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Diffstat (limited to '')
| -rw-r--r-- | debian/patches-rt/0075-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/debian/patches-rt/0075-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch b/debian/patches-rt/0075-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch new file mode 100644 index 000000000..c62fd4658 --- /dev/null +++ b/debian/patches-rt/0075-mm-SLUB-delay-giving-back-empty-slubs-to-IRQ-enabled.patch @@ -0,0 +1,223 @@ +From 77ff019039696fc4bd8962110c689eb3520386b1 Mon Sep 17 00:00:00 2001 +From: Thomas Gleixner <tglx@linutronix.de> +Date: Thu, 21 Jun 2018 17:29:19 +0200 +Subject: [PATCH 075/347] mm/SLUB: delay giving back empty slubs to IRQ enabled + regions +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.246-rt110.tar.xz + +__free_slab() is invoked with disabled interrupts which increases the +irq-off time while __free_pages() is doing the work. +Allow __free_slab() to be invoked with enabled interrupts and move +everything from interrupts-off invocations to a temporary per-CPU list +so it can be processed later. + +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + mm/slub.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++---- + 1 file changed, 69 insertions(+), 5 deletions(-) + +diff --git a/mm/slub.c b/mm/slub.c +index 0e4670add1e9..a5a086ed4493 100644 +--- a/mm/slub.c ++++ b/mm/slub.c +@@ -1350,6 +1350,12 @@ static bool freelist_corrupted(struct kmem_cache *s, struct page *page, + } + #endif /* CONFIG_SLUB_DEBUG */ + ++struct slub_free_list { ++ raw_spinlock_t lock; ++ struct list_head list; ++}; ++static DEFINE_PER_CPU(struct slub_free_list, slub_free_list); ++ + /* + * Hooks for other subsystems that check memory allocations. In a typical + * production configuration these hooks all should produce no code at all. +@@ -1711,6 +1717,16 @@ static void __free_slab(struct kmem_cache *s, struct page *page) + __free_pages(page, order); + } + ++static void free_delayed(struct list_head *h) ++{ ++ while (!list_empty(h)) { ++ struct page *page = list_first_entry(h, struct page, lru); ++ ++ list_del(&page->lru); ++ __free_slab(page->slab_cache, page); ++ } ++} ++ + static void rcu_free_slab(struct rcu_head *h) + { + struct page *page = container_of(h, struct page, rcu_head); +@@ -1722,6 +1738,12 @@ static void free_slab(struct kmem_cache *s, struct page *page) + { + if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) { + call_rcu(&page->rcu_head, rcu_free_slab); ++ } else if (irqs_disabled()) { ++ struct slub_free_list *f = this_cpu_ptr(&slub_free_list); ++ ++ raw_spin_lock(&f->lock); ++ list_add(&page->lru, &f->list); ++ raw_spin_unlock(&f->lock); + } else + __free_slab(s, page); + } +@@ -2256,14 +2278,21 @@ static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) + pobjects = oldpage->pobjects; + pages = oldpage->pages; + if (drain && pobjects > s->cpu_partial) { ++ struct slub_free_list *f; + unsigned long flags; ++ LIST_HEAD(tofree); + /* + * partial array is full. Move the existing + * set to the per node partial list. + */ + local_irq_save(flags); + unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); ++ f = this_cpu_ptr(&slub_free_list); ++ raw_spin_lock(&f->lock); ++ list_splice_init(&f->list, &tofree); ++ raw_spin_unlock(&f->lock); + local_irq_restore(flags); ++ free_delayed(&tofree); + oldpage = NULL; + pobjects = 0; + pages = 0; +@@ -2333,7 +2362,22 @@ static bool has_cpu_slab(int cpu, void *info) + + static void flush_all(struct kmem_cache *s) + { ++ LIST_HEAD(tofree); ++ int cpu; ++ + on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC); ++ for_each_online_cpu(cpu) { ++ struct slub_free_list *f; ++ ++ if (!has_cpu_slab(cpu, s)) ++ continue; ++ ++ f = &per_cpu(slub_free_list, cpu); ++ raw_spin_lock_irq(&f->lock); ++ list_splice_init(&f->list, &tofree); ++ raw_spin_unlock_irq(&f->lock); ++ free_delayed(&tofree); ++ } + } + + /* +@@ -2531,8 +2575,10 @@ static inline void *get_freelist(struct kmem_cache *s, struct page *page) + * already disabled (which is the case for bulk allocation). + */ + static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, +- unsigned long addr, struct kmem_cache_cpu *c) ++ unsigned long addr, struct kmem_cache_cpu *c, ++ struct list_head *to_free) + { ++ struct slub_free_list *f; + void *freelist; + struct page *page; + +@@ -2598,6 +2644,13 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + VM_BUG_ON(!c->page->frozen); + c->freelist = get_freepointer(s, freelist); + c->tid = next_tid(c->tid); ++ ++out: ++ f = this_cpu_ptr(&slub_free_list); ++ raw_spin_lock(&f->lock); ++ list_splice_init(&f->list, to_free); ++ raw_spin_unlock(&f->lock); ++ + return freelist; + + new_slab: +@@ -2613,7 +2666,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + + if (unlikely(!freelist)) { + slab_out_of_memory(s, gfpflags, node); +- return NULL; ++ goto out; + } + + page = c->page; +@@ -2626,7 +2679,7 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + goto new_slab; /* Slab failed checks. Next slab needed */ + + deactivate_slab(s, page, get_freepointer(s, freelist), c); +- return freelist; ++ goto out; + } + + /* +@@ -2638,6 +2691,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + { + void *p; + unsigned long flags; ++ LIST_HEAD(tofree); + + local_irq_save(flags); + #ifdef CONFIG_PREEMPT +@@ -2649,8 +2703,9 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, + c = this_cpu_ptr(s->cpu_slab); + #endif + +- p = ___slab_alloc(s, gfpflags, node, addr, c); ++ p = ___slab_alloc(s, gfpflags, node, addr, c, &tofree); + local_irq_restore(flags); ++ free_delayed(&tofree); + return p; + } + +@@ -3130,6 +3185,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, + void **p) + { + struct kmem_cache_cpu *c; ++ LIST_HEAD(to_free); + int i; + + /* memcg and kmem_cache debug support */ +@@ -3162,7 +3218,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, + * of re-populating per CPU c->freelist + */ + p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE, +- _RET_IP_, c); ++ _RET_IP_, c, &to_free); + if (unlikely(!p[i])) + goto error; + +@@ -3174,6 +3230,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, + } + c->tid = next_tid(c->tid); + local_irq_enable(); ++ free_delayed(&to_free); + + /* Clear memory outside IRQ disabled fastpath loop */ + if (unlikely(flags & __GFP_ZERO)) { +@@ -3188,6 +3245,7 @@ int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, + return i; + error: + local_irq_enable(); ++ free_delayed(&to_free); + slab_post_alloc_hook(s, flags, i, p); + __kmem_cache_free_bulk(s, i, p); + return 0; +@@ -4237,6 +4295,12 @@ void __init kmem_cache_init(void) + { + static __initdata struct kmem_cache boot_kmem_cache, + boot_kmem_cache_node; ++ int cpu; ++ ++ for_each_possible_cpu(cpu) { ++ raw_spin_lock_init(&per_cpu(slub_free_list, cpu).lock); ++ INIT_LIST_HEAD(&per_cpu(slub_free_list, cpu).list); ++ } + + if (debug_guardpage_minorder()) + slub_max_order = 0; +-- +2.36.1 + |