[Devel] Re: [PATCH -mmotm 1/2] memcg: dirty pages accounting and limiting infrastructure
KAMEZAWA Hiroyuki
kamezawa.hiroyu at jp.fujitsu.com
Sun Feb 28 17:09:10 PST 2010
On Fri, 26 Feb 2010 23:52:30 +0100
Andrea Righi <arighi at develer.com> wrote:
> Infrastructure to account dirty pages per cgroup and add dirty limit
> interfaces in the cgroupfs:
>
> - Active write-out: memory.dirty_ratio, memory.dirty_bytes
> - Background write-out: memory.dirty_background_ratio, memory.dirty_background_bytes
>
> Signed-off-by: Andrea Righi <arighi at develer.com>
I think nice. but have some nitpicks..
> ---
> include/linux/memcontrol.h | 74 +++++++++-
> mm/memcontrol.c | 354 ++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 399 insertions(+), 29 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 1f9b119..e6af95c 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -25,6 +25,41 @@ struct page_cgroup;
> struct page;
> struct mm_struct;
>
> +/* Cgroup memory statistics items exported to the kernel */
> +enum mem_cgroup_page_stat_item {
> + MEMCG_NR_DIRTYABLE_PAGES,
> + MEMCG_NR_RECLAIM_PAGES,
> + MEMCG_NR_WRITEBACK,
> + MEMCG_NR_DIRTY_WRITEBACK_PAGES,
> +};
> +
> +/*
> + * Statistics for memory cgroup.
> + */
> +enum mem_cgroup_stat_index {
> + /*
> + * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
> + */
> + MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
> + MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
> + MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
> + MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
> + MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
> + MEM_CGROUP_STAT_EVENTS, /* sum of pagein + pageout for internal use */
> + MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
> + MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out.
> + used by soft limit implementation */
> + MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out.
> + used by threshold implementation */
> + MEM_CGROUP_STAT_FILE_DIRTY, /* # of dirty pages in page cache */
> + MEM_CGROUP_STAT_WRITEBACK, /* # of pages under writeback */
> + MEM_CGROUP_STAT_WRITEBACK_TEMP, /* # of pages under writeback using
> + temporary buffers */
> + MEM_CGROUP_STAT_UNSTABLE_NFS, /* # of NFS unstable pages */
> +
> + MEM_CGROUP_STAT_NSTATS,
> +};
> +
> #ifdef CONFIG_CGROUP_MEM_RES_CTLR
> /*
> * All "charge" functions with gfp_mask should use GFP_KERNEL or
> @@ -117,6 +152,13 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
> extern int do_swap_account;
> #endif
>
> +extern long mem_cgroup_dirty_ratio(void);
> +extern unsigned long mem_cgroup_dirty_bytes(void);
> +extern long mem_cgroup_dirty_background_ratio(void);
> +extern unsigned long mem_cgroup_dirty_background_bytes(void);
> +
> +extern s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item);
> +
> static inline bool mem_cgroup_disabled(void)
> {
> if (mem_cgroup_subsys.disabled)
> @@ -125,7 +167,8 @@ static inline bool mem_cgroup_disabled(void)
> }
>
> extern bool mem_cgroup_oom_called(struct task_struct *task);
> -void mem_cgroup_update_file_mapped(struct page *page, int val);
> +void mem_cgroup_update_stat(struct page *page,
> + enum mem_cgroup_stat_index idx, int val);
> unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
> gfp_t gfp_mask, int nid,
> int zid);
> @@ -300,8 +343,8 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
> {
> }
>
> -static inline void mem_cgroup_update_file_mapped(struct page *page,
> - int val)
> +static inline void mem_cgroup_update_stat(struct page *page,
> + enum mem_cgroup_stat_index idx, int val)
> {
> }
>
> @@ -312,6 +355,31 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
> return 0;
> }
>
> +static inline long mem_cgroup_dirty_ratio(void)
> +{
> + return vm_dirty_ratio;
> +}
> +
> +static inline unsigned long mem_cgroup_dirty_bytes(void)
> +{
> + return vm_dirty_bytes;
> +}
> +
> +static inline long mem_cgroup_dirty_background_ratio(void)
> +{
> + return dirty_background_ratio;
> +}
> +
> +static inline unsigned long mem_cgroup_dirty_background_bytes(void)
> +{
> + return dirty_background_bytes;
> +}
> +
> +static inline s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item)
> +{
> + return -ENOMEM;
> +}
> +
> #endif /* CONFIG_CGROUP_MEM_CONT */
>
> #endif /* _LINUX_MEMCONTROL_H */
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index a443c30..56f3204 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -66,31 +66,16 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/
> #define SOFTLIMIT_EVENTS_THRESH (1000)
> #define THRESHOLDS_EVENTS_THRESH (100)
>
> -/*
> - * Statistics for memory cgroup.
