Re: [PATCH] [Cleanup] memcg: export memory cgroup's swappiness v2

KAMEZAWA Hiroyuki
2011-07-01T00:28:06Z

On Fri, 1 Jul 2011 08:50:13 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> On Thu, 30 Jun 2011 13:01:34 -0700
> Andrew Morton <akpm@linux-foundation.org> wrote:

> Ok, I'll check it. Maybe I miss !CONFIG_SWAP...
>

v4 here. Thank you for pointing out. I could think of several ways but
maybe this one is good because using vm_swappines with !CONFIG_SWAP seems
to be a bug.
tested with allyesconfig/allnoconfig.
==
>From 0fb6905c288a16e99ee739f65cb486451e840637 Mon Sep 17 00:00:00 2001
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Date: Wed, 29 Jun 2011 18:24:49 +0900
Subject: [PATCH] export memory cgroup's swappines by mem_cgroup_swappiness()

Each memory cgroup has 'swappiness' value and it can be accessed by
get_swappiness(memcg). The major user is try_to_free_mem_cgroup_pages()
and swappiness is passed by argument. It's propagated by scan_control.

get_swappiness is static function but some planned updates will need to
get swappiness from files other than memcontrol.c
This patch exports get_swappiness() as mem_cgroup_swappiness().
By this, we can remove the argument of swapiness from try_to_free...
and drop swappiness from scan_control. only memcg uses it.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Changelog:
- fixed/tested allyesconfig/allnoconfig compile failure.
- adjusted signedness to vm_swappiness.
- drop swappiness from scan_control
---
include/linux/swap.h | 10 +++++++---
mm/memcontrol.c | 15 +++++++--------
mm/vmscan.c | 33 ++++++++++++++++++++-------------
3 files changed, 34 insertions(+), 24 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index a273468..0299832 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -252,11 +252,9 @@ static inline void lru_cache_add_file(struct page *page)
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask, nodemask_t *mask);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
- gfp_t gfp_mask, bool noswap,
- unsigned int swappiness);
+ gfp_t gfp_mask, bool noswap);
extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
gfp_t gfp_mask, bool noswap,
- unsigned int swappiness,
struct zone *zone,
unsigned long *nr_scanned);
extern int __isolate_lru_page(struct page *page, int mode, int file);
@@ -365,11 +363,17 @@ static inline void put_swap_token(struct mm_struct *mm)
extern void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout);
extern int mem_cgroup_count_swap_user(swp_entry_t ent, struct page **pagep);
+extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
#else
static inline void
mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
{
}
+
+static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
+{
+ return vm_swappiness;
+}
#endif
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern void mem_cgroup_uncharge_swap(swp_entry_t ent);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3e7d5e6..db70176 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -249,7 +249,7 @@ struct mem_cgroup {
atomic_t oom_lock;
atomic_t refcnt;

- unsigned int swappiness;
+ int swappiness;
/* OOM-Killer disable */
int oom_kill_disable;

@@ -1330,7 +1330,7 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *mem)
return margin >> PAGE_SHIFT;
}

-static unsigned int get_swappiness(struct mem_cgroup *memcg)
+int mem_cgroup_swappiness(struct mem_cgroup *memcg)
{
struct cgroup *cgrp = memcg->css.cgroup;

@@ -1776,12 +1776,11 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
/* we use swappiness of local cgroup */
if (check_soft) {
ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
- noswap, get_swappiness(victim), zone,
- &nr_scanned);
+ noswap, zone, &nr_scanned);
*total_scanned += nr_scanned;
} else
ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
- noswap, get_swappiness(victim));
+ noswap);
css_put(&victim->css);
/*
* At shrinking usage, we can't check we should stop here or
@@ -3826,7 +3825,7 @@ try_to_free:
goto out;
}
progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
- false, get_swappiness(mem));
+ false);
if (!progress) {
nr_retries--;
/* maybe some writeback is necessary */
@@ -4288,7 +4287,7 @@ static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
{
struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);

