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authorVladimir Davydov <vdavydov@parallels.com>2014-06-05 01:07:20 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-05 01:53:59 +0200
commit03afc0e25f7fc03537014a770f4c54ebbe63a24c (patch)
tree520cdb32e6d35cd5b4e61fc5254a151fb03fc24a /mm/slob.c
parentmem-hotplug: implement get/put_online_mems (diff)
downloadlinux-03afc0e25f7fc03537014a770f4c54ebbe63a24c.tar.xz
linux-03afc0e25f7fc03537014a770f4c54ebbe63a24c.zip
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/slob.c')
-rw-r--r--mm/slob.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/slob.c b/mm/slob.c
index 730cad45d4be..21980e0f39a8 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -620,11 +620,10 @@ int __kmem_cache_shutdown(struct kmem_cache *c)
return 0;
}
-int kmem_cache_shrink(struct kmem_cache *d)
+int __kmem_cache_shrink(struct kmem_cache *d)
{
return 0;
}
-EXPORT_SYMBOL(kmem_cache_shrink);
struct kmem_cache kmem_cache_boot = {
.name = "kmem_cache",