On Thu 15-11-12 06:47:32, Tejun Heo wrote: > Hello, Michal. > > On Thu, Nov 15, 2012 at 10:51:03AM +0100, Michal Hocko wrote: > > > I'm a bit confused. Why would that make any difference? Shouldn't it > > > be just able to test the condition and continue? > > > > Ohh, I misunderstood your proposal. So what you are suggesting is > > to put all the logic we have in mem_cgroup_iter inside what you call > > reclaim here + mem_cgroup_iter_break inside the loop, right? > > > > I do not see how this would help us much. mem_cgroup_iter is not the > > nicest piece of code but it handles quite a complex requirements that we > > have currently (css reference count, multiple reclaimers racing). So I > > would rather keep it this way. Further simplifications are welcome of > > course. > > > > Is there any reason why you are not happy about direct using of > > cgroup_next_descendant_pre? > > Because I'd like to consider the next functions as implementation > detail, and having interations structred as loops tend to read better > and less error-prone. e.g. when you use next functions directly, it's > way easier to circumvent locking requirements in a way which isn't > very obvious.
The whole point behind mem_cgroup_iter is to hide all the complexity behind memcg iteration. Memcg code either use for_each_mem_cgroup_tree for !reclaim case and mem_cgroup_iter otherwise. > So, unless it messes up the code too much (and I can't see why it > would), I'd much prefer if memcg used for_each_*() macros. As I said this would mean that the current mem_cgroup_iter code would have to be inverted which doesn't simplify the code much. I'd rather hide all the grossy details inside the memcg iterator. Or am I still missing your suggestion? -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
