linux-kernel - Re: Performance regression in ip_set

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <D2070167-F299-455C-AE4B-5D047ABD5B28@automattic.com>
Date: Sun, 14 Jan 2024 21:38:05 +0100
From: Ale Crismani <ale.crismani@...omattic.com>
To: David Wang <00107082@....com>
Cc: Jozsef Kadlecsik <kadlec@...ckhole.kfki.hu>,
 linux-kernel@...r.kernel.org,
 netfilter-devel@...r.kernel.org,
 Pablo Neira Ayuso <pablo@...filter.org>,
 xiaolinkui@...inos.cn
Subject: Re: Performance regression in ip_set_swap on 6.7.0



> Il giorno 14 gen 2024, alle ore 06:30, David Wang <00107082@....com> ha scritto:
> 
> 
> At 2024-01-14 02:24:07, "Jozsef Kadlecsik" <kadlec@...ckhole.kfki.hu> wrote:
>> On Thu, 11 Jan 2024, David Wang wrote:
>> 
>>> I tested the patch with code stressing swap->destroy->create->add 10000 
>>> times, the performance regression still happens, and now it is 
>>> ip_set_destroy. (I pasted the test code at the end of this mail)
> 
>>> 
>>> They all call wait_for_completion, which may sleep on something on 
>>> purpose, I guess...
>> 
>> That's OK because ip_set_destroy() calls rcu_barrier() which is needed to 
>> handle flush in list type of sets.
>> 
>> However, rcu_barrier() with call_rcu() together makes multiple destroys 
>> one after another slow. But rcu_barrier() is needed for list type of sets 
>> only and that can be handled separately. So could you test the patch 
>> below? According to my tests it is even a little bit faster than the 
>> original code before synchronize_rcu() was added to swap.
> 
> Confirmed~! This patch does fix the performance regression in my case.
> 
> Hope it can fix ale.crismani@...omattic.com's original issue.
> 
> 
> 
> Thanks~
> David


Thanks for all the help on this, I'll try the patch tomorrow hopefully and will report back!

best wishes,
Ale