From: Jann Horn <[email protected]> When SLAB_VIRTUAL is enabled this new sysfs attribute tracks the number of slab pages whose physical memory has been reclaimed but whose virtual memory is still allocated to a kmem_cache.
Signed-off-by: Jann Horn <[email protected]> Co-developed-by: Matteo Rizzo <[email protected]> Signed-off-by: Matteo Rizzo <[email protected]> --- include/linux/slub_def.h | 4 +++- mm/slub.c | 18 ++++++++++++++++++ 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 693e9bb34edc..eea402d849da 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -88,7 +88,7 @@ struct kmem_cache_cpu { */ struct kmem_cache_virtual { #ifdef CONFIG_SLAB_VIRTUAL - /* Protects freed_slabs and freed_slabs_min */ + /* Protects freed_slabs, freed_slabs_min, and nr_free_pages */ spinlock_t freed_slabs_lock; /* * Slabs on this list have virtual memory of size oo allocated to them @@ -97,6 +97,8 @@ struct kmem_cache_virtual { struct list_head freed_slabs; /* Same as freed_slabs but with memory of size min */ struct list_head freed_slabs_min; + /* Number of slab pages which got freed */ + unsigned long nr_freed_pages; #endif }; diff --git a/mm/slub.c b/mm/slub.c index 66ae60cdadaf..0f7f5bf0b174 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2110,6 +2110,8 @@ static struct slab *get_free_slab(struct kmem_cache *s, if (likely(slab)) { list_del(&slab->slab_list); + WRITE_ONCE(s->virtual.nr_freed_pages, + s->virtual.nr_freed_pages - (1UL << slab_order(slab))); spin_unlock_irqrestore(&s->virtual.freed_slabs_lock, flags); return slab; @@ -2158,6 +2160,8 @@ static struct slab *alloc_slab_page(struct kmem_cache *s, /* Rollback: put the struct slab back. */ spin_lock_irqsave(&s->virtual.freed_slabs_lock, flags); list_add(&slab->slab_list, freed_slabs); + WRITE_ONCE(s->virtual.nr_freed_pages, + s->virtual.nr_freed_pages + (1UL << slab_order(slab))); spin_unlock_irqrestore(&s->virtual.freed_slabs_lock, flags); return NULL; @@ -2438,6 +2442,8 @@ static void slub_tlbflush_worker(struct kthread_work *work) WARN_ON(oo_order(slab->oo) != oo_order(s->min)); list_add(&slab->slab_list, &s->virtual.freed_slabs_min); } + WRITE_ONCE(s->virtual.nr_freed_pages, s->virtual.nr_freed_pages + + (1UL << slab_order(slab))); spin_unlock(&s->virtual.freed_slabs_lock); } spin_unlock_irqrestore(&slub_kworker_lock, irq_flags); @@ -4924,6 +4930,7 @@ static inline void slab_virtual_open(struct kmem_cache *s) spin_lock_init(&s->virtual.freed_slabs_lock); INIT_LIST_HEAD(&s->virtual.freed_slabs); INIT_LIST_HEAD(&s->virtual.freed_slabs_min); + s->virtual.nr_freed_pages = 0; #endif } @@ -6098,6 +6105,14 @@ static ssize_t objects_partial_show(struct kmem_cache *s, char *buf) } SLAB_ATTR_RO(objects_partial); +#ifdef CONFIG_SLAB_VIRTUAL +static ssize_t deallocated_pages_show(struct kmem_cache *s, char *buf) +{ + return sysfs_emit(buf, "%lu\n", READ_ONCE(s->virtual.nr_freed_pages)); +} +SLAB_ATTR_RO(deallocated_pages); +#endif /* CONFIG_SLAB_VIRTUAL */ + static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) { int objects = 0; @@ -6424,6 +6439,9 @@ static struct attribute *slab_attrs[] = { &min_partial_attr.attr, &cpu_partial_attr.attr, &objects_partial_attr.attr, +#ifdef CONFIG_SLAB_VIRTUAL + &deallocated_pages_attr.attr, +#endif &partial_attr.attr, &cpu_slabs_attr.attr, &ctor_attr.attr, -- 2.42.0.459.ge4e396fd5e-goog
