From: Reinette Chatre <reinette.chatre@intel.com>
To: "Luck, Tony" <tony.luck@intel.com>,
Qinyun Tan <qinyuntan@linux.alibaba.com>
Cc: "H . Peter Anvin" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH] x86/resctrl: Remove unnecessary references to cacheinfo in the resctrl subsystem.
Date: Tue, 27 May 2025 19:59:51 -0700 [thread overview]
Message-ID: <45091ad1-e366-4c56-be94-e15c693da520@intel.com> (raw)
In-Reply-To: <SJ1PR11MB60838CB8BB51EA5B7B9261D6FC67A@SJ1PR11MB6083.namprd11.prod.outlook.com>
Hi Tony,
On 5/27/25 5:14 PM, Luck, Tony wrote:
>>> 2. Lifecycle dependency: The cacheinfo structure's lifecycle is managed
>>> by the cache subsystem, making it unsafe for resctrl to hold
>>> long-term references.
>>
>> This is not obvious to me. Could you please elaborate how resctrl could
>> have a reference to a removed structure?
>
> get_cpu_cacheinfo_level() returns a pointer to a per-cpu structure.
>
> While it appears that those don't get freed and re-used when a CPU is
> taken offline, it does seem highly dubious to keep using one for an
> offline CPU (which is what happens if the first CPU that comes online
> in a domain is taken offline).
I do not understand what your goal is with this response. You seem to
both defend and refute this "lifecycle dependency" motivation/claim.
I am not disagreeing with this fix but I would like to ensure that I
understand all motivations for it.
Reinette
next prev parent reply other threads:[~2025-05-28 2:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-26 7:37 [PATCH] x86/resctrl: Remove unnecessary references to cacheinfo in the resctrl subsystem Qinyun Tan
2025-05-27 21:25 ` Luck, Tony
2025-05-28 2:30 ` qinyuntan
2025-05-27 23:36 ` Reinette Chatre
2025-05-28 0:14 ` Luck, Tony
2025-05-28 2:59 ` Reinette Chatre [this message]
2025-05-28 3:32 ` qinyuntan
2025-05-28 4:49 ` Reinette Chatre
2025-05-28 6:37 ` qinyuntan
2025-05-28 6:40 ` qinyuntan
2025-05-28 17:38 ` Reinette Chatre
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