linux-kernel - Re: [PATCH v2 3/2] sched/deadline: Check bandwidth overflow earlier for hotplug

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: <aebb2c29-2224-4d14-94e0-7a495923b401@nvidia.com>
Date: Thu, 16 Jan 2025 13:14:33 +0000
From: Jon Hunter <jonathanh@...dia.com>
To: Juri Lelli <juri.lelli@...hat.com>
Cc: Thierry Reding <treding@...dia.com>, Waiman Long <longman@...hat.com>,
 Tejun Heo <tj@...nel.org>, Johannes Weiner <hannes@...xchg.org>,
 Michal Koutny <mkoutny@...e.com>, Ingo Molnar <mingo@...hat.com>,
 Peter Zijlstra <peterz@...radead.org>,
 Vincent Guittot <vincent.guittot@...aro.org>,
 Dietmar Eggemann <dietmar.eggemann@....com>,
 Steven Rostedt <rostedt@...dmis.org>, Ben Segall <bsegall@...gle.com>,
 Mel Gorman <mgorman@...e.de>, Valentin Schneider <vschneid@...hat.com>,
 Phil Auld <pauld@...hat.com>, Qais Yousef <qyousef@...alina.io>,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 "Joel Fernandes (Google)" <joel@...lfernandes.org>,
 Suleiman Souhlal <suleiman@...gle.com>, Aashish Sharma <shraash@...gle.com>,
 Shin Kawamura <kawasin@...gle.com>,
 Vineeth Remanan Pillai <vineeth@...byteword.org>,
 linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
 "linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v2 3/2] sched/deadline: Check bandwidth overflow earlier
 for hotplug


On 15/01/2025 16:10, Juri Lelli wrote:
> On 14/01/25 15:02, Juri Lelli wrote:
>> On 14/01/25 13:52, Jon Hunter wrote:
>>>
>>> On 13/01/2025 09:32, Juri Lelli wrote:
>>>> On 10/01/25 18:40, Jon Hunter wrote:
>>>>
>>>> ...
>>>>
>>>>> With the above I see the following ...
>>>>>
>>>>> [   53.919672] dl_bw_manage: cpu=5 cap=3072 fair_server_bw=52428 total_bw=209712 dl_bw_cpus=4
>>>>> [   53.930608] dl_bw_manage: cpu=4 cap=2048 fair_server_bw=52428 total_bw=157284 dl_bw_cpus=3
>>>>> [   53.941601] dl_bw_manage: cpu=3 cap=1024 fair_server_bw=52428 total_bw=104856 dl_bw_cpus=2
>>>>
>>>> So far so good.
>>>>
>>>>> [   53.952186] dl_bw_manage: cpu=2 cap=1024 fair_server_bw=52428 total_bw=576708 dl_bw_cpus=2
>>>>
>>>> But, this above doesn't sound right.
>>>>
>>>>> [   53.962938] dl_bw_manage: cpu=1 cap=0 fair_server_bw=52428 total_bw=576708 dl_bw_cpus=1
>>>>> [   53.971068] Error taking CPU1 down: -16
>>>>> [   53.974912] Non-boot CPUs are not disabled
>>>>
>>>> What is the topology of your board?
>>>>
>>>> Are you using any cpuset configuration for partitioning CPUs?
>>>
>>>
>>> I just noticed that by default we do boot this board with 'isolcpus=1-2'. I
>>> see that this is a deprecated cmdline argument now and I must admit I don't
>>> know the history of this for this specific board. It is quite old now.
>>>
>>> Thierry, I am curious if you have this set for Tegra186 or not? Looks like
>>> our BSP (r35 based) sets this by default.
>>>
>>> I did try removing this and that does appear to fix it.
>>
>> OK, good.
>>
>>> Juri, let me know your thoughts.
>>
>> Thanks for the additional info. I guess I could now try to repro using
>> isolcpus at boot on systems I have access to (to possibly understand
>> what the underlying problem is).
> 
> I think the problem lies in the def_root_domain accounting of dl_servers
> (which isolated cpus remains attached to).
> 
> Came up with the following, of which I'm not yet fully convinced, but
> could you please try it out on top of the debug patch and see how it
> does with the original failing setup using isolcpus?


Thanks I added the change, but suspend is still failing with this ...

[  210.595431] dl_bw_manage: cpu=5 cap=3072 fair_server_bw=52428 total_bw=209712 dl_bw_cpus=4
[  210.606269] dl_bw_manage: cpu=4 cap=2048 fair_server_bw=52428 total_bw=157284 dl_bw_cpus=3
[  210.617281] dl_bw_manage: cpu=3 cap=1024 fair_server_bw=52428 total_bw=104856 dl_bw_cpus=2
[  210.627205] dl_bw_manage: cpu=2 cap=1024 fair_server_bw=52428 total_bw=262140 dl_bw_cpus=2
[  210.637752] dl_bw_manage: cpu=1 cap=0 fair_server_bw=52428 total_bw=262140 dl_bw_cpus=1
[  210.645858] Error taking CPU1 down: -16
[  210.649713] Non-boot CPUs are not disabled

Jon

-- 
nvpublic