On Fri, 30 May 2014, Vladimir Davydov wrote: > There is no use in keeping free objects/slabs on dead memcg caches, > because they will never be allocated. So let's make cache_reap() shrink > as many free objects from such caches as possible. > > Note the difference between SLAB and SLUB handling of dead memcg caches. > For SLUB, dead cache destruction is scheduled as soon as the last object > is freed, because dead caches do not cache free objects. For SLAB, dead > caches can keep some free objects on per cpu arrays, so that an empty > dead cache will be hanging around until cache_reap() drains it. Calling kmem_cache_shrink() should drain all caches though. Reduce the size of the queues to zero or so before calling shrink so that no new caches are build up? > We don't disable free objects caching for SLAB, because it would force > kfree to always take a spin lock, which would degrade performance > significantly. You can use a similar approach than in SLUB. Reduce the size of the per cpu array objects to zero. Then SLAB will always fall back to its slow path in cache_flusharray() where you may be able to do something with less of an impact on performace. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>