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slub: add fast_slub_nr_free to track free objects 

use lightweight track method to count free objects in
slub, remove heavy logic in spin_lock_irqsave.

Signed-off-by: Xiaoming Gao <newtongao@tencent.com>
This commit is contained in:
Xiaoming Gao 2020-04-21 00:15:09 +08:00
parent b0009bfea9
commit 9de8b674e2
3 changed files with 34 additions and 2 deletions
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3
include/linux/slub_def.h
View File

@ -136,6 +136,9 @@ struct kmem_cache {
struct kasan_cache kasan_info;
#endif
#ifdef CONFIG_SLUB_DEBUG
atomic_long_t total_objects_free;
#endif
struct kmem_cache_node *node[MAX_NUMNODES];
};

9
kernel/sysctl.c
View File

@ -309,6 +309,8 @@ static int min_extfrag_threshold;
static int max_extfrag_threshold = 1000;
#endif
extern unsigned long sysctl_fast_slub_nr_free;
static int sysrq_use_leftctrl_sysctl_handler(struct ctl_table * table ,int write,
void __user *buffer,size_t *lenp,
loff_t *ppos)
@ -1810,6 +1812,13 @@ static struct ctl_table vm_table[] = {
.extra2 = (void *)&mmap_rnd_compat_bits_max,
},
#endif
{
.procname = "fast_slub_nr_free",
.data = &sysctl_fast_slub_nr_free,
.maxlen = sizeof(sysctl_fast_slub_nr_free),
.mode = 0644,
.proc_handler = proc_doulongvec_minmax,
},
{ }
};

24
mm/slub.c
View File

@ -1635,6 +1635,10 @@ out:
inc_slabs_node(s, page_to_nid(page), page->objects);
#ifdef CONFIG_SLUB_DEBUG
atomic_long_add(page->objects, &s->total_objects_free);
#endif
return page;
}
@ -1718,6 +1722,9 @@ static void free_slab(struct kmem_cache *s, struct page *page)
static void discard_slab(struct kmem_cache *s, struct page *page)
{
#ifdef CONFIG_SLUB_DEBUG
atomic_long_sub(page->objects, &s->total_objects_free);
#endif
dec_slabs_node(s, page_to_nid(page), page->objects);
free_slab(s, page);
}
@ -2722,6 +2729,9 @@ redo:
slab_post_alloc_hook(s, gfpflags, 1, &object);
#ifdef CONFIG_SLUB_DEBUG
atomic_long_dec(&s->total_objects_free);
#endif
return object;
}
@ -2957,6 +2967,9 @@ redo:
} else
__slab_free(s, page, head, tail_obj, cnt, addr);
#ifdef CONFIG_SLUB_DEBUG
atomic_long_add(cnt, &s->total_objects_free);
#endif
}
static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
@ -3385,6 +3398,9 @@ static int init_kmem_cache_nodes(struct kmem_cache *s)
{
int node;
#ifdef CONFIG_SLUB_DEBUG
atomic_long_set(&s->total_objects_free, 0);
#endif
for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n;
@ -5837,6 +5853,7 @@ __initcall(slab_sysfs_init);
* The /proc/slabinfo ABI
*/
#ifdef CONFIG_SLABINFO
unsigned long sysctl_fast_slub_nr_free = 0;
void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
{
unsigned long nr_slabs = 0;
@ -5848,9 +5865,12 @@ void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
for_each_kmem_cache_node(s, node, n) {
nr_slabs += node_nr_slabs(n);
nr_objs += node_nr_objs(n);
nr_free += count_partial(n, count_free);
if (!sysctl_fast_slub_nr_free)
nr_free += count_partial(n, count_free);
}
if (sysctl_fast_slub_nr_free)
nr_free = atomic_long_read(&s->total_objects_free);
nr_free = min(nr_objs, nr_free);
sinfo->active_objs = nr_objs - nr_free;
sinfo->num_objs = nr_objs;
sinfo->active_slabs = nr_slabs;