> - */
> -enum mem_cgroup_stat_index {
> - /*
> - * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
> - */
> - MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
> - MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
> - MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
> - MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
> - MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
> - MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
> - MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out.
> - used by soft limit implementation */
> - MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out.
> - used by threshold implementation */
> -
> - MEM_CGROUP_STAT_NSTATS,
> -};
> -
> struct mem_cgroup_stat_cpu {
> s64 count[MEM_CGROUP_STAT_NSTATS];
> };
>
> +/* Per cgroup page statistics */
> +struct mem_cgroup_page_stat {
> + enum mem_cgroup_page_stat_item item;
> + s64 value;
> +};
> +
> /*
> * per-zone information in memory controller.
> */
> @@ -205,6 +190,14 @@ struct mem_cgroup {
>
> unsigned int swappiness;
>
> + /* control memory cgroup dirty pages */
> + long dirty_ratio;
> + unsigned long dirty_bytes;
> +
> + /* control background writeback (via writeback threads) */
> + long dirty_background_ratio;
> + unsigned long dirty_background_bytes;
> +
> /* set when res.limit == memsw.limit */
> bool memsw_is_minimum;
>
> @@ -1021,6 +1014,169 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg)
> return swappiness;
> }
>
> +enum mem_cgroup_dirty_param {
> + MEM_CGROUP_DIRTY_RATIO,
> + MEM_CGROUP_DIRTY_BYTES,
> + MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
> + MEM_CGROUP_DIRTY_BACKGROUND_BYTES,
> +};
> +
> +static unsigned long get_dirty_param(struct mem_cgroup *memcg,
> + enum mem_cgroup_dirty_param idx)
> +{
> + unsigned long ret;
> +
> + spin_lock(&memcg->reclaim_param_lock);
do we need lock ?
> + switch (idx) {
> + case MEM_CGROUP_DIRTY_RATIO:
> + ret = memcg->dirty_ratio;
> + break;
> + case MEM_CGROUP_DIRTY_BYTES:
> + ret = memcg->dirty_bytes;
> + break;
> + case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
> + ret = memcg->dirty_background_ratio;
> + break;
> + case MEM_CGROUP_DIRTY_BACKGROUND_BYTES:
> + ret = memcg->dirty_background_bytes;
> + break;
> + default:
> + VM_BUG_ON(1);
> + }
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return ret;
> +}
> +
> +long mem_cgroup_dirty_ratio(void)
> +{
> + struct mem_cgroup *memcg;
> + long ret = vm_dirty_ratio;
> +
> + if (mem_cgroup_disabled())
> + goto out;
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);
please add some excuse comment here. As...
/*
* It's possible that "current" may be moved to other cgroup while
* we access cgroup. But precise check is meaningless because the task
* can be moved after our access and writeback tends to take long time.
* At least, "memcg" will not be freed under rcu_read_lock().
