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Message-Id: <20081202165130.da859fe1.kamezawa.hiroyu@jp.fujitsu.com>
Date: Tue, 2 Dec 2008 16:51:30 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc: LKML <linux-kernel@...r.kernel.org>, linux-mm <linux-mm@...ck.org>,
Balbir Singh <balbir@...ux.vnet.ibm.com>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH 2/2] memcg: make memory.swappiness file. take2
On Tue, 2 Dec 2008 16:45:09 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com> wrote:
> Currently, /proc/sys/vm/swappiness can change swappiness ratio for global reclaim.
> However, memcg reclaim doesn't have tuning parameter for itself.
>
> In general, the optimal swappiness depend on workload.
> (e.g. hpc workload need to low swappiness than the others.)
>
> Then, per cgroup swappiness improve administrator tunability.
>
>
>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> ---
> Documentation/controllers/memory.txt | 6 ++
> include/linux/swap.h | 3 -
> mm/memcontrol.c | 72 ++++++++++++++++++++++++++++++++---
> mm/vmscan.c | 7 +--
> 4 files changed, 78 insertions(+), 10 deletions(-)
>
> Index: b/mm/memcontrol.c
> ===================================================================
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -161,6 +161,9 @@ struct mem_cgroup {
> unsigned long last_oom_jiffies;
> int obsolete;
> atomic_t refcnt;
> +
> + unsigned int swappiness;
> +
> /*
> * statistics. This must be placed at the end of memcg.
> */
> @@ -586,6 +589,22 @@ done:
> return ret;
> }
>
> +static unsigned int get_swappiness(struct mem_cgroup *memcg)
> +{
> + struct cgroup *cgrp = memcg->css.cgroup;
> + unsigned int swappiness;
> +
> + /* root ? */
> + if (cgrp->parent == NULL)
> + return vm_swappiness;
> +
> + spin_lock(&memcg->reclaim_param_lock);
> + swappiness = memcg->swappiness;
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return swappiness;
> +}
> +
> /*
> * Dance down the hierarchy if needed to reclaim memory. We remember the
> * last child we reclaimed from, so that we don't end up penalizing
> @@ -606,7 +625,8 @@ static int mem_cgroup_hierarchical_recla
> * but there might be left over accounting, even after children
> * have left.
> */
> - ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap);
> + ret = try_to_free_mem_cgroup_pages(root_mem, gfp_mask, noswap,
> + get_swappiness(root_mem));
> if (res_counter_check_under_limit(&root_mem->res))
> return 0;
>
> @@ -620,7 +640,8 @@ static int mem_cgroup_hierarchical_recla
> cgroup_unlock();
> continue;
> }
> - ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap);
> + ret = try_to_free_mem_cgroup_pages(next_mem, gfp_mask, noswap,
> + get_swappiness(next_mem));
> if (res_counter_check_under_limit(&root_mem->res))
> return 0;
> cgroup_lock();
> @@ -1348,7 +1369,8 @@ int mem_cgroup_shrink_usage(struct mm_st
> rcu_read_unlock();
>
> do {
> - progress = try_to_free_mem_cgroup_pages(mem, gfp_mask, true);
> + progress = try_to_free_mem_cgroup_pages(mem, gfp_mask, true,
> + get_swappiness(mem));
> progress += res_counter_check_under_limit(&mem->res);
> } while (!progress && --retry);
>
> @@ -1393,7 +1415,9 @@ static int mem_cgroup_resize_limit(struc
> break;
>
> progress = try_to_free_mem_cgroup_pages(memcg,
> - GFP_HIGHUSER_MOVABLE, false);
> + GFP_HIGHUSER_MOVABLE,
> + false,
> + get_swappiness(memcg));
> if (!progress) retry_count--;
> }
> return ret;
> @@ -1433,7 +1457,8 @@ int mem_cgroup_resize_memsw_limit(struct
> break;
>
> oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
> - try_to_free_mem_cgroup_pages(memcg, GFP_HIGHUSER_MOVABLE, true);
> + try_to_free_mem_cgroup_pages(memcg, GFP_HIGHUSER_MOVABLE, true,
> + get_swappiness(memcg));
> curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
> if (curusage >= oldusage)
> retry_count--;
> @@ -1565,7 +1590,9 @@ try_to_free:
> goto out;
> }
> progress = try_to_free_mem_cgroup_pages(mem,
> - GFP_HIGHUSER_MOVABLE, false);
> + GFP_HIGHUSER_MOVABLE,
> + false,
> + get_swappiness(mem));
> if (!progress) {
> nr_retries--;
> /* maybe some writeback is necessary */
> @@ -1755,6 +1782,31 @@ static int mem_control_stat_show(struct
> return 0;
> }
>
> +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);
> +}
> +
> +static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
> + u64 val)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + if (val > 100)
> + return -EINVAL;
> +
> + if (cgrp->parent == NULL)
> + return -EBUSY;
> +
Hmm, when -EBUSY, it seems this will success in somewher future...
