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From: Borislav Petkov <bp@alien8.de>
To: Reinette Chatre <reinette.chatre@intel.com>
Cc: tglx@linutronix.de, fenghua.yu@intel.com, tony.luck@intel.com,
	kuo-lang.tseng@intel.com, mingo@redhat.com, babu.moger@amd.com,
	hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] x86/resctrl: Support CPUID enumeration of MBM counter width
Date: Thu, 30 Apr 2020 11:59:13 +0200	[thread overview]
Message-ID: <20200430095913.GA3996@zn.tnic> (raw)
In-Reply-To: <6fb58472-88f2-925b-3a4e-4692957a9582@intel.com>

On Wed, Apr 29, 2020 at 11:42:03AM -0700, Reinette Chatre wrote:
> This would essentially be resubmitting [1] though. Do you expect that
> this change would receive a different reception at this time?

Right, Thomas and I talked it over a bit last night. So the proper
thing to do is to read all that information *once* and put it in
boot_cpu_data. Because that information is replicated the same over
CPUID on each core. If there's per-CPU stuff, then it should remain
per-CPU but looking at how the RDT code uses boot_cpu_data, I'd say this
is global info.

So, it should be parsed once on the BSP during boot and put into
boot_cpu_data. And then silly stuff like x86_init_cache_qos() should go
away too.

If this info is needed on Intel only, then it should be parsed in
cpu/intel.c, in a ->c_bsp_init helper and if it is needed on AMD too,
then a function which does this should be called by the respective
c_bsp_init helper.

Then all its users can continue reading it out of boot_cpu_data and
future RDT hw info can be added there.

Makes sense?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2020-04-30  9:59 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-01 17:51 [PATCH 0/2] x86/resctrl: Support wider MBM counters Reinette Chatre
2020-04-01 17:51 ` [PATCH 1/2] x86/resctrl: Maintain MBM counter width per resource Reinette Chatre
2020-04-01 17:51 ` [PATCH 2/2] x86/resctrl: Support CPUID enumeration of MBM counter width Reinette Chatre
2020-04-03  0:05   ` Fenghua Yu
2020-04-03 15:31     ` Reinette Chatre
2020-04-29 18:11   ` Borislav Petkov
2020-04-29 18:42     ` Reinette Chatre
2020-04-30  9:59       ` Borislav Petkov [this message]
2020-05-03 18:51         ` Reinette Chatre
2020-05-04  7:56           ` Borislav Petkov
2020-05-05  4:19             ` Reinette Chatre
2020-05-05 22:15               ` Reinette Chatre
2020-04-23 16:40 ` [PATCH 0/2] x86/resctrl: Support wider MBM counters Reinette Chatre

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