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

KAMEZAWA Hiroyuki
2011-07-01T07:18:12Z

On Fri, 1 Jul 2011 10:30:07 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:

> On Fri, 1 Jul 2011 10:16:24 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
>
> > On Thu, 30 Jun 2011 18:06:53 -0700
> > Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > > On Fri, 1 Jul 2011 09:20:59 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> > >
> > > > 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.
> > >
> > > No, it isn't a bug - swappiness also controls the kernel's eagerness to
> > > unmap and reclaim mmapped pagecache.
> > >
> >
> > Oh, really ? I didn't understand that.
> >
> Hmm, anyway, this new version of fix seems better.

Sorry, this seems still buggy. I'll send a new one in the next week :(

Thanks,
-Kame

> ==
> From 7daf93a277e19026bb6edef3e0ac01bbd31dcb5e Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Date: Fri, 1 Jul 2011 10:35:57 +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:
> - move definistions out of CONFIG_SWAP.
> - fixed/tested allyesconfig/allnoconfig compile failure.
> - adjusted signedness to vm_swappiness.
> - drop swappiness from scan_control
> ---
> include/linux/swap.h | 13 +++++++++----
> mm/memcontrol.c | 15 +++++++--------
> mm/vmscan.c | 23 ++++++++++-------------
> 3 files changed, 26 insertions(+), 25 deletions(-)
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index a273468..28f1490 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);
> @@ -299,7 +297,14 @@ static inline void scan_unevictable_unregister_node(struct node *node)
>
> extern int kswapd_run(int nid);
> extern void kswapd_stop(int nid);
> -
> +#ifdef CONFIG_MEM_CGROUP_MEM_RES_CTLR
> +extern int mem_cgroup_swappiness(struct mem_cgroup *mem);
> +#else
> +static inline int mem_cgroup_swappiness(struct mem_cgroup *mem)
> +{
> + return vm_swappiness;
> +}
> +#endif
> #ifdef CONFIG_SWAP
> /* linux/mm/page_io.c */
> extern int swap_readpage(struct page *);
> 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..fb37699 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 +1727,13 @@ 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);
> }
>
> +static int vmscan_swappiness(struct scan_control *sc)
> +{
> + if (scanning_global_lru(sc))
> + return vm_swappiness;
> + return mem_cgroup_swappiness(sc->mem_cgroup);
> +}
> +
> /*
> * 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 +1794,8 @@ 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 +2184,6 @@ 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 +2207,6 @@ 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 +2216,6 @@ 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 +2244,7 @@ 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 +2254,6 @@ 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 +2403,6 @@ 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 +2861,6 @@ 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 +3047,6 @@ 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
>
>
>