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From: Arjan van de Ven <arjan@linux.intel.com>
To: David Woodhouse <dwmw2@infradead.org>,
	Usama Arif <usama.arif@bytedance.com>,
	tglx@linutronix.de
Cc: mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	hpa@zytor.com, x86@kernel.org, pbonzini@redhat.com,
	paulmck@kernel.org, linux-kernel@vger.kernel.org,
	kvm@vger.kernel.org, rcu@vger.kernel.org, mimoja@mimoja.de,
	hewenliang4@huawei.com, thomas.lendacky@amd.com,
	seanjc@google.com, pmenzel@molgen.mpg.de,
	fam.zheng@bytedance.com, punit.agrawal@bytedance.com,
	simon.evans@bytedance.com, liangma@liangbit.com
Subject: Re: [External] Re: [PATCH v6 06/11] x86/smpboot: Support parallel startup of secondary CPUs
Date: Fri, 3 Feb 2023 06:41:50 -0800	[thread overview]
Message-ID: <e4350e62-b1b4-ad1f-d757-959dace44402@linux.intel.com> (raw)
In-Reply-To: <fb72e7ae7b78e75a53acdb62960bdee8de5cb207.camel@infradead.org>

On 2/3/2023 12:14 AM, David Woodhouse wrote:
> On Thu, 2023-02-02 at 22:50 +0000, Usama Arif wrote:
>>
>> Ah, sorry about that, should have caught it while reviewing before
>> posting. To think of it, it might be better to squash this and next AMD
>> disabling patch, if anyone testing on AMD ever happens to check out at
>> this specific patch, their machine might not boot :).
>>
> 
> Nah, we don't actually *enable* parallel boot until the next patch
> anyway. At this point we're only laying the groundwork. I think it's
> best separate.
> 
>> Will repost only after getting the OK for the rest of the patches
>> along with addressing any other comments that come up.
> 
> Ack. And hopefully the missing SoB from both Thomas and Arjan for their
> parts. Part of the reasoning for the lack of SoB from Arjan might have
> been that we haven't finished doing the thinking about how this works
> in all cases, with non-constant TSC and other stuff. Let's make sure we
> give that a long hard stare.

most of it is that I need to sit down for some real time and have a think through it ;)

for all the common cases / modern HW it will be ok... but all the rest???

maybe we need a strict(er) safety valve on where this is used and then over time
widen the usage?

(after all, a regression means revert, and maybe it's better to only revert "add CPU type X" than
revert the whole series)


  reply	other threads:[~2023-02-03 14:42 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-02 21:56 [PATCH v6 00/11] Parallel CPU bringup for x86_64 Usama Arif
2023-02-02 21:56 ` [PATCH v6 01/11] x86/apic/x2apic: Fix parallel handling of cluster_mask Usama Arif
2023-02-06 23:20   ` Thomas Gleixner
2023-02-07 10:57     ` David Woodhouse
2023-02-07 11:27       ` David Woodhouse
2023-02-07 14:24         ` Thomas Gleixner
2023-02-07 19:53           ` David Woodhouse
2023-02-07 20:58             ` Thomas Gleixner
2023-02-07 14:22       ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 02/11] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> Usama Arif
2023-02-06 23:33   ` Thomas Gleixner
2023-02-07  1:24     ` Paul E. McKenney
2023-02-02 21:56 ` [PATCH v6 03/11] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU Usama Arif
2023-02-06 23:43   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 04/11] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Usama Arif
2023-02-06 23:48   ` Thomas Gleixner
     [not found]     ` <57195f701f6d1d70ec440c9a28cbee4cfb81dc41.camel@amazon.co.uk>
2023-02-07 14:39       ` Thomas Gleixner
2023-02-07 16:50         ` Sean Christopherson
2023-02-07 19:48         ` [EXTERNAL][PATCH " David Woodhouse
2023-02-02 21:56 ` [PATCH v6 05/11] x86/smpboot: Split up native_cpu_up into separate phases and document them Usama Arif
2023-02-06 23:59   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 06/11] x86/smpboot: Support parallel startup of secondary CPUs Usama Arif
2023-02-02 22:30   ` David Woodhouse
2023-02-02 22:50     ` [External] " Usama Arif
2023-02-03  8:14       ` David Woodhouse
2023-02-03 14:41         ` Arjan van de Ven [this message]
2023-02-03 18:17   ` Sean Christopherson
2023-02-07  0:07   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 07/11] x86/smpboot: Disable parallel boot for AMD CPUs Usama Arif
2023-02-03 19:48   ` Kim Phillips
     [not found]     ` <d5ec64236ba75f0d3f3718fb69b2cb9169d8af0a.camel@amazon.co.uk>
2023-02-03 21:45       ` Kim Phillips
2023-02-03 22:25         ` [EXTERNAL][PATCH " David Woodhouse
2023-02-04  9:07     ` [PATCH " David Woodhouse
2023-02-04 10:09     ` David Woodhouse
2023-02-04 15:40     ` David Woodhouse
2023-02-04 18:18       ` Arjan van de Ven
2023-02-04 22:31         ` David Woodhouse
2023-02-05 22:13           ` [External] " Usama Arif
2023-02-06  8:05             ` David Woodhouse
2023-02-06 12:11               ` Usama Arif
2023-02-06 18:07                 ` Sean Christopherson
2023-02-06 17:58       ` Kim Phillips
2023-02-07 16:27         ` Kim Phillips
2023-02-07  0:23       ` Thomas Gleixner
2023-02-07 10:04         ` David Woodhouse
2023-02-07 14:44           ` Thomas Gleixner
2023-02-07  0:09   ` Thomas Gleixner
     [not found]     ` <cbd9e88e738dc0c479e87121ca82431731905c73.camel@amazon.co.uk>
2023-02-07 14:46       ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 08/11] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel Usama Arif
2023-02-07  0:28   ` Thomas Gleixner
2023-02-02 21:56 ` [PATCH v6 09/11] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup Usama Arif
2023-02-02 21:56 ` [PATCH v6 10/11] x86/smpboot: Serialize topology updates for secondary bringup Usama Arif
2023-02-02 21:56 ` [PATCH v6 11/11] x86/smpboot: reuse timer calibration Usama Arif
2023-02-07  0:31   ` Thomas Gleixner
2023-02-07 23:16   ` Arjan van de Ven
2023-02-07 23:55     ` Thomas Gleixner
2023-02-05 19:17 ` [PATCH v6 00/11] Parallel CPU bringup for x86_64 Russ Anderson
2023-02-06  8:28   ` David Woodhouse
2023-02-06 12:18     ` [External] " Usama Arif

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