Re: [PATCH 03/31] mm, vmscan: move LRU lists to node
From: Minchan Kim
Date: Mon Jul 04 2016 - 21:21:03 EST
On Fri, Jul 01, 2016 at 09:01:11PM +0100, Mel Gorman wrote:
> This moves the LRU lists from the zone to the node and related data such
> as counters, tracing, congestion tracking and writeback tracking.
> Unfortunately, due to reclaim and compaction retry logic, it is necessary
> to account for the number of LRU pages on both zone and node logic. Most
> reclaim logic is based on the node counters but the retry logic uses the
> zone counters which do not distinguish inactive and inactive sizes. It
active
> would be possible to leave the LRU counters on a per-zone basis but it's a
> heavier calculation across multiple cache lines that is much more frequent
> than the retry checks.
>
> Other than the LRU counters, this is mostly a mechanical patch but note
> that it introduces a number of anomalies. For example, the scans are
> per-zone but using per-node counters. We also mark a node as congested
> when a zone is congested. This causes weird problems that are fixed later
> but is easier to review.
>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> arch/tile/mm/pgtable.c | 8 +-
> drivers/base/node.c | 19 +--
> drivers/staging/android/lowmemorykiller.c | 8 +-
> include/linux/backing-dev.h | 2 +-
> include/linux/memcontrol.h | 16 +--
> include/linux/mm_inline.h | 21 ++-
> include/linux/mmzone.h | 69 +++++----
> include/linux/swap.h | 1 +
> include/linux/vm_event_item.h | 10 +-
> include/linux/vmstat.h | 17 +++
> include/trace/events/vmscan.h | 12 +-
> kernel/power/snapshot.c | 10 +-
> mm/backing-dev.c | 15 +-
> mm/compaction.c | 18 +--
> mm/huge_memory.c | 2 +-
> mm/internal.h | 2 +-
> mm/khugepaged.c | 4 +-
> mm/memcontrol.c | 17 +--
> mm/memory-failure.c | 4 +-
> mm/memory_hotplug.c | 2 +-
> mm/mempolicy.c | 2 +-
> mm/migrate.c | 21 +--
> mm/mlock.c | 2 +-
> mm/page-writeback.c | 8 +-
> mm/page_alloc.c | 70 ++++-----
> mm/swap.c | 50 +++----
> mm/vmscan.c | 226 +++++++++++++++++-------------
> mm/vmstat.c | 47 ++++---
> mm/workingset.c | 4 +-
> 29 files changed, 387 insertions(+), 300 deletions(-)
>
> diff --git a/arch/tile/mm/pgtable.c b/arch/tile/mm/pgtable.c
> index c4d5bf841a7f..9e389213580d 100644
> --- a/arch/tile/mm/pgtable.c
> +++ b/arch/tile/mm/pgtable.c
> @@ -45,10 +45,10 @@ void show_mem(unsigned int filter)
> struct zone *zone;
>
> pr_err("Active:%lu inactive:%lu dirty:%lu writeback:%lu unstable:%lu free:%lu\n slab:%lu mapped:%lu pagetables:%lu bounce:%lu pagecache:%lu swap:%lu\n",
> - (global_page_state(NR_ACTIVE_ANON) +
> - global_page_state(NR_ACTIVE_FILE)),
> - (global_page_state(NR_INACTIVE_ANON) +
> - global_page_state(NR_INACTIVE_FILE)),
> + (global_node_page_state(NR_ACTIVE_ANON) +
> + global_node_page_state(NR_ACTIVE_FILE)),
> + (global_node_page_state(NR_INACTIVE_ANON) +
> + global_node_page_state(NR_INACTIVE_FILE)),
> global_page_state(NR_FILE_DIRTY),
> global_page_state(NR_WRITEBACK),
> global_page_state(NR_UNSTABLE_NFS),
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 92d8e090c5b3..b7f01a4a642d 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -56,6 +56,7 @@ static ssize_t node_read_meminfo(struct device *dev,
> {
> int n;
> int nid = dev->id;