*/
> + if (likely(memcg))
> + ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_RATIO);
> + rcu_read_unlock();
> +out:
> + return ret;
> +}
> +
> +unsigned long mem_cgroup_dirty_bytes(void)
> +{
> + struct mem_cgroup *memcg;
> + unsigned long ret = vm_dirty_bytes;
> +
> + if (mem_cgroup_disabled())
> + goto out;
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);
> + if (likely(memcg))
> + ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BYTES);
> + rcu_read_unlock();
> +out:
> + return ret;
> +}
> +
> +long mem_cgroup_dirty_background_ratio(void)
> +{
> + struct mem_cgroup *memcg;
> + long ret = dirty_background_ratio;
> +
> + if (mem_cgroup_disabled())
> + goto out;
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);
> + if (likely(memcg))
> + ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_RATIO);
> + rcu_read_unlock();
> +out:
> + return ret;
> +}
> +
> +unsigned long mem_cgroup_dirty_background_bytes(void)
> +{
> + struct mem_cgroup *memcg;
> + unsigned long ret = dirty_background_bytes;
> +
> + if (mem_cgroup_disabled())
> + goto out;
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);
> + if (likely(memcg))
> + ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_BYTES);
> + rcu_read_unlock();
> +out:
> + return ret;
> +}
> +
Hmm, how about
memcg->dirty_params[XXXX]
and access by memcg->dirt_params[MEM_CGROUP_DIRTY_BACKGROUND_BYTES]] ?
Then, we don't need to have 4 functsion in the same implementation.
> +static s64 mem_cgroup_get_local_page_stat(struct mem_cgroup *memcg,
> + enum mem_cgroup_page_stat_item item)
> +{
> + s64 ret;
> +
> + switch (item) {
> + case MEMCG_NR_DIRTYABLE_PAGES:
> + ret = res_counter_read_u64(&memcg->res, RES_LIMIT) -
> + res_counter_read_u64(&memcg->res, RES_USAGE);
> + /* Translate free memory in pages */
> + ret >>= PAGE_SHIFT;
> + ret += mem_cgroup_read_stat(memcg, LRU_ACTIVE_ANON) +
> + mem_cgroup_read_stat(memcg, LRU_ACTIVE_FILE) +
> + mem_cgroup_read_stat(memcg, LRU_INACTIVE_ANON) +
> + mem_cgroup_read_stat(memcg, LRU_INACTIVE_FILE);
> + break;
Hmm, is this correct in swapless case ?
> + case MEMCG_NR_RECLAIM_PAGES:
> + ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_DIRTY) +
> + mem_cgroup_read_stat(memcg,
> + MEM_CGROUP_STAT_UNSTABLE_NFS);
> + break;
> + case MEMCG_NR_WRITEBACK:
> + ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
> + break;
> + case MEMCG_NR_DIRTY_WRITEBACK_PAGES:
> + ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK) +
> + mem_cgroup_read_stat(memcg,
> + MEM_CGROUP_STAT_UNSTABLE_NFS);
> + break;
> + default:
> + ret = 0;
> + WARN_ON_ONCE(1);
> + }
> + return ret;
> +}
> +
> +static int mem_cgroup_page_stat_cb(struct mem_cgroup *mem, void *data)
> +{
> + struct mem_cgroup_page_stat *stat = (struct mem_cgroup_page_stat *)data;
> +
> + stat->value += mem_cgroup_get_local_page_stat(mem, stat->item);
> + return 0;
> +}
> +
> +s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item)
> +{
> + struct mem_cgroup_page_stat stat = {};
> + struct mem_cgroup *memcg;
> +
> + rcu_read_lock();
> + memcg = mem_cgroup_from_task(current);
> + if (memcg) {
> + /*
> + * Recursively evaulate page statistics against all cgroup
> + * under hierarchy tree
> + */
> + stat.item = item;
> + mem_cgroup_walk_tree(memcg, &stat, mem_cgroup_page_stat_cb);
> + } else
> + stat.value = -ENOMEM;
> + rcu_read_unlock();
> +
> + return stat.value;
> +}
> +
> static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data)
> {
> int *val = data;
> @@ -1263,10 +1419,10 @@ static void record_last_oom(struct mem_cgroup *mem)
> }
>
> /*
> - * Currently used to update mapped file statistics, but the routine can be
> - * generalized to update other statistics as well.
