in its memory cgroup. It's slightly risky. If an admin
creates very small mem-cgroup and silly guy runs contentious heavy memory
pressure workload, every tasks 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 disable it.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel<riel@redhat.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 9724a38..50940da 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -84,6 +84,7 @@
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)
@@ -246,6 +247,11 @@
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..e705646 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -358,6 +358,7 @@
extern struct mm_struct *swap_token_mm;
extern void grab_swap_token(struct mm_struct *);
extern void __put_swap_token(struct mm_struct *);
+extern void disable_swap_token(struct mem_cgroup *memcg);
static inline int has_swap_token(struct mm_struct *mm)
{
@@ -370,11 +371,6 @@
__put_swap_token(mm);
}
-static inline void disable_swap_token(void)
-{
- put_swap_token(swap_token_mm);
-}
-
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
extern void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
@@ -500,7 +496,7 @@
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 bd9052a..e37c44d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -735,7 +735,7 @@
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;
@@ -5414,18 +5414,16 @@
struct cgroup *old_cont,
struct task_struct *p)
{
- struct mm_struct *mm;
+ struct mm_struct *mm = get_task_mm(p);
- if (!mc.to)
- /* no need to move charge */
- return;
-
- mm = get_task_mm(p);
if (mm) {
- mem_cgroup_move_charge(mm);
+ if (mc.to)
+ mem_cgroup_move_charge(mm);
+ put_swap_token(mm);
mmput(mm);
}
- mem_cgroup_clear_mc();
+ if (mc.to)
+ mem_cgroup_clear_mc();
}
#else /* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
diff --git a/mm/thrash.c b/mm/thrash.c
index 2372d4e..6cdf865 100644
--- a/mm/thrash.c
+++ b/mm/thrash.c
@@ -21,11 +21,31 @@
#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;
+struct mem_cgroup *swap_token_memcg;
static unsigned int global_faults;
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+static struct mem_cgroup *swap_token_memcg_from_mm(struct mm_struct *mm)
+{
+ struct mem_cgroup *memcg;
+
+ memcg = try_get_mem_cgroup_from_mm(mm);
+ if (memcg)
+ css_put(mem_cgroup_css(memcg));
+
+ return memcg;
+}
+#else
+static struct mem_cgroup *swap_token_memcg_from_mm(struct mm_struct *mm)
+{
+ return NULL;
+}
+#endif
+
void grab_swap_token(struct mm_struct *mm)
{
int current_interval;
@@ -38,40 +58,69 @@
return;
/* First come first served */
- if (swap_token_mm == NULL) {
- mm->token_priority = mm->token_priority + 2;
- swap_token_mm = mm;
+ if (!swap_token_mm)
+ goto replace_token;
+
+ if (mm == swap_token_mm) {
+ mm->token_priority += 2;
goto out;
}
- if (mm != swap_token_mm) {
- if (current_interval < mm->last_interval)
- mm->token_priority++;
- else {
- if (likely(mm->token_priority > 0))
- mm->token_priority--;
- }
- /* Check if we deserve the token */
- if (mm->token_priority > swap_token_mm->token_priority) {
- mm->token_priority += 2;
- swap_token_mm = mm;
- }
- } else {
- /* Token holder came in again! */
- mm->token_priority += 2;
+ if (current_interval < mm->last_interval)
+ mm->token_priority++;
+ else {
+ if (likely(mm->token_priority > 0))
+ mm->token_priority--;
}
+ /* Check if we deserve the token */
+ if (mm->token_priority > swap_token_mm->token_priority)
+ goto replace_token;
+
out:
mm->faultstamp = global_faults;
mm->last_interval = current_interval;
spin_unlock(&swap_token_lock);
+ return;
+
+replace_token:
+ mm->token_priority += 2;
+ swap_token_mm = mm;
+ swap_token_memcg = swap_token_memcg_from_mm(mm);
+ goto out;
}
/* Called on process exit. */
void __put_swap_token(struct mm_struct *mm)
{
spin_lock(&swap_token_lock);
- if (likely(mm == swap_token_mm))
+ if (likely(mm == swap_token_mm)) {
swap_token_mm = NULL;
+ swap_token_memcg = NULL;
+ }
spin_unlock(&swap_token_lock);
}
+
+static bool match_memcg(struct mem_cgroup *a, struct mem_cgroup *b)
+{
+ if (!a)
+ return true;
+ if (!b)
+ return true;
+ if (a == b)
+ return true;
+ return false;
+}
+
+void disable_swap_token(struct mem_cgroup *memcg)
+{
+ /* memcg reclaim don't disable unrelated mm token. */
+ if (match_memcg(memcg, swap_token_memcg)) {
+ spin_lock(&swap_token_lock);
+ if (match_memcg(memcg, swap_token_memcg)) {
+ swap_token_mm = NULL;
+ swap_token_memcg = NULL;
+ }
+ spin_unlock(&swap_token_lock);
+ }
+}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index faa0a08..dbe6ea3 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2081,7 +2081,7 @@
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
sc->nr_scanned = 0;
if (!priority)
- disable_swap_token();
+ disable_swap_token(sc->mem_cgroup);
total_scanned += shrink_zones(priority, zonelist, sc);
/*
* Don't shrink slabs when reclaiming memory from
@@ -2407,7 +2407,7 @@
/* The swap token gets in the way of swapout... */
if (!priority)
- disable_swap_token();
+ disable_swap_token(NULL);
all_zones_ok = 1;
balanced = 0;