> + struct pglist_data *pgdat = NODE_DATA(nid);
> struct sysinfo i;
>
> si_meminfo_node(&i, nid);
> @@ -74,15 +75,15 @@ static ssize_t node_read_meminfo(struct device *dev,
> nid, K(i.totalram),
> nid, K(i.freeram),
> nid, K(i.totalram - i.freeram),
> - nid, K(sum_zone_node_page_state(nid, NR_ACTIVE_ANON) +
> - sum_zone_node_page_state(nid, NR_ACTIVE_FILE)),
> - nid, K(sum_zone_node_page_state(nid, NR_INACTIVE_ANON) +
> - sum_zone_node_page_state(nid, NR_INACTIVE_FILE)),
> - nid, K(sum_zone_node_page_state(nid, NR_ACTIVE_ANON)),
> - nid, K(sum_zone_node_page_state(nid, NR_INACTIVE_ANON)),
> - nid, K(sum_zone_node_page_state(nid, NR_ACTIVE_FILE)),
> - nid, K(sum_zone_node_page_state(nid, NR_INACTIVE_FILE)),
> - nid, K(sum_zone_node_page_state(nid, NR_UNEVICTABLE)),
> + nid, K(node_page_state(pgdat, NR_ACTIVE_ANON) +
> + node_page_state(pgdat, NR_ACTIVE_FILE)),
> + nid, K(node_page_state(pgdat, NR_INACTIVE_ANON) +
> + node_page_state(pgdat, NR_INACTIVE_FILE)),
> + nid, K(node_page_state(pgdat, NR_ACTIVE_ANON)),
> + nid, K(node_page_state(pgdat, NR_INACTIVE_ANON)),
> + nid, K(node_page_state(pgdat, NR_ACTIVE_FILE)),
> + nid, K(node_page_state(pgdat, NR_INACTIVE_FILE)),
> + nid, K(node_page_state(pgdat, NR_UNEVICTABLE)),
> nid, K(sum_zone_node_page_state(nid, NR_MLOCK)));
>
> #ifdef CONFIG_HIGHMEM
> diff --git a/drivers/staging/android/lowmemorykiller.c b/drivers/staging/android/lowmemorykiller.c
> index 24d2745e9437..93dbcc38eb0f 100644
> --- a/drivers/staging/android/lowmemorykiller.c
> +++ b/drivers/staging/android/lowmemorykiller.c
> @@ -72,10 +72,10 @@ static unsigned long lowmem_deathpending_timeout;
> static unsigned long lowmem_count(struct shrinker *s,
> struct shrink_control *sc)
> {
> - return global_page_state(NR_ACTIVE_ANON) +
> - global_page_state(NR_ACTIVE_FILE) +
> - global_page_state(NR_INACTIVE_ANON) +
> - global_page_state(NR_INACTIVE_FILE);
> + return global_node_page_state(NR_ACTIVE_ANON) +
> + global_node_page_state(NR_ACTIVE_FILE) +
> + global_node_page_state(NR_INACTIVE_ANON) +
> + global_node_page_state(NR_INACTIVE_FILE);
> }
>
> static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
> diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
> index c82794f20110..491a91717788 100644
> --- a/include/linux/backing-dev.h
> +++ b/include/linux/backing-dev.h
> @@ -197,7 +197,7 @@ static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
> }
>
> long congestion_wait(int sync, long timeout);
> -long wait_iff_congested(struct zone *zone, int sync, long timeout);
> +long wait_iff_congested(struct pglist_data *pgdat, int sync, long timeout);
> int pdflush_proc_obsolete(struct ctl_table *table, int write,
> void __user *buffer, size_t *lenp, loff_t *ppos);
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 104efa6874db..1927dcb6921e 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -340,7 +340,7 @@ static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
> struct lruvec *lruvec;
>
> if (mem_cgroup_disabled()) {
> - lruvec = &zone->lruvec;
> + lruvec = zone_lruvec(zone);
> goto out;
> }
>
> @@ -352,12 +352,12 @@ static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
> * we have to be prepared to initialize lruvec->zone here;
lruvec->pgdat
> * and if offlined then reonlined, we need to reinitialize it.
