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Message-ID: <d40b3d06-b0b9-40c2-a7bb-19e19d5a3803@intel.com>
Date: Mon, 8 Apr 2024 20:53:53 -0700
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v1 1/6] x86/resctrl: Move __resctrl_sched_in() out-of-line
To: Peter Newman <peternewman@google.com>
CC: Fenghua Yu <fenghua.yu@intel.com>, James Morse <james.morse@arm.com>,
	Stephane Eranian <eranian@google.com>, Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>, Dave Hansen
	<dave.hansen@linux.intel.com>, <x86@kernel.org>, "H. Peter Anvin"
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	<juri.lelli@redhat.com>, Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>, Steven Rostedt
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	<mgorman@suse.de>, Daniel Bristot de Oliveira <bristot@redhat.com>, "Valentin
 Schneider" <vschneid@redhat.com>, Uros Bizjak <ubizjak@gmail.com>, "Mike
 Rapoport" <rppt@kernel.org>, "Kirill A. Shutemov"
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	<rick.p.edgecombe@intel.com>, Xin Li <xin3.li@intel.com>, Babu Moger
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	<beaub@linux.microsoft.com>, "Matthew Wilcox (Oracle)" <willy@infradead.org>,
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References: <20240325172707.73966-1-peternewman@google.com>
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 <e2c479b6-43f0-4e2c-9ccd-2e5f322d1974@intel.com>
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 <CALPaoCiX-EZu-SNt-1A9QNJyc27jqmr9LNJ2r4Eq_fChGhgscQ@mail.gmail.com>
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From: Reinette Chatre <reinette.chatre@intel.com>
In-Reply-To: <CALPaoCiX-EZu-SNt-1A9QNJyc27jqmr9LNJ2r4Eq_fChGhgscQ@mail.gmail.com>
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Hi Peter,

On 4/8/2024 2:41 PM, Peter Newman wrote:
> On Mon, Apr 8, 2024 at 1:59 PM Reinette Chatre
> <reinette.chatre@intel.com> wrote:
>> On 4/8/2024 12:05 PM, Peter Newman wrote:
>>> On Sun, Apr 7, 2024 at 12:21 PM Reinette Chatre
>>> <reinette.chatre@intel.com> wrote:

>>> wrappers for the mon and alloc enable keys[1], so I can only assume
>>> they are architecture-independent in concept.
>>
>> The wrappers are intended to be architecture-independent, but the keys
>> are architecture dependent. Quoting the commit you linked to:
>> "This means other architectures don't have to mirror the static keys"
> 
> The static keys seem to exist mainly for the benefit of
> __resctrl_sched_in(), so if it becomes architecture-agnostic, I think
> it would make sense for the static keys to move into the FS code with
> it. I don't see any other usage of these keys in the code that
> remained under arch/x86 on James' latest series.

Good point. James untangled the static keys from multiple usages with
only context switching remaining.
If its only use remains to avoid runtime checks in __resctrl_sched_in()
then it sounds reasonable that the static keys follow
__resctrl_sched_in() to FS code.

Reinette