Messages in this thread |  | | | Date | Wed, 5 Oct 2011 09:29:54 +0900 | | From | KAMEZAWA Hiroyuki <> | | Subject | Re: [PATCH v5 0/8] per-cgroup tcp buffer pressure settings |
| |
On Tue, 4 Oct 2011 16:17:52 +0400 Glauber Costa <glommer@parallels.com> wrote:
> [[ v3: merge Kirill's suggestions, + a destroy-related bugfix ]] > [[ v4: Fix a bug with non-mounted cgroups + disallow task movement ]] > [[ v5: Compile bug with modular ipv6 + tcp files in bytes ]] > > Kame, Kirill, > > I am submitting this again merging most of your comments. I've decided to > leave some of them out: > * I am not using res_counters for allocated_memory. Besides being more > expensive than what we need, to make it work in a nice way, we'd have > to change the !cgroup code, including other protocols than tcp. Also, > > * I am not using failcnt and max_usage_in_bytes for it. I believe the value > of those lies more in the allocation than in the pressure control. Besides, > fail conditions lie mostly outside of the memory cgroup's control. (Actually, > a soft_limit makes a lot of sense, and I do plan to introduce it in a follow > up series) > > If you agree with the above, and there are any other pressing issues, let me > know and I will address them ASAP. Otherwise, let's discuss it. I'm always open. >
I'm not familar with reuqirements of users. So, I appreciate your choices. What I adivse you here is taking a deep breath. Making new version every day is not good for reviewing process ;) (It's now -rc8 and merge will not be so quick, anyway.)
At this stage, my concern is view of interfaces and documenation, and future plans.
Let me give a try explanation by myself. (Correct me ;) I added some questions but I'm sorry you've already answered.
New interfaces are 5 files. All files exists only for non-root memory cgroup.
1. memory.independent_kmem_limit 2. memory.kmem.usage_in_bytes 3. memory.kmem.limit_in_bytes 4. memory.kmem.tcp.limit_in_bytes 5. memory.kmem.tcp.usage_in_bytes
* memory.independent_kmem_limit If 1, kmem_limit_in_bytes/kmem_usage_in_bytes works. If 0, kmem_limit_in_bytes/kmem_usage_in_bytes doesn't work and all kmem usages are controlled under memory.limit_in_bytes.
Question: - What happens when parent/chidlren cgroup has different indepedent_kmem_limit ? - What happens at creating a new cgroup with use_hierarchy==1.
* memory.kmem_limit_in_bytes/memory.kmem.tcp.limit_in_bytes
Both files works independently for _Now_. And memory.kmem_usage_in_bytes and memory.kmem_tcp.usage_in_bytes has no relationships.
In future plan, kmem.usage_in_bytes should includes tcp.kmem_usage_in_bytes. And kmem.limit_in_bytes should be the limiation of sum of all kmem.xxxx.limit_in_bytes. Question: - Why this integration is difficult ? Can't tcp-limit-code borrows some amount of charges in batch from kmem_limit and use it ?
- Don't you need a stat file to indicate "tcp memory pressure works!" ? It can be obtained already ?
Thanks, -Kame
|  |