From: David Woodhouse <dwmw2@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>,
Usama Arif <usama.arif@bytedance.com>,
Oleksandr Natalenko <oleksandr@natalenko.name>
Cc: Kim Phillips <kim.phillips@amd.com>,
arjan@linux.intel.com, 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, "Limonciello,
Mario" <Mario.Limonciello@amd.com>,
Piotr Gorski <piotrgorski@cachyos.org>
Subject: Re: [External] Re: [PATCH v9 0/8] Parallel CPU bringup for x86_64
Date: Wed, 22 Feb 2023 09:51:04 +0000 [thread overview]
Message-ID: <fc845767a39a8b0fa692a2380eeb3a75c8b09774.camel@infradead.org> (raw)
In-Reply-To: <87cz62m3ri.ffs@tglx>
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On Wed, 2023-02-22 at 10:46 +0100, Thomas Gleixner wrote:
> On Wed, Feb 22 2023 at 08:19, David Woodhouse wrote:
> > But the BSP/CPU0 is different. It hasn't actually been taken offline,
> > and its idle thread context is still in cpu_startup_entry(CPUHP_ONLINE)
> > which got called from rest_init().
> >
> > In testing I probably got away with it because we're only using the
> > *top* of the stack, don't use anything of the red zone, and thus don't
> > actually bother the true idle thread which is never going to return.
>
> :)
>
> > But I don't think it's correct; we really ought to have that temp_stack
> > unless we're going to refactor the wakeup_64 code to *become* the idle
> > thread just as startup_secondary() does, and *schedule* to the context
> > that was saved in the suspend code.
>
> And thereby messing up the scheduler state...
Indeed. Which is probably fixable but also probably more of a wart in
the scheduler code, than it's worth for the negligible cleanup in the
suspend code.
Hence "not today". Which is code for "not ever". But don't tell my
children that.
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next prev parent reply other threads:[~2023-02-22 9:53 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-15 14:54 [PATCH v9 0/8] Parallel CPU bringup for x86_64 Usama Arif
2023-02-15 14:54 ` [PATCH v9 1/8] x86/apic/x2apic: Allow CPU cluster_mask to be populated in parallel Usama Arif
2023-02-16 20:58 ` Kim Phillips
2023-02-15 14:54 ` [PATCH v9 2/8] cpu/hotplug: Move idle_thread_get() to <linux/smpboot.h> Usama Arif
2023-02-15 14:54 ` [PATCH v9 3/8] cpu/hotplug: Add dynamic parallel bringup states before CPUHP_BRINGUP_CPU Usama Arif
2023-02-15 14:54 ` [PATCH v9 4/8] x86/smpboot: Reference count on smpboot_setup_warm_reset_vector() Usama Arif
2023-02-15 14:54 ` [PATCH v9 5/8] x86/smpboot: Split up native_cpu_up into separate phases and document them Usama Arif
2023-02-15 14:54 ` [PATCH v9 6/8] x86/smpboot: Support parallel startup of secondary CPUs Usama Arif
2023-02-15 14:54 ` [PATCH v9 7/8] x86/smpboot: Send INIT/SIPI/SIPI to secondary CPUs in parallel Usama Arif
2023-02-15 14:54 ` [PATCH v9 8/8] x86/smpboot: Serialize topology updates for secondary bringup Usama Arif
2023-02-16 6:34 ` [PATCH v9 0/8] Parallel CPU bringup for x86_64 Paul E. McKenney
2023-02-20 16:08 ` Oleksandr Natalenko
2023-02-20 16:20 ` David Woodhouse
2023-02-20 16:40 ` Oleksandr Natalenko
2023-02-20 20:31 ` David Woodhouse
2023-02-20 21:23 ` Oleksandr Natalenko
2023-02-20 21:34 ` Piotr Gorski
2023-02-20 21:39 ` David Woodhouse
2023-02-20 23:23 ` Kim Phillips
2023-02-20 23:30 ` David Woodhouse
2023-02-21 4:20 ` Kim Phillips
2023-02-21 7:16 ` David Woodhouse
2023-02-21 7:27 ` Oleksandr Natalenko
2023-02-21 7:53 ` David Woodhouse
2023-02-21 8:05 ` Oleksandr Natalenko
2023-02-21 8:17 ` David Woodhouse
2023-02-21 8:25 ` Oleksandr Natalenko
2023-02-21 8:35 ` David Woodhouse
2023-02-21 8:44 ` Oleksandr Natalenko
2023-02-21 9:06 ` David Woodhouse
2023-02-21 9:49 ` Oleksandr Natalenko
2023-02-21 10:27 ` David Woodhouse
2023-02-21 10:47 ` [External] " Usama Arif
2023-02-21 11:42 ` Oleksandr Natalenko
2023-02-21 11:54 ` Usama Arif
2023-02-21 13:22 ` David Woodhouse
2023-02-21 11:46 ` Oleksandr Natalenko
2023-02-21 11:49 ` David Woodhouse
2023-02-21 12:14 ` Oleksandr Natalenko
2023-02-21 19:10 ` David Woodhouse
2023-02-21 20:04 ` [External] " Usama Arif
2023-02-21 21:04 ` Oleksandr Natalenko
2023-02-21 21:41 ` Thomas Gleixner
2023-02-21 21:44 ` David Woodhouse
2023-02-21 23:18 ` David Woodhouse
2023-02-22 0:00 ` [External] " Usama Arif
2023-02-22 8:19 ` David Woodhouse
2023-02-22 9:46 ` Thomas Gleixner
2023-02-22 9:51 ` David Woodhouse [this message]
2023-02-22 9:31 ` Thomas Gleixner
2023-02-20 22:22 ` Piotr Gorski
2023-02-20 22:23 ` [External] " Usama Arif
2023-02-20 22:41 ` Oleksandr Natalenko
2023-02-22 10:11 ` David Woodhouse
2023-02-22 11:11 ` [External] " Usama Arif
2023-02-22 12:08 ` Brian Gerst
2023-02-22 12:53 ` David Woodhouse
2023-02-22 16:42 ` Thomas Gleixner
2023-02-23 11:07 ` David Woodhouse
2023-02-23 14:37 ` Thomas Gleixner
2023-02-23 15:12 ` David Woodhouse
2023-02-23 19:24 ` [External] " Usama Arif
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