> + * Generalized routine to update memory cgroup statistics.
> */
> -void mem_cgroup_update_file_mapped(struct page *page, int val)
> +void mem_cgroup_update_stat(struct page *page,
> + enum mem_cgroup_stat_index idx, int val)
> {
> struct mem_cgroup *mem;
> struct page_cgroup *pc;
> @@ -1286,7 +1442,8 @@ void mem_cgroup_update_file_mapped(struct page *page, int val)
> /*
> * Preemption is already disabled. We can use __this_cpu_xxx
> */
> - __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], val);
> + VM_BUG_ON(idx >= MEM_CGROUP_STAT_NSTATS);
> + __this_cpu_add(mem->stat->count[idx], val);
>
> done:
> unlock_page_cgroup(pc);
> @@ -3033,6 +3190,10 @@ enum {
> MCS_PGPGIN,
> MCS_PGPGOUT,
> MCS_SWAP,
> + MCS_FILE_DIRTY,
> + MCS_WRITEBACK,
> + MCS_WRITEBACK_TEMP,
> + MCS_UNSTABLE_NFS,
> MCS_INACTIVE_ANON,
> MCS_ACTIVE_ANON,
> MCS_INACTIVE_FILE,
> @@ -3055,6 +3216,10 @@ struct {
> {"pgpgin", "total_pgpgin"},
> {"pgpgout", "total_pgpgout"},
> {"swap", "total_swap"},
> + {"filedirty", "dirty_pages"},
> + {"writeback", "writeback_pages"},
> + {"writeback_tmp", "writeback_temp_pages"},
> + {"nfs", "nfs_unstable"},
> {"inactive_anon", "total_inactive_anon"},
> {"active_anon", "total_active_anon"},
> {"inactive_file", "total_inactive_file"},
> @@ -3083,6 +3248,14 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data)
> val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT);
> s->stat[MCS_SWAP] += val * PAGE_SIZE;
> }
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_DIRTY);
> + s->stat[MCS_FILE_DIRTY] += val;
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK);
> + s->stat[MCS_WRITEBACK] += val;
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK_TEMP);
> + s->stat[MCS_WRITEBACK_TEMP] += val;
> + val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_UNSTABLE_NFS);
> + s->stat[MCS_UNSTABLE_NFS] += val;
>
> /* per zone stat */
> val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
> @@ -3467,6 +3640,100 @@ unlock:
> return ret;
> }
>
> +static u64 mem_cgroup_dirty_ratio_read(struct cgroup *cgrp, struct cftype *cft)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + return get_dirty_param(memcg, MEM_CGROUP_DIRTY_RATIO);
> +}
> +
> +static int
> +mem_cgroup_dirty_ratio_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + if ((cgrp->parent == NULL) || (val > 100))
> + return -EINVAL;
> +
> + spin_lock(&memcg->reclaim_param_lock);
> + memcg->dirty_ratio = val;
> + memcg->dirty_bytes = 0;
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return 0;
> +}
> +
> +static u64 mem_cgroup_dirty_bytes_read(struct cgroup *cgrp, struct cftype *cft)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + return get_dirty_param(memcg, MEM_CGROUP_DIRTY_BYTES);
> +}
> +
> +static int
> +mem_cgroup_dirty_bytes_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + if (cgrp->parent == NULL)
> + return -EINVAL;
> +
> + spin_lock(&memcg->reclaim_param_lock);
> + memcg->dirty_ratio = 0;
> + memcg->dirty_bytes = val;
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return 0;
> +}
> +
> +static u64