I'll change this to -EINVAL at queuing.
Thanks,
-Kame
> + spin_lock(&memcg->reclaim_param_lock);
> + memcg->swappiness = val;
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return 0;
> +}
> +
>
> static struct cftype mem_cgroup_files[] = {
> {
> @@ -1793,6 +1845,11 @@ static struct cftype mem_cgroup_files[]
> .write_u64 = mem_cgroup_hierarchy_write,
> .read_u64 = mem_cgroup_hierarchy_read,
> },
> + {
> + .name = "swappiness",
> + .read_u64 = mem_cgroup_swappiness_read,
> + .write_u64 = mem_cgroup_swappiness_write,
> + },
> };
>
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
> @@ -1984,6 +2041,9 @@ mem_cgroup_create(struct cgroup_subsys *
> mem->last_scanned_child = NULL;
> spin_lock_init(&mem->reclaim_param_lock);
>
> + if (parent)
> + mem->swappiness = get_swappiness(parent);
> +
> return &mem->css;
> free_out:
> for_each_node_state(node, N_POSSIBLE)
> Index: b/mm/vmscan.c
> ===================================================================
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1716,14 +1716,15 @@ unsigned long try_to_free_pages(struct z
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR
>
> unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
> - gfp_t gfp_mask,
> - bool noswap)
> + gfp_t gfp_mask,
> + bool noswap,
> + unsigned int swappiness)
> {
> struct scan_control sc = {
> .may_writepage = !laptop_mode,
> .may_swap = 1,
> .swap_cluster_max = SWAP_CLUSTER_MAX,
> - .swappiness = vm_swappiness,
> + .swappiness = swappiness,
> .order = 0,
> .mem_cgroup = mem_cont,
> .isolate_pages = mem_cgroup_isolate_pages,
> Index: b/include/linux/swap.h
> ===================================================================
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -214,7 +214,8 @@ static inline void lru_cache_add_active_
> extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
> gfp_t gfp_mask);
> extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
> - gfp_t gfp_mask, bool noswap);
> + gfp_t gfp_mask, bool noswap,
> + unsigned int swappiness);
> extern int __isolate_lru_page(struct page *page, int mode, int file);
> extern unsigned long shrink_all_memory(unsigned long nr_pages);
> extern int vm_swappiness;
> Index: b/Documentation/controllers/memory.txt
> ===================================================================
> --- a/Documentation/controllers/memory.txt
> +++ b/Documentation/controllers/memory.txt
> @@ -289,6 +289,12 @@ will be charged as a new owner of it.
> Because rmdir() moves all pages to parent, some out-of-use page caches can be
> moved to the parent. If you want to avoid that, force_empty will be useful.
>
> +5.2 swappiness
> + Similar to /proc/sys/vm/swappiness, but affecting one group only.
> +
> + The root cgroup can't be changed this parameter.
> + it always use /proc/sys/vm/swappiness internally.
> +
> 6. Hierarchy support
>
> The memory controller supports a deep hierarchy and hierarchical accounting.
>
>
>
--
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