On Thu, 18 Jun 2020 18:27:12 -0700 Roman Gushchin <guro@xxxxxx> wrote: > Theoretically speaking it should get worse (especially for non-root allocations), > but if the difference is not big, it still should be better, because there is > a big expected win from memory savings/smaller working set/less fragmentation etc. > > The only thing I'm slightly worried is what's the effect on root allocations > if we're sharing slab caches between root- and non-root allocations. Because if > someone depends so much on the allocation speed, memcg-based accounting can be > ignored anyway. For most users the cost of allocation is negligible. > That's why the patch which merges root- and memcg slab caches is put on top > and can be reverted if somebody will complain. In general I like this work for saving memory, but you also have to be aware of the negative consequences of sharing slab caches. At Red Hat we have experienced very hard to find kernel bugs, that point to memory corruption at a completely wrong kernel code, because other kernel code were corrupting the shared slab cache. (Hint a workaround is to enable SLUB debugging to disable this sharing). -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
