From 4d512a25ca20f3ce37939e91ca1adc75c2b68305 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 3 Jul 2009 08:29:37 -0500 Subject: [PATCH 100/352] mm: page_alloc: rt-friendly per-cpu pages rt-friendly per-cpu pages: convert the irqs-off per-cpu locking method into a preemptible, explicit-per-cpu-locks method. Contains fixes from: Peter Zijlstra Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- mm/page_alloc.c | 57 +++++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 41 insertions(+), 16 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 26ba311..c717779 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -61,6 +61,7 @@ #include #include #include +#include #include #include #include @@ -293,6 +294,18 @@ EXPORT_SYMBOL(nr_node_ids); EXPORT_SYMBOL(nr_online_nodes); #endif +static DEFINE_LOCAL_IRQ_LOCK(pa_lock); + +#ifdef CONFIG_PREEMPT_RT_BASE +# define cpu_lock_irqsave(cpu, flags) \ + spin_lock_irqsave(&per_cpu(pa_lock, cpu).lock, flags) +# define cpu_unlock_irqrestore(cpu, flags) \ + spin_unlock_irqrestore(&per_cpu(pa_lock, cpu).lock, flags) +#else +# define cpu_lock_irqsave(cpu, flags) local_irq_save(flags) +# define cpu_unlock_irqrestore(cpu, flags) local_irq_restore(flags) +#endif + int page_group_by_mobility_disabled __read_mostly; #ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT @@ -1276,10 +1289,10 @@ static void __free_pages_ok(struct page *page, unsigned int order) return; migratetype = get_pfnblock_migratetype(page, pfn); - local_irq_save(flags); + local_lock_irqsave(pa_lock, flags); __count_vm_events(PGFREE, 1 << order); free_one_page(page_zone(page), page, pfn, order, migratetype); - local_irq_restore(flags); + local_unlock_irqrestore(pa_lock, flags); } static void __init __free_pages_boot_core(struct page *page, unsigned int order) @@ -2296,14 +2309,14 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp) unsigned long flags; int to_drain, batch; - local_irq_save(flags); + local_lock_irqsave(pa_lock, flags); batch = READ_ONCE(pcp->batch); to_drain = min(pcp->count, batch); if (to_drain > 0) { free_pcppages_bulk(zone, to_drain, pcp); pcp->count -= to_drain; } - local_irq_restore(flags); + local_unlock_irqrestore(pa_lock, flags); } #endif @@ -2320,7 +2333,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone) struct per_cpu_pageset *pset; struct per_cpu_pages *pcp; - local_irq_save(flags); + cpu_lock_irqsave(cpu, flags); pset = per_cpu_ptr(zone->pageset, cpu); pcp = &pset->pcp; @@ -2328,7 +2341,7 @@ static void drain_pages_zone(unsigned int cpu, struct zone *zone) free_pcppages_bulk(zone, pcp->count, pcp); pcp->count = 0; } - local_irq_restore(flags); + cpu_unlock_irqrestore(cpu, flags); } /* @@ -2415,7 +2428,16 @@ void drain_all_pages(struct zone *zone) else cpumask_clear_cpu(cpu, &cpus_with_pcps); } +#ifndef CONFIG_PREEMPT_RT_BASE on_each_cpu_mask(&cpus_with_pcps, drain_local_pages, zone, 1); +#else + for_each_cpu(cpu, &cpus_with_pcps) { + if (zone) + drain_pages_zone(cpu, zone); + else + drain_pages(cpu); + } +#endif } #ifdef CONFIG_HIBERNATION @@ -2475,7 +2497,7 @@ void free_hot_cold_page(struct page *page, bool cold) migratetype = get_pfnblock_migratetype(page, pfn); set_pcppage_migratetype(page, migratetype); - local_irq_save(flags); + local_lock_irqsave(pa_lock, flags); __count_vm_event(PGFREE); /* @@ -2506,7 +2528,7 @@ void free_hot_cold_page(struct page *page, bool cold) } out: - local_irq_restore(flags); + local_unlock_irqrestore(pa_lock, flags); } /* @@ -2641,7 +2663,7 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, struct per_cpu_pages *pcp; struct list_head *list; - local_irq_save(flags); + local_lock_irqsave(pa_lock, flags); do { pcp = &this_cpu_ptr(zone->pageset)->pcp; list = &pcp->lists[migratetype]; @@ -2668,7 +2690,7 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, * allocate greater than order-1 page units with __GFP_NOFAIL. */ WARN_ON_ONCE((gfp_flags & __GFP_NOFAIL) && (order > 1)); - spin_lock_irqsave(&zone->lock, flags); + local_spin_lock_irqsave(pa_lock, &zone->lock, flags); do { page = NULL; @@ -2680,22 +2702,24 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, if (!page) page = __rmqueue(zone, order, migratetype); } while (page && check_new_pages(page, order)); - spin_unlock(&zone->lock); - if (!page) + if (!page) { + spin_unlock(&zone->lock); goto failed; + } __mod_zone_freepage_state(zone, -(1 << order), get_pcppage_migratetype(page)); + spin_unlock(&zone->lock); } __count_zid_vm_events(PGALLOC, page_zonenum(page), 1 << order); zone_statistics(preferred_zone, zone, gfp_flags); - local_irq_restore(flags); + local_unlock_irqrestore(pa_lock, flags); VM_BUG_ON_PAGE(bad_range(zone, page), page); return page; failed: - local_irq_restore(flags); + local_unlock_irqrestore(pa_lock, flags); return NULL; } @@ -6602,6 +6626,7 @@ static int page_alloc_cpu_notify(struct notifier_block *self, void __init page_alloc_init(void) { hotcpu_notifier(page_alloc_cpu_notify, 0); + local_irq_lock_init(pa_lock); } /* @@ -7443,7 +7468,7 @@ void zone_pcp_reset(struct zone *zone) struct per_cpu_pageset *pset; /* avoid races with drain_pages() */ - local_irq_save(flags); + local_lock_irqsave(pa_lock, flags); if (zone->pageset != &boot_pageset) { for_each_online_cpu(cpu) { pset = per_cpu_ptr(zone->pageset, cpu); @@ -7452,7 +7477,7 @@ void zone_pcp_reset(struct zone *zone) free_percpu(zone->pageset); zone->pageset = &boot_pageset; } - local_irq_restore(flags); + local_unlock_irqrestore(pa_lock, flags); } #ifdef CONFIG_MEMORY_HOTREMOVE -- 2.7.4