Re: [PATCH v6 2/7] mm/memcg: move reclaim_stat into lruvec

From: Michal Hocko
Date: Mon Mar 26 2012 - 11:16:46 EST

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On Fri 23-03-12 01:56:23, Konstantin Khlebnikov wrote:
> From: Hugh Dickins <hughd@xxxxxxxxxx>
>
> With mem_cgroup_disabled() now explicit, it becomes clear that the
> zone_reclaim_stat structure actually belongs in lruvec, per-zone
> when memcg is disabled but per-memcg per-zone when it's enabled.
>
> We can delete mem_cgroup_get_reclaim_stat(), and change
> update_page_reclaim_stat() to update just the one set of stats,
> the one which get_scan_count() will actually use.
>
> Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

I really like this one. I always hated how we do double accounting.
Happily
Acked-by: Michal Hocko <mhocko@xxxxxxx>

> ---
> include/linux/memcontrol.h | 9 ---------
> include/linux/mmzone.h | 29 ++++++++++++++---------------
> mm/memcontrol.c | 27 +++++++--------------------
> mm/page_alloc.c | 8 ++++----
> mm/swap.c | 14 ++++----------
> mm/vmscan.c | 5 +----
> 6 files changed, 30 insertions(+), 62 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index f94efd2..95dc32c 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -121,8 +121,6 @@ int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg,
> int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
> unsigned long mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg,
> int nid, int zid, unsigned int lrumask);
> -struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
> - struct zone *zone);
> struct zone_reclaim_stat*
> mem_cgroup_get_reclaim_stat_from_page(struct page *page);
> extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
> @@ -351,13 +349,6 @@ mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
> return 0;
> }
>
> -
> -static inline struct zone_reclaim_stat*
> -mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, struct zone *zone)
> -{
> - return NULL;
> -}
> -
> static inline struct zone_reclaim_stat*
> mem_cgroup_get_reclaim_stat_from_page(struct page *page)
> {
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index dff7115..9316931 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -159,8 +159,22 @@ static inline int is_unevictable_lru(enum lru_list lru)
> return (lru == LRU_UNEVICTABLE);
> }
>
> +struct zone_reclaim_stat {
> + /*
> + * The pageout code in vmscan.c keeps track of how many of the
> + * mem/swap backed and file backed pages are refeferenced.
> + * The higher the rotated/scanned ratio, the more valuable
> + * that cache is.
> + *
> + * The anon LRU stats live in [0], file LRU stats in [1]
> + */
> + unsigned long recent_rotated[2];
> + unsigned long recent_scanned[2];
> +};
> +
> struct lruvec {
> struct list_head lists[NR_LRU_LISTS];
> + struct zone_reclaim_stat reclaim_stat;
> };
>
> /* Mask used at gathering information at once (see memcontrol.c) */
> @@ -287,19 +301,6 @@ enum zone_type {
> #error ZONES_SHIFT -- too many zones configured adjust calculation
> #endif
>
> -struct zone_reclaim_stat {
> - /*
> - * The pageout code in vmscan.c keeps track of how many of the
> - * mem/swap backed and file backed pages are refeferenced.
> - * The higher the rotated/scanned ratio, the more valuable
> - * that cache is.
> - *
> - * The anon LRU stats live in [0], file LRU stats in [1]
> - */
> - unsigned long recent_rotated[2];
> - unsigned long recent_scanned[2];
> -};
> -
> struct zone {
> /* Fields commonly accessed by the page allocator */
>
> @@ -374,8 +375,6 @@ struct zone {
> spinlock_t lru_lock;
> struct lruvec lruvec;
>
> - struct zone_reclaim_stat reclaim_stat;
> -
> unsigned long pages_scanned; /* since last reclaim */
> unsigned long flags; /* zone flags, see below */
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index b2ee6df..59697fb 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -138,7 +138,6 @@ struct mem_cgroup_per_zone {
>
> struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
>
> - struct zone_reclaim_stat reclaim_stat;
> struct rb_node tree_node; /* RB tree node */
> unsigned long long usage_in_excess;/* Set to the value by which */
> /* the soft limit is exceeded*/
> @@ -1233,16 +1232,6 @@ int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)