- return get_swappiness(memcg);
+ return mem_cgroup_swappiness(memcg);
}

static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
@@ -4997,7 +4996,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
INIT_LIST_HEAD(&mem->oom_notify);

if (parent)
- mem->swappiness = get_swappiness(parent);
+ mem->swappiness = mem_cgroup_swappiness(parent);
atomic_set(&mem->refcnt, 1);
mem->move_charge_at_immigrate = 0;
mutex_init(&mem->thresholds_lock);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 4f49535..3d1d733 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -95,8 +95,6 @@ struct scan_control {
/* Can pages be swapped as part of reclaim? */
int may_swap;

- int swappiness;
-
int order;

/*
@@ -1729,6 +1727,23 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
return shrink_inactive_list(nr_to_scan, zone, sc, priority, file);
}

+#ifdef CONFIG_SWAP
+static int vmscan_swappiness(struct scan_control *sc)
+{
+ if (scanning_global_lru(sc))
+ return vm_swappiness;
+ return mem_cgroup_swappiness(sc->mem_cgroup);
+}
+#else
+static int vmscan_swappiness(struct scan_control *sc)
+{
+ /* Now, this function is never called with !CONFIG_SWAP */
+ BUG();
+ return 0;
+}
+#endif
+
+
/*
* Determine how aggressively the anon and file LRU lists should be
* scanned. The relative value of each set of LRU lists is determined
@@ -1789,8 +1804,8 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc,
* With swappiness at 100, anonymous and file have the same priority.
* This scanning priority is essentially the inverse of IO cost.
*/
- anon_prio = sc->swappiness;
- file_prio = 200 - sc->swappiness;
+ anon_prio = vmscan_swappiness(sc);
+ file_prio = 200 - vmscan_swappiness(sc);

/*
* OK, so we have swap space and a fair amount of page cache
@@ -2179,7 +2194,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
.nr_to_reclaim = SWAP_CLUSTER_MAX,
.may_unmap = 1,
.may_swap = 1,
- .swappiness = vm_swappiness,
.order = order,
.mem_cgroup = NULL,
.nodemask = nodemask,
@@ -2203,7 +2217,6 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,

unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
gfp_t gfp_mask, bool noswap,
- unsigned int swappiness,
struct zone *zone,
unsigned long *nr_scanned)
{
@@ -2213,7 +2226,6 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
.may_writepage = !laptop_mode,
.may_unmap = 1,
.may_swap = !noswap,
- .swappiness = swappiness,
.order = 0,
.mem_cgroup = mem,
};
@@ -2242,8 +2254,7 @@ unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,

unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
gfp_t gfp_mask,
- bool noswap,
- unsigned int swappiness)
+ bool noswap)
{
struct zonelist *zonelist;
unsigned long nr_reclaimed;
@@ -2253,7 +2264,6 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
.may_unmap = 1,
.may_swap = !noswap,
.nr_to_reclaim = SWAP_CLUSTER_MAX,
- .swappiness = swappiness,
.order = 0,
.mem_cgroup = mem_cont,
.nodemask = NULL, /* we don't care the placement */
@@ -2403,7 +2413,6 @@ static unsigned long balance_pgdat(pg_data_t *pgdat, int order,
* we want to put equal scanning pressure on each zone.
*/
.nr_to_reclaim = ULONG_MAX,
- .swappiness = vm_swappiness,
.order = order,
.mem_cgroup = NULL,
};
@@ -2862,7 +2871,6 @@ unsigned long shrink_all_memory(unsigned long nr_to_reclaim)
.may_writepage = 1,
.nr_to_reclaim = nr_to_reclaim,
.hibernation_mode = 1,
- .swappiness = vm_swappiness,
.order = 0,
};
struct shrink_control shrink = {
@@ -3049,7 +3057,6 @@ static int __zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
.nr_to_reclaim = max_t(unsigned long, nr_pages,
SWAP_CLUSTER_MAX),
.gfp_mask = gfp_mask,
- .swappiness = vm_swappiness,
.order = order,
};
struct shrink_control shrink = {
--
1.7.4.1