> */
> - if (unlikely(lruvec->zone != zone))
> - lruvec->zone = zone;
> + if (unlikely(lruvec->pgdat != zone->zone_pgdat))
> + lruvec->pgdat = zone->zone_pgdat;
> return lruvec;
> }
>
> -struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
> +struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
>
> bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
> struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
> @@ -438,7 +438,7 @@ static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
> int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
>
> void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
> - int nr_pages);
> + enum zone_type zid, int nr_pages);
>
> unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
> int nid, unsigned int lru_mask);
> @@ -613,13 +613,13 @@ static inline void mem_cgroup_migrate(struct page *old, struct page *new)
> static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
> struct mem_cgroup *memcg)
> {
> - return &zone->lruvec;
> + return zone_lruvec(zone);
> }
>
> static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
> - struct zone *zone)
> + struct pglist_data *pgdat)
> {
> - return &zone->lruvec;
> + return &pgdat->lruvec;
> }
>
> static inline bool mm_match_cgroup(struct mm_struct *mm,
> diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
> index 5bd29ba4f174..9aadcc781857 100644
> --- a/include/linux/mm_inline.h
> +++ b/include/linux/mm_inline.h
> @@ -23,25 +23,32 @@ static inline int page_is_file_cache(struct page *page)
> }
>
> static __always_inline void __update_lru_size(struct lruvec *lruvec,
> - enum lru_list lru, int nr_pages)
> + enum lru_list lru, enum zone_type zid,
> + int nr_pages)
> {
> - __mod_zone_page_state(lruvec_zone(lruvec), NR_LRU_BASE + lru, nr_pages);
> + struct pglist_data *pgdat = lruvec_pgdat(lruvec);
> +
> + __mod_node_page_state(pgdat, NR_LRU_BASE + lru, nr_pages);
> + __mod_zone_page_state(&pgdat->node_zones[zid],
> + NR_ZONE_LRU_BASE + !!is_file_lru(lru),
> + nr_pages);
> }
>
> static __always_inline void update_lru_size(struct lruvec *lruvec,
> - enum lru_list lru, int nr_pages)
> + enum lru_list lru, enum zone_type zid,
> + int nr_pages)
> {
> #ifdef CONFIG_MEMCG
> - mem_cgroup_update_lru_size(lruvec, lru, nr_pages);
> + mem_cgroup_update_lru_size(lruvec, lru, zid, nr_pages);
> #else
> - __update_lru_size(lruvec, lru, nr_pages);
> + __update_lru_size(lruvec, lru, zid, nr_pages);
> #endif
> }
>
> static __always_inline void add_page_to_lru_list(struct page *page,
> struct lruvec *lruvec, enum lru_list lru)
> {
> - update_lru_size(lruvec, lru, hpage_nr_pages(page));
> + update_lru_size(lruvec, lru, page_zonenum(page), hpage_nr_pages(page));
> list_add(&page->lru, &lruvec->lists[lru]);
> }
>
> @@ -49,7 +56,7 @@ static __always_inline void del_page_from_lru_list(struct page *page,
> struct lruvec *lruvec, enum lru_list lru)
> {
> list_del(&page->lru);
> - update_lru_size(lruvec, lru, -hpage_nr_pages(page));
> + update_lru_size(lruvec, lru, page_zonenum(page), -hpage_nr_pages(page));
> }
>
> /**
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 2d5087e3c034..258c20758e80 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -111,12 +111,9 @@ enum zone_stat_item {
> /* First 128 byte cacheline (assuming 64 bit words) */
> NR_FREE_PAGES,
> NR_ALLOC_BATCH,
> - NR_LRU_BASE,
> - NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
> - NR_ACTIVE_ANON, /* " " " " " */
> - NR_INACTIVE_FILE, /* " " " " " */
> - NR_ACTIVE_FILE, /* " " " " " */
> - NR_UNEVICTABLE, /* " " " " " */
> + NR_ZONE_LRU_BASE, /* Used only for compaction and reclaim retry */
> + NR_ZONE_LRU_ANON = NR_ZONE_LRU_BASE,
> + NR_ZONE_LRU_FILE,
> NR_MLOCK, /* mlock()ed pages found and moved off LRU */
> NR_ANON_PAGES, /* Mapped anonymous pages */
> NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
> @@ -134,12 +131,9 @@ enum zone_stat_item {
> NR_VMSCAN_WRITE,
> NR_VMSCAN_IMMEDIATE, /* Prioritise for reclaim when writeback ends */
> NR_WRITEBACK_TEMP, /* Writeback using temporary buffers */
> - NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
> - NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
> NR_SHMEM, /* shmem pages (included tmpfs/GEM pages) */
> NR_DIRTIED, /* page dirtyings since bootup */
> NR_WRITTEN, /* page writings since bootup */
> - NR_PAGES_SCANNED, /* pages scanned since last reclaim */
> #if IS_ENABLED(CONFIG_ZSMALLOC)
> NR_ZSPAGES, /* allocated in zsmalloc */
> #endif
> @@ -161,6 +155,15 @@ enum zone_stat_item {
> NR_VM_ZONE_STAT_ITEMS };
>
> enum node_stat_item {
> + NR_LRU_BASE,
> + NR_INACTIVE_ANON = NR_LRU_BASE, /* must match order of LRU_[IN]ACTIVE */
> + NR_ACTIVE_ANON, /* " " " " " */
> + NR_INACTIVE_FILE, /* " " " " " */
> + NR_ACTIVE_FILE, /* " " " " " */
> + NR_UNEVICTABLE, /* " " " " " */
> + NR_ISOLATED_ANON, /* Temporary isolated pages from anon lru */
> + NR_ISOLATED_FILE, /* Temporary isolated pages from file lru */
> + NR_PAGES_SCANNED, /* pages scanned since last reclaim */
> NR_VM_NODE_STAT_ITEMS
> };
>
> @@ -219,7 +222,7 @@ struct lruvec {
> /* Evictions & activations on the inactive file list */
> atomic_long_t inactive_age;
> #ifdef CONFIG_MEMCG
> - struct zone *zone;
> + struct pglist_data *pgdat;
> #endif
> };
>
> @@ -357,13 +360,6 @@ struct zone {
> #ifdef CONFIG_NUMA
> int node;
> #endif
> -
> - /*
> - * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
> - * this zone's LRU. Maintained by the pageout code.