> +mem_cgroup_dirty_background_ratio_read(struct cgroup *cgrp, struct cftype *cft)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + return get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_RATIO);
> +}
> +
> +static int mem_cgroup_dirty_background_ratio_write(struct cgroup *cgrp,
> + struct cftype *cft, u64 val)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + if ((cgrp->parent == NULL) || (val > 100))
> + return -EINVAL;
> +
> + spin_lock(&memcg->reclaim_param_lock);
> + memcg->dirty_background_ratio = val;
> + memcg->dirty_background_bytes = 0;
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return 0;
> +}
> +
> +static u64
> +mem_cgroup_dirty_background_bytes_read(struct cgroup *cgrp, struct cftype *cft)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + return get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_BYTES);
> +}
> +
> +static int mem_cgroup_dirty_background_bytes_write(struct cgroup *cgrp,
> + struct cftype *cft, u64 val)
> +{
> + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
> +
> + if (cgrp->parent == NULL)
> + return -EINVAL;
> +
> + spin_lock(&memcg->reclaim_param_lock);
> + memcg->dirty_background_ratio = 0;
> + memcg->dirty_background_bytes = val;
> + spin_unlock(&memcg->reclaim_param_lock);
> +
> + return 0;
> +}
> +
> static struct cftype mem_cgroup_files[] = {
> {
> .name = "usage_in_bytes",
> @@ -3518,6 +3785,26 @@ static struct cftype mem_cgroup_files[] = {
> .write_u64 = mem_cgroup_swappiness_write,
> },
> {
> + .name = "dirty_ratio",
> + .read_u64 = mem_cgroup_dirty_ratio_read,
> + .write_u64 = mem_cgroup_dirty_ratio_write,
> + },
> + {
> + .name = "dirty_bytes",
> + .read_u64 = mem_cgroup_dirty_bytes_read,
> + .write_u64 = mem_cgroup_dirty_bytes_write,
> + },
> + {
> + .name = "dirty_background_ratio",
> + .read_u64 = mem_cgroup_dirty_background_ratio_read,
> + .write_u64 = mem_cgroup_dirty_background_ratio_write,
> + },
> + {
> + .name = "dirty_background_bytes",
> + .read_u64 = mem_cgroup_dirty_background_bytes_read,
> + .write_u64 = mem_cgroup_dirty_background_bytes_write,
> + },
> + {
> .name = "move_charge_at_immigrate",
> .read_u64 = mem_cgroup_move_charge_read,
> .write_u64 = mem_cgroup_move_charge_write,
> @@ -3776,8 +4063,23 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
> mem->last_scanned_child = 0;
> spin_lock_init(&mem->reclaim_param_lock);
>
> - if (parent)
> + if (parent) {
> mem->swappiness = get_swappiness(parent);
> +
> + mem->dirty_ratio = get_dirty_param(parent,
> + MEM_CGROUP_DIRTY_RATIO);
> + mem->dirty_bytes = get_dirty_param(parent,
> + MEM_CGROUP_DIRTY_BYTES);
> + mem->dirty_background_ratio = get_dirty_param(parent,
> + MEM_CGROUP_DIRTY_BACKGROUND_RATIO);
> + mem->dirty_background_bytes = get_dirty_param(parent,
> + MEM_CGROUP_DIRTY_BACKGROUND_BYTES);
> + } else {
> + mem->dirty_ratio = vm_dirty_ratio;
> + mem->dirty_bytes = vm_dirty_bytes;
> + mem->dirty_background_ratio = vm_dirty_ratio;
> + mem->dirty_background_bytes = vm_dirty_bytes;
background_dirty_ratio ?
Thanks,
-Kame
> + }
> atomic_set(&mem->refcnt, 1);
> mem->move_charge_at_immigrate = 0;
> mutex_init(&mem->thresholds_lock);
> --
> 1.6.3.3
>
>
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