> return (active > inactive);
> }
>
> -struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
> - struct zone *zone)
> -{
> - int nid = zone_to_nid(zone);
> - int zid = zone_idx(zone);
> - struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid);
> -
> - return &mz->reclaim_stat;
> -}
> -
> struct zone_reclaim_stat *
> mem_cgroup_get_reclaim_stat_from_page(struct page *page)
> {
> @@ -1258,7 +1247,7 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
> /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */
> smp_rmb();
> mz = page_cgroup_zoneinfo(pc->mem_cgroup, page);
> - return &mz->reclaim_stat;
> + return &mz->lruvec.reclaim_stat;
> }
>
> #define mem_cgroup_from_res_counter(counter, member) \
> @@ -4216,21 +4205,19 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
> {
> int nid, zid;
> struct mem_cgroup_per_zone *mz;
> + struct zone_reclaim_stat *rstat;
> unsigned long recent_rotated[2] = {0, 0};
> unsigned long recent_scanned[2] = {0, 0};
>
> for_each_online_node(nid)
> for (zid = 0; zid < MAX_NR_ZONES; zid++) {
> mz = mem_cgroup_zoneinfo(memcg, nid, zid);
> + rstat = &mz->lruvec.reclaim_stat;
>
> - recent_rotated[0] +=
> - mz->reclaim_stat.recent_rotated[0];
> - recent_rotated[1] +=
> - mz->reclaim_stat.recent_rotated[1];
> - recent_scanned[0] +=
> - mz->reclaim_stat.recent_scanned[0];
> - recent_scanned[1] +=
> - mz->reclaim_stat.recent_scanned[1];
> + recent_rotated[0] += rstat->recent_rotated[0];
> + recent_rotated[1] += rstat->recent_rotated[1];
> + recent_scanned[0] += rstat->recent_scanned[0];
> + recent_scanned[1] += rstat->recent_scanned[1];
> }
> cb->fill(cb, "recent_rotated_anon", recent_rotated[0]);
> cb->fill(cb, "recent_rotated_file", recent_rotated[1]);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index caea788..95ac749 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4317,10 +4317,10 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
> zone_pcp_init(zone);
> for_each_lru(lru)
> INIT_LIST_HEAD(&zone->lruvec.lists[lru]);
> - zone->reclaim_stat.recent_rotated[0] = 0;
> - zone->reclaim_stat.recent_rotated[1] = 0;
> - zone->reclaim_stat.recent_scanned[0] = 0;
> - zone->reclaim_stat.recent_scanned[1] = 0;
> + zone->lruvec.reclaim_stat.recent_rotated[0] = 0;
> + zone->lruvec.reclaim_stat.recent_rotated[1] = 0;
> + zone->lruvec.reclaim_stat.recent_scanned[0] = 0;
> + zone->lruvec.reclaim_stat.recent_scanned[1] = 0;
> zap_zone_vm_stats(zone);
> zone->flags = 0;
> if (!size)
> diff --git a/mm/swap.c b/mm/swap.c
> index 5c13f13..60d14da 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -279,21 +279,15 @@ void rotate_reclaimable_page(struct page *page)
> static void update_page_reclaim_stat(struct zone *zone, struct page *page,
> int file, int rotated)
> {
> - struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat;
> - struct zone_reclaim_stat *memcg_reclaim_stat;
> + struct zone_reclaim_stat *reclaim_stat;
>
> - memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page);
> + reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page);
> + if (!reclaim_stat)
> + reclaim_stat = &zone->lruvec.reclaim_stat;
>
> reclaim_stat->recent_scanned[file]++;
> if (rotated)
> reclaim_stat->recent_rotated[file]++;
> -
> - if (!memcg_reclaim_stat)
> - return;
> -
> - memcg_reclaim_stat->recent_scanned[file]++;
> - if (rotated)
> - memcg_reclaim_stat->recent_rotated[file]++;
> }
>
> static void __activate_page(struct page *page, void *arg)
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index c684f44..f4dca0c 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -173,10 +173,7 @@ static bool global_reclaim(struct scan_control *sc)
>
> static struct zone_reclaim_stat *get_reclaim_stat(struct mem_cgroup_zone *mz)
> {
> - if (!mem_cgroup_disabled())
> - return mem_cgroup_get_reclaim_stat(mz->mem_cgroup, mz->zone);
> -
> - return &mz->zone->reclaim_stat;
> + return &mem_cgroup_zone_lruvec(mz->zone, mz->mem_cgroup)->reclaim_stat;
> }
>
> static unsigned long zone_nr_lru_pages(struct mem_cgroup_zone *mz,
>
> --
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--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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