diff options
| -rw-r--r-- | include/linux/mmzone.h | 10 | ||||
| -rw-r--r-- | include/linux/vmstat.h | 5 | ||||
| -rw-r--r-- | mm/mmzone.c | 21 | ||||
| -rw-r--r-- | mm/page_alloc.c | 35 | ||||
| -rw-r--r-- | mm/vmscan.c | 23 | ||||
| -rw-r--r-- | mm/vmstat.c | 68 |
6 files changed, 115 insertions, 47 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 39c24ebe9cfd..48906629335c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -458,12 +458,6 @@ static inline int zone_is_oom_locked(const struct zone *zone) return test_bit(ZONE_OOM_LOCKED, &zone->flags); } -#ifdef CONFIG_SMP -unsigned long zone_nr_free_pages(struct zone *zone); -#else -#define zone_nr_free_pages(zone) zone_page_state(zone, NR_FREE_PAGES) -#endif /* CONFIG_SMP */ - /* * The "priority" of VM scanning is how much of the queues we will scan in one * go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the @@ -661,7 +655,9 @@ typedef struct pglist_data { extern struct mutex zonelists_mutex; void build_all_zonelists(void *data); void wakeup_kswapd(struct zone *zone, int order); -int zone_watermark_ok(struct zone *z, int order, unsigned long mark, +bool zone_watermark_ok(struct zone *z, int order, unsigned long mark, + int classzone_idx, int alloc_flags); +bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark, int classzone_idx, int alloc_flags); enum memmap_context { MEMMAP_EARLY, diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h index eaaea37b3b75..e4cc21cf5870 100644 --- a/include/linux/vmstat.h +++ b/include/linux/vmstat.h @@ -254,6 +254,8 @@ extern void dec_zone_state(struct zone *, enum zone_stat_item); extern void __dec_zone_state(struct zone *, enum zone_stat_item); void refresh_cpu_vm_stats(int); +void reduce_pgdat_percpu_threshold(pg_data_t *pgdat); +void restore_pgdat_percpu_threshold(pg_data_t *pgdat); #else /* CONFIG_SMP */ /* @@ -298,6 +300,9 @@ static inline void __dec_zone_page_state(struct page *page, #define dec_zone_page_state __dec_zone_page_state #define mod_zone_page_state __mod_zone_page_state +static inline void reduce_pgdat_percpu_threshold(pg_data_t *pgdat) { } +static inline void restore_pgdat_percpu_threshold(pg_data_t *pgdat) { } + static inline void refresh_cpu_vm_stats(int cpu) { } #endif diff --git a/mm/mmzone.c b/mm/mmzone.c index e35bfb82c855..f5b7d1760213 100644 --- a/mm/mmzone.c +++ b/mm/mmzone.c @@ -87,24 +87,3 @@ int memmap_valid_within(unsigned long pfn, return 1; } #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ - -#ifdef CONFIG_SMP -/* Called when a more accurate view of NR_FREE_PAGES is needed */ -unsigned long zone_nr_free_pages(struct zone *zone) -{ - unsigned long nr_free_pages = zone_page_state(zone, NR_FREE_PAGES); - - /* - * While kswapd is awake, it is considered the zone is under some - * memory pressure. Under pressure, there is a risk that - * per-cpu-counter-drift will allow the min watermark to be breached - * potentially causing a live-lock. While kswapd is awake and - * free pages are low, get a better estimate for free pages - */ - if (nr_free_pages < zone->percpu_drift_mark && - !waitqueue_active(&zone->zone_pgdat->kswapd_wait)) - return zone_page_state_snapshot(zone, NR_FREE_PAGES); - - return nr_free_pages; -} -#endif /* CONFIG_SMP */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 826ba6922e84..22a1bb7723e4 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1460,24 +1460,24 @@ static inline int should_fail_alloc_page(gfp_t gfp_mask, unsigned int order) #endif /* CONFIG_FAIL_PAGE_ALLOC */ /* - * Return 1 if free pages are above 'mark'. This takes into account the order + * Return true if free pages are above 'mark'. This takes into account the order * of the allocation. */ -int zone_watermark_ok(struct zone *z, int order, unsigned long mark, - int classzone_idx, int alloc_flags) +static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark, + int classzone_idx, int alloc_flags, long free_pages) { /* free_pages my go negative - that's OK */ long min = mark; - long free_pages = zone_nr_free_pages(z) - (1 << order) + 1; int o; + free_pages -= (1 << order) + 1; if (alloc_flags & ALLOC_HIGH) min -= min / 2; if (alloc_flags & ALLOC_HARDER) min -= min / 4; if (free_pages <= min + z->lowmem_reserve[classzone_idx]) - return 0; + return false; for (o = 0; o < order; o++) { /* At the next order, this order's pages become unavailable */ free_pages -= z->free_area[o].nr_free << o; @@ -1486,9 +1486,28 @@ int zone_watermark_ok(struct zone *z, int order, unsigned long mark, min >>= 1; if (free_pages <= min) - return 0; + return false; } - return 1; + return true; +} + +bool zone_watermark_ok(struct zone *z, int order, unsigned long mark, + int classzone_idx, int alloc_flags) +{ + return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags, + zone_page_state(z, NR_FREE_PAGES)); +} + +bool zone_watermark_ok_safe(struct zone *z, int order, unsigned long mark, + int classzone_idx, int alloc_flags) +{ + long free_pages = zone_page_state(z, NR_FREE_PAGES); + + if (z->percpu_drift_mark && free_pages < z->percpu_drift_mark) + free_pages = zone_page_state_snapshot(z, NR_FREE_PAGES); + + return __zone_watermark_ok(z, order, mark, classzone_idx, alloc_flags, + free_pages); } #ifdef CONFIG_NUMA @@ -2442,7 +2461,7 @@ void show_free_areas(void) " all_unreclaimable? %s" "\n", zone->name, - K(zone_nr_free_pages(zone)), + K(zone_page_state(zone, NR_FREE_PAGES)), K(min_wmark_pages(zone)), K(low_wmark_pages(zone)), K(high_wmark_pages(zone)), diff --git a/mm/vmscan.c b/mm/vmscan.c index 9ca587c69274..5da4295e7d67 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2143,7 +2143,7 @@ static int sleeping_prematurely(pg_data_t *pgdat, int order, long remaining) if (zone->all_unreclaimable) continue; - if (!zone_watermark_ok(zone, order, high_wmark_pages(zone), + if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone), 0, 0)) return 1; } @@ -2230,7 +2230,7 @@ loop_again: shrink_active_list(SWAP_CLUSTER_MAX, zone, &sc, priority, 0); - if (!zone_watermark_ok(zone, order, + if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone), 0, 0)) { end_zone = i; break; @@ -2276,7 +2276,7 @@ loop_again: * We put equal pressure on every zone, unless one * zone has way too many pages free already. */ - if (!zone_watermark_ok(zone, order, + if (!zone_watermark_ok_safe(zone, order, 8*high_wmark_pages(zone), end_zone, 0)) shrink_zone(priority, zone, &sc); reclaim_state->reclaimed_slab = 0; @@ -2297,7 +2297,7 @@ loop_again: total_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2) sc.may_writepage = 1; - if (!zone_watermark_ok(zone, order, + if (!zone_watermark_ok_safe(zone, order, high_wmark_pages(zone), end_zone, 0)) { all_zones_ok = 0; /* @@ -2305,7 +2305,7 @@ loop_again: * means that we have a GFP_ATOMIC allocation * failure risk. Hurry up! */ - if (!zone_watermark_ok(zone, order, + if (!zone_watermark_ok_safe(zone, order, min_wmark_pages(zone), end_zone, 0)) has_under_min_watermark_zone = 1; } else { @@ -2448,7 +2448,9 @@ static int kswapd(void *p) */ if (!sleeping_prematurely(pgdat, order, remaining)) { trace_mm_vmscan_kswapd_sleep(pgdat->node_id); + restore_pgdat_percpu_threshold(pgdat); schedule(); + reduce_pgdat_percpu_threshold(pgdat); } else { if (remaining) count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); @@ -2487,16 +2489,17 @@ void wakeup_kswapd(struct zone *zone, int order) if (!populated_zone(zone)) return; - pgdat = zone->zone_pgdat; - if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0)) + if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) return; + pgdat = zone->zone_pgdat; if (pgdat->kswapd_max_order < order) pgdat->kswapd_max_order = order; - trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); - if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL)) - return; if (!waitqueue_active(&pgdat->kswapd_wait)) return; + if (zone_watermark_ok_safe(zone, order, low_wmark_pages(zone), 0, 0)) + return; + + trace_mm_vmscan_wakeup_kswapd(pgdat->node_id, zone_idx(zone), order); wake_up_interruptible(&pgdat->kswapd_wait); } diff --git a/mm/vmstat.c b/mm/vmstat.c index 312d728976f1..bc0f095791b4 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -83,6 +83,30 @@ EXPORT_SYMBOL(vm_stat); #ifdef CONFIG_SMP +static int calculate_pressure_threshold(struct zone *zone) +{ + int threshold; + int watermark_distance; + + /* + * As vmstats are not up to date, there is drift between the estimated + * and real values. For high thresholds and a high number of CPUs, it + * is possible for the min watermark to be breached while the estimated + * value looks fine. The pressure threshold is a reduced value such + * that even the maximum amount of drift will not accidentally breach + * the min watermark + */ + watermark_distance = low_wmark_pages(zone) - min_wmark_pages(zone); + threshold = max(1, (int)(watermark_distance / num_online_cpus())); + + /* + * Maximum threshold is 125 + */ + threshold = min(125, threshold); + + return threshold; +} + static int calculate_threshold(struct zone *zone) { int threshold; @@ -161,6 +185,48 @@ static void refresh_zone_stat_thresholds(void) } } +void reduce_pgdat_percpu_threshold(pg_data_t *pgdat) +{ + struct zone *zone; + int cpu; + int threshold; + int i; + + get_online_cpus(); + for (i = 0; i < pgdat->nr_zones; i++) { + zone = &pgdat->node_zones[i]; + if (!zone->percpu_drift_mark) + continue; + + threshold = calculate_pressure_threshold(zone); + for_each_online_cpu(cpu) + per_cpu_ptr(zone->pageset, cpu)->stat_threshold + = threshold; + } + put_online_cpus(); +} + +void restore_pgdat_percpu_threshold(pg_data_t *pgdat) +{ + struct zone *zone; + int cpu; + int threshold; + int i; + + get_online_cpus(); + for (i = 0; i < pgdat->nr_zones; i++) { + zone = &pgdat->node_zones[i]; + if (!zone->percpu_drift_mark) + continue; + + threshold = calculate_threshold(zone); + for_each_online_cpu(cpu) + per_cpu_ptr(zone->pageset, cpu)->stat_threshold + = threshold; + } + put_online_cpus(); +} + /* * For use when we know that interrupts are disabled. */ @@ -911,7 +977,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, "\n scanned %lu" "\n spanned %lu" "\n present %lu", - zone_nr_free_pages(zone), + zone_page_state(zone, NR_FREE_PAGES), min_wmark_pages(zone), low_wmark_pages(zone), high_wmark_pages(zone), |