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author | Vladimir Davydov <vdavydov@parallels.com> | 2014-06-04 16:07:20 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-06-04 16:53:59 -0700 |
commit | 03afc0e25f7fc03537014a770f4c54ebbe63a24c (patch) | |
tree | 520cdb32e6d35cd5b4e61fc5254a151fb03fc24a /mm/slab_common.c | |
parent | bfc8c90139ebd049b9801a951db3b9a4a00bed9c (diff) | |
download | linux-03afc0e25f7fc03537014a770f4c54ebbe63a24c.tar.bz2 |
slab: get_online_mems for kmem_cache_{create,destroy,shrink}
When we create a sl[au]b cache, we allocate kmem_cache_node structures
for each online NUMA node. To handle nodes taken online/offline, we
register memory hotplug notifier and allocate/free kmem_cache_node
corresponding to the node that changes its state for each kmem cache.
To synchronize between the two paths we hold the slab_mutex during both
the cache creationg/destruction path and while tuning per-node parts of
kmem caches in memory hotplug handler, but that's not quite right,
because it does not guarantee that a newly created cache will have all
kmem_cache_nodes initialized in case it races with memory hotplug. For
instance, in case of slub:
CPU0 CPU1
---- ----
kmem_cache_create: online_pages:
__kmem_cache_create: slab_memory_callback:
slab_mem_going_online_callback:
lock slab_mutex
for each slab_caches list entry
allocate kmem_cache node
unlock slab_mutex
lock slab_mutex
init_kmem_cache_nodes:
for_each_node_state(node, N_NORMAL_MEMORY)
allocate kmem_cache node
add kmem_cache to slab_caches list
unlock slab_mutex
online_pages (continued):
node_states_set_node
As a result we'll get a kmem cache with not all kmem_cache_nodes
allocated.
To avoid issues like that we should hold get/put_online_mems() during
the whole kmem cache creation/destruction/shrink paths, just like we
deal with cpu hotplug. This patch does the trick.
Note, that after it's applied, there is no need in taking the slab_mutex
for kmem_cache_shrink any more, so it is removed from there.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r-- | mm/slab_common.c | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c index 2834bc2886fd..2dd920dc3776 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -205,6 +205,8 @@ kmem_cache_create(const char *name, size_t size, size_t align, int err; get_online_cpus(); + get_online_mems(); + mutex_lock(&slab_mutex); err = kmem_cache_sanity_check(name, size); @@ -239,6 +241,8 @@ kmem_cache_create(const char *name, size_t size, size_t align, out_unlock: mutex_unlock(&slab_mutex); + + put_online_mems(); put_online_cpus(); if (err) { @@ -272,6 +276,8 @@ void kmem_cache_create_memcg(struct mem_cgroup *memcg, struct kmem_cache *root_c char *cache_name; get_online_cpus(); + get_online_mems(); + mutex_lock(&slab_mutex); /* @@ -295,6 +301,8 @@ void kmem_cache_create_memcg(struct mem_cgroup *memcg, struct kmem_cache *root_c out_unlock: mutex_unlock(&slab_mutex); + + put_online_mems(); put_online_cpus(); } @@ -328,6 +336,8 @@ void slab_kmem_cache_release(struct kmem_cache *s) void kmem_cache_destroy(struct kmem_cache *s) { get_online_cpus(); + get_online_mems(); + mutex_lock(&slab_mutex); s->refcount--; @@ -359,15 +369,36 @@ void kmem_cache_destroy(struct kmem_cache *s) #else slab_kmem_cache_release(s); #endif - goto out_put_cpus; + goto out; out_unlock: mutex_unlock(&slab_mutex); -out_put_cpus: +out: + put_online_mems(); put_online_cpus(); } EXPORT_SYMBOL(kmem_cache_destroy); +/** + * kmem_cache_shrink - Shrink a cache. + * @cachep: The cache to shrink. + * + * Releases as many slabs as possible for a cache. + * To help debugging, a zero exit status indicates all slabs were released. + */ +int kmem_cache_shrink(struct kmem_cache *cachep) +{ + int ret; + + get_online_cpus(); + get_online_mems(); + ret = __kmem_cache_shrink(cachep); + put_online_mems(); + put_online_cpus(); + return ret; +} +EXPORT_SYMBOL(kmem_cache_shrink); + int slab_is_available(void) { return slab_state >= UP; |