linux-kernel - Re: [PATCH v2 2/8] sched/topology: Wrappers for sched_domains

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: <67a401e5-6cef-4f4c-a31b-7c2793666e40@redhat.com>
Date: Fri, 7 Mar 2025 11:34:09 -0500
From: Waiman Long <llong@...hat.com>
To: Juri Lelli <juri.lelli@...hat.com>, Waiman Long <llong@...hat.com>
Cc: linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
 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>,
 Tejun Heo <tj@...nel.org>, Johannes Weiner <hannes@...xchg.org>,
 Michal Koutný <mkoutny@...e.com>,
 Qais Yousef <qyousef@...alina.io>,
 Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
 Swapnil Sapkal <swapnil.sapkal@....com>,
 Shrikanth Hegde <sshegde@...ux.ibm.com>, Phil Auld <pauld@...hat.com>,
 luca.abeni@...tannapisa.it, tommaso.cucinotta@...tannapisa.it,
 Jon Hunter <jonathanh@...dia.com>
Subject: Re: [PATCH v2 2/8] sched/topology: Wrappers for sched_domains_mutex

On 3/7/25 10:59 AM, Juri Lelli wrote:
> On 07/03/25 10:19, Waiman Long wrote:
>> On 3/7/25 10:11 AM, Waiman Long wrote:
>>> On 3/6/25 9:10 AM, Juri Lelli wrote:
>>>> Create wrappers for sched_domains_mutex so that it can transparently be
>>>> used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
>>>> do.
>>>>
>>>> Reported-by: Jon Hunter <jonathanh@...dia.com>
>>>> Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow
>>>> earlier for hotplug")
>>>> Signed-off-by: Juri Lelli <juri.lelli@...hat.com>
>>>> ---
>>>> v1 -> v2: Remove wrappers for the !SMP case as all users are not defined
>>>>             either in that case
>>>> ---
>>>>    include/linux/sched.h   |  2 ++
>>>>    kernel/cgroup/cpuset.c  |  4 ++--
>>>>    kernel/sched/core.c     |  4 ++--
>>>>    kernel/sched/debug.c    |  8 ++++----
>>>>    kernel/sched/topology.c | 12 ++++++++++--
>>>>    5 files changed, 20 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/include/linux/sched.h b/include/linux/sched.h
>>>> index 9632e3318e0d..d5f8c161d852 100644
>>>> --- a/include/linux/sched.h
>>>> +++ b/include/linux/sched.h
>>>> @@ -383,6 +383,8 @@ enum uclamp_id {
>>>>    extern struct root_domain def_root_domain;
>>>>    extern struct mutex sched_domains_mutex;
>>>>    #endif
>>>> +extern void sched_domains_mutex_lock(void);
>>>> +extern void sched_domains_mutex_unlock(void);
>>> As discussed in the other thread, move the
>>> sched_domains_mutex_{lock/unlock}{} inside the "#if CONFIG_SMP" block
>>> and define the else part so that it can be used in code block that will
>>> also be compiled in the !CONFIG_SMP case.
>>>
>>> Other than that, the rest looks good to me.
>> Actually, you can also remove sched_domains_mutex from the header and make
>> it static as it is no longer directly accessed.
> Apart from a lockdep_assert_held() in cpuset.c, no? Guess I can create a
> wrapper for that, but is it really better?

I forgot about that. Please ignore this comment.

Thanks,
Longman