kmem_cache->cpu_partial is just used when CONFIG_SLUB_CPU_PARTIAL is set, so wrap it with config CONFIG_SLUB_CPU_PARTIAL will save some space on 32bit arch.
This patch wrap kmem_cache->cpu_partial in config CONFIG_SLUB_CPU_PARTIAL and wrap its sysfs too. Signed-off-by: Wei Yang <[email protected]> --- include/linux/slub_def.h | 2 ++ mm/slub.c | 72 +++++++++++++++++++++++++++++------------------- 2 files changed, 46 insertions(+), 28 deletions(-) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 0debd8df1a7d..477ab99800ed 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -69,7 +69,9 @@ struct kmem_cache { int size; /* The size of an object including meta data */ int object_size; /* The size of an object without meta data */ int offset; /* Free pointer offset. */ +#ifdef CONFIG_SLUB_CPU_PARTIAL int cpu_partial; /* Number of per cpu partial objects to keep around */ +#endif struct kmem_cache_order_objects oo; /* Allocation and freeing of slabs */ diff --git a/mm/slub.c b/mm/slub.c index fde499b6dad8..94978f27882a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1829,7 +1829,10 @@ static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, stat(s, CPU_PARTIAL_NODE); } if (!kmem_cache_has_cpu_partial(s) - || available > s->cpu_partial / 2) +#ifdef CONFIG_SLUB_CPU_PARTIAL + || available > s->cpu_partial / 2 +#endif + ) break; } @@ -3418,6 +3421,39 @@ static void set_min_partial(struct kmem_cache *s, unsigned long min) s->min_partial = min; } +static void set_cpu_partial(struct kmem_cache *s) +{ +#ifdef CONFIG_SLUB_CPU_PARTIAL + /* + * cpu_partial determined the maximum number of objects kept in the + * per cpu partial lists of a processor. + * + * Per cpu partial lists mainly contain slabs that just have one + * object freed. If they are used for allocation then they can be + * filled up again with minimal effort. The slab will never hit the + * per node partial lists and therefore no locking will be required. + * + * This setting also determines + * + * A) The number of objects from per cpu partial slabs dumped to the + * per node list when we reach the limit. + * B) The number of objects in cpu partial slabs to extract from the + * per node list when we run out of per cpu objects. We only fetch + * 50% to keep some capacity around for frees. + */ + if (!kmem_cache_has_cpu_partial(s)) + s->cpu_partial = 0; + else if (s->size >= PAGE_SIZE) + s->cpu_partial = 2; + else if (s->size >= 1024) + s->cpu_partial = 6; + else if (s->size >= 256) + s->cpu_partial = 13; + else + s->cpu_partial = 30; +#endif +} + /* * calculate_sizes() determines the order and the distribution of data within * a slab object. @@ -3576,33 +3612,7 @@ static int kmem_cache_open(struct kmem_cache *s, unsigned long flags) */ set_min_partial(s, ilog2(s->size) / 2); - /* - * cpu_partial determined the maximum number of objects kept in the - * per cpu partial lists of a processor. - * - * Per cpu partial lists mainly contain slabs that just have one - * object freed. If they are used for allocation then they can be - * filled up again with minimal effort. The slab will never hit the - * per node partial lists and therefore no locking will be required. - * - * This setting also determines - * - * A) The number of objects from per cpu partial slabs dumped to the - * per node list when we reach the limit. - * B) The number of objects in cpu partial slabs to extract from the - * per node list when we run out of per cpu objects. We only fetch - * 50% to keep some capacity around for frees. - */ - if (!kmem_cache_has_cpu_partial(s)) - s->cpu_partial = 0; - else if (s->size >= PAGE_SIZE) - s->cpu_partial = 2; - else if (s->size >= 1024) - s->cpu_partial = 6; - else if (s->size >= 256) - s->cpu_partial = 13; - else - s->cpu_partial = 30; + set_cpu_partial(s); #ifdef CONFIG_NUMA s->remote_node_defrag_ratio = 1000; @@ -3989,7 +3999,9 @@ void __kmemcg_cache_deactivate(struct kmem_cache *s) * Disable empty slabs caching. Used to avoid pinning offline * memory cgroups by kmem pages that can be freed. */ +#ifdef CONFIG_SLUB_CPU_PARTIAL s->cpu_partial = 0; +#endif s->min_partial = 0; /* @@ -4929,6 +4941,7 @@ static ssize_t min_partial_store(struct kmem_cache *s, const char *buf, } SLAB_ATTR(min_partial); +#ifdef CONFIG_SLUB_CPU_PARTIAL static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf) { return sprintf(buf, "%u\n", s->cpu_partial); @@ -4951,6 +4964,7 @@ static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf, return length; } SLAB_ATTR(cpu_partial); +#endif static ssize_t ctor_show(struct kmem_cache *s, char *buf) { @@ -5363,7 +5377,9 @@ static struct attribute *slab_attrs[] = { &objs_per_slab_attr.attr, &order_attr.attr, &min_partial_attr.attr, +#ifdef CONFIG_SLUB_CPU_PARTIAL &cpu_partial_attr.attr, +#endif &objects_attr.attr, &objects_partial_attr.attr, &partial_attr.attr, -- 2.11.0
