Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:5 as permitted sender) client-ip=2620:137:e000::3:5;
Message-ID: <8d6bf3e9-5e44-cd83-bc49-c9dddd7b6b03@bytedance.com>
Date:   Fri, 15 Sep 2023 16:47:22 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0)
 Gecko/20100101 Thunderbird/102.15.1
Subject: Re: Re: [RFC PATCH net-next 0/3] sock: Be aware of memcg pressure on
 alloc
To:     Shakeel Butt <shakeelb@google.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Michal Hocko <mhocko@suse.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Yosry Ahmed <yosryahmed@google.com>,
        "Matthew Wilcox (Oracle)" <willy@infradead.org>,
        Yu Zhao <yuzhao@google.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Yafang Shao <laoar.shao@gmail.com>,
        Kuniyuki Iwashima <kuniyu@amazon.com>,
        Martin KaFai Lau <martin.lau@kernel.org>,
        Breno Leitao <leitao@debian.org>,
        Alexander Mikhalitsyn <alexander@mihalicyn.com>,
        David Howells <dhowells@redhat.com>,
        Jason Xing <kernelxing@tencent.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@vger.kernel.org>,
        "open list:MEMORY MANAGEMENT" <linux-mm@kvack.org>
References: <20230901062141.51972-1-wuyun.abel@bytedance.com>
 <20230914212042.nnubjht3huiap3kk@google.com>
Content-Language: en-US
From:   Abel Wu <wuyun.abel@bytedance.com>
In-Reply-To: <20230914212042.nnubjht3huiap3kk@google.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 9/15/23 5:20 AM, Shakeel Butt wrote:
> On Fri, Sep 01, 2023 at 02:21:25PM +0800, Abel Wu wrote:
>>
> [...]
>> As expected, no obvious performance gain or loss observed. As for the
>> issue we encountered, this patchset provides better worst-case behavior
>> that such OOM cases are reduced at some extent. While further fine-
>> grained traffic control is what the workloads need to think about.
>>
> 
> I agree with the motivation but I don't agree with the solution (patch 2
> and 3). This is adding one more heuristic in the code which you yourself
> described as helped to some extent. In addition adding more dependency
> on vmpressure subsystem which is in weird state. Vmpressure is a cgroup
> v1 feature which somehow networking subsystem is relying on for cgroup
> v2 deployments. In addition vmpressure acts differently for workloads
> with different memory types (mapped, mlocked, kernel memory).

Indeed.

> 
> Anyways, have you explored the BPF based approach. You can induce socket
> pressure at the points you care about and define memory pressure however
> your use-case cares for. You can define memory pressure using PSI or
> vmpressure or maybe with MEMCG_HIGH events. What do you think?

Yeah, this sounds much better. I will re-implement this patchset based
on your suggestion. Thank you for helpful comments!

Best,
	Abel