> - */
> - unsigned int inactive_ratio;
> -
> struct pglist_data *zone_pgdat;
> struct per_cpu_pageset __percpu *pageset;
>
> @@ -495,9 +491,6 @@ struct zone {
>
> /* Write-intensive fields used by page reclaim */
trivial:
We moved lru_lock and lruvec to pgdat so I'm not sure we need ZONE_PADDING,
still.
>
> - /* Fields commonly accessed by the page reclaim scanner */
> - struct lruvec lruvec;
> -
> /*
> * When free pages are below this point, additional steps are taken
> * when reading the number of free pages to avoid per-cpu counter
> @@ -537,17 +530,20 @@ struct zone {
>
> enum zone_flags {
> ZONE_RECLAIM_LOCKED, /* prevents concurrent reclaim */
> - ZONE_CONGESTED, /* zone has many dirty pages backed by
> + ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
> +};
> +
> +enum pgdat_flags {
> + PGDAT_CONGESTED, /* zone has many dirty pages backed by
node or pgdat, whatever.
> * a congested BDI
> */
> - ZONE_DIRTY, /* reclaim scanning has recently found
> + PGDAT_DIRTY, /* reclaim scanning has recently found
> * many dirty file pages at the tail
> * of the LRU.
> */
> - ZONE_WRITEBACK, /* reclaim scanning has recently found
> + PGDAT_WRITEBACK, /* reclaim scanning has recently found
> * many pages under writeback
> */
> - ZONE_FAIR_DEPLETED, /* fair zone policy batch depleted */
> };
>
> static inline unsigned long zone_end_pfn(const struct zone *zone)
> @@ -701,12 +697,26 @@ typedef struct pglist_data {
> unsigned long first_deferred_pfn;
> #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
>
> +
Unnecessary change.
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> spinlock_t split_queue_lock;
> struct list_head split_queue;
> unsigned long split_queue_len;
> #endif
>
> + /* Fields commonly accessed by the page reclaim scanner */
> + struct lruvec lruvec;
> +
> + /*
> + * The target ratio of ACTIVE_ANON to INACTIVE_ANON pages on
> + * this node's LRU. Maintained by the pageout code.
> + */
> + unsigned int inactive_ratio;
> +
> + unsigned long flags;
> +
> + ZONE_PADDING(_pad2_)
> +
> /* Per-node vmstats */
> struct per_cpu_nodestat __percpu *per_cpu_nodestats;
> atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
> @@ -728,6 +738,11 @@ static inline spinlock_t *zone_lru_lock(struct zone *zone)
> return &zone->zone_pgdat->lru_lock;
> }
>
> +static inline struct lruvec *zone_lruvec(struct zone *zone)
> +{
> + return &zone->zone_pgdat->lruvec;
> +}
> +
> static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat)
> {
> return pgdat->node_start_pfn + pgdat->node_spanned_pages;
> @@ -779,12 +794,12 @@ extern int init_currently_empty_zone(struct zone *zone, unsigned long start_pfn,
>
> extern void lruvec_init(struct lruvec *lruvec);
>
> -static inline struct zone *lruvec_zone(struct lruvec *lruvec)
> +static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec)
> {
> #ifdef CONFIG_MEMCG
> - return lruvec->zone;
> + return lruvec->pgdat;
> #else
> - return container_of(lruvec, struct zone, lruvec);
> + return container_of(lruvec, struct pglist_data, lruvec);
> #endif
> }
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 0af2bb2028fd..c82f916008b7 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -317,6 +317,7 @@ extern void lru_cache_add_active_or_unevictable(struct page *page,
>
> /* linux/mm/vmscan.c */
> extern unsigned long zone_reclaimable_pages(struct zone *zone);
> +extern unsigned long pgdat_reclaimable_pages(struct pglist_data *pgdat);
> extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
> gfp_t gfp_mask, nodemask_t *mask);
> extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
> diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
> index 42604173f122..1798ff542517 100644
> --- a/include/linux/vm_event_item.h
> +++ b/include/linux/vm_event_item.h
> @@ -26,11 +26,11 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
> PGFREE, PGACTIVATE, PGDEACTIVATE,
> PGFAULT, PGMAJFAULT,
> PGLAZYFREED,
> - FOR_ALL_ZONES(PGREFILL),
> - FOR_ALL_ZONES(PGSTEAL_KSWAPD),
> - FOR_ALL_ZONES(PGSTEAL_DIRECT),
> - FOR_ALL_ZONES(PGSCAN_KSWAPD),
> - FOR_ALL_ZONES(PGSCAN_DIRECT),
> + PGREFILL,
> + PGSTEAL_KSWAPD,
> + PGSTEAL_DIRECT,
> + PGSCAN_KSWAPD,
> + PGSCAN_DIRECT,
> PGSCAN_DIRECT_THROTTLE,
> #ifdef CONFIG_NUMA
> PGSCAN_ZONE_RECLAIM_FAILED,
> diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
> index d1744aa3ab9c..ced0c3e9da88 100644
> --- a/include/linux/vmstat.h
> +++ b/include/linux/vmstat.h
> @@ -178,6 +178,23 @@ static inline unsigned long zone_page_state_snapshot(struct zone *zone,
> return x;
> }
>
> +static inline unsigned long node_page_state_snapshot(pg_data_t *pgdat,
> + enum zone_stat_item item)
enum node_stat_item
> +{
> + long x = atomic_long_read(&pgdat->vm_stat[item]);
> +
> +#ifdef CONFIG_SMP
> + int cpu;
> + for_each_online_cpu(cpu)
> + x += per_cpu_ptr(pgdat->per_cpu_nodestats, cpu)->vm_node_stat_diff[item];
> +
> + if (x < 0)
> + x = 0;
> +#endif
> + return x;
> +}
> +
> +
> #ifdef CONFIG_NUMA
> extern unsigned long sum_zone_node_page_state(int node,
> enum zone_stat_item item);
<snip>
> @@ -1147,9 +1147,9 @@ static void free_one_page(struct zone *zone,
> {
> unsigned long nr_scanned;
> spin_lock(&zone->lock);
> - nr_scanned = zone_page_state(zone, NR_PAGES_SCANNED);
> + nr_scanned = node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED);
> if (nr_scanned)
> - __mod_zone_page_state(zone, NR_PAGES_SCANNED, -nr_scanned);
> + __mod_node_page_state(zone->zone_pgdat, NR_PAGES_SCANNED, -nr_scanned);
>
> if (unlikely(has_isolate_pageblock(zone) ||
> is_migrate_isolate(migratetype))) {
> @@ -3526,7 +3526,7 @@ should_reclaim_retry(gfp_t gfp_mask, unsigned order,
>
> available = reclaimable = zone_reclaimable_pages(zone);
> available -= DIV_ROUND_UP(no_progress_loops * available,
> - MAX_RECLAIM_RETRIES);
> + MAX_RECLAIM_RETRIES);
Unnecessary change.
> available += zone_page_state_snapshot(zone, NR_FREE_PAGES);
>
> /*
> @@ -4331,6 +4331,7 @@ void show_free_areas(unsigned int filter)
<snip.
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index e7ffcd259cc4..86a523a761c9 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -191,26 +191,42 @@ static bool sane_reclaim(struct scan_control *sc)
> }
> #endif
>
> +/*
> + * This misses isolated pages which are not accounted for to save counters.
> + * As the data only determines if reclaim or compaction continues, it is
> + * not expected that isolated pages will be a dominating factor.
When I read below commit, one of the reason it was introduced is whether we
should continue to reclaim page or not.
At that time, several people wanted it by my guessing [suggested|acked]-by
so I think we should notice it to them.
Michal?
[9f6c399ddc36, consider isolated pages in zone_reclaimable_pages],
> + */
> unsigned long zone_reclaimable_pages(struct zone *zone)
> {
> unsigned long nr;
>
> - nr = zone_page_state_snapshot(zone, NR_ACTIVE_FILE) +
> - zone_page_state_snapshot(zone, NR_INACTIVE_FILE) +
> - zone_page_state_snapshot(zone, NR_ISOLATED_FILE);
> + nr = zone_page_state_snapshot(zone, NR_ZONE_LRU_FILE);
> + if (get_nr_swap_pages() > 0)
> + nr += zone_page_state_snapshot(zone, NR_ZONE_LRU_ANON);
> +
> + return nr;
